fix(highlight): support combined diff format for unmerged files

Problem: fugitive shows combined diffs (@@@ headers, 2-char prefixes)
for unmerged (UU) files. The parser and highlight pipeline assumed
unified diff format (@@, 1-char prefix), causing broken prefix
concealment, missing background colors on ` +`/`+ ` lines, and no
treesitter highlights due to garbage prefix chars in code arrays.

Solution: detect prefix width from the number of leading @ signs in
hunk headers. Propagate prefix_width through the parser (new field on
diffs.Hunk) and highlight pipeline (prefix stripping, col_offset,
concealment, line classification). Add U to filename pattern for
unmerged file detection. Skip intra-line diffing for combined diffs
since the 2-char prefix semantics don't produce meaningful change
groups.

README.md

@@ -9,18 +9,14 @@ syntax highlighting.
 
 ## Features
 
-- Treesitter syntax highlighting in `:Git` diffs and commit views
+- Treesitter syntax highlighting in fugitive diffs and commit views
-- Diff header highlighting (`diff --git`, `index`, `---`, `+++`)
+- Character-level intra-line diff highlighting (with optional
-- `:Gdiffsplit` / `:Gvdiffsplit` syntax through diff backgrounds
+  [vscode-diff](https://github.com/esmuellert/codediff.nvim) FFI backend for
-- `:Gdiff` unified diff against any git revision with syntax highlighting
+  word-level accuracy)
-- Fugitive status buffer keymaps (`du`/`dU`) for unified diffs
+- `:Gdiff` unified diff against any revision
-- Background-only diff colors for any `&diff` buffer (`:diffthis`, `vimdiff`)
+- Background-only diff colors for `&diff` buffers
-- Vim syntax fallback for languages without a treesitter parser
+- Inline merge conflict detection, highlighting, and resolution
-- Hunk header context highlighting (`@@ ... @@ function foo()`)
+- Vim syntax fallback, configurable blend/debounce/priorities
-- Character-level (intra-line) diff highlighting for changed characters
-- Inline merge conflict detection, highlighting, and resolution keymaps
-- Configurable debouncing, max lines, diff prefix concealment, blend alpha, and
-  highlight overrides
 
 ## Requirements
 
@@ -44,10 +40,9 @@ luarocks install diffs.nvim
 ## Known Limitations
 
 - **Incomplete syntax context**: Treesitter parses each diff hunk in isolation.
-  To improve accuracy, `diffs.nvim` reads lines from disk before and after each
+  Context lines within the hunk (` ` prefix) provide syntactic context for the
-  hunk for parsing context (`highlights.context`, enabled by default with 25
+  parser. In rare cases, hunks that start or end mid-expression may produce
-  lines). This resolves most boundary issues. Set
+  imperfect highlights due to treesitter error recovery.
-  `highlights.context.enabled = false` to disable.
 
 - **Syntax flashing**: `diffs.nvim` hooks into the `FileType fugitive` event
   triggered by `vim-fugitive`, at which point the buffer is preliminarily
@@ -70,7 +65,9 @@ luarocks install diffs.nvim
 # Acknowledgements
 
 - [`vim-fugitive`](https://github.com/tpope/vim-fugitive)
-- [`codediff.nvim`](https://github.com/esmuellert/codediff.nvim)
+- [@esmuellert](https://github.com/esmuellert) /
+  [`codediff.nvim`](https://github.com/esmuellert/codediff.nvim) - vscode-diff
+  algorithm FFI backend for word-level intra-line accuracy
 - [`diffview.nvim`](https://github.com/sindrets/diffview.nvim)
 - [`difftastic`](https://github.com/Wilfred/difftastic)
 - [`mini.diff`](https://github.com/echasnovski/mini.diff)

doc/diffs.nvim.txt

@@ -75,6 +75,12 @@ Configuration is done via `vim.g.diffs`. Set this before the plugin loads:
           algorithm = 'default',
           max_lines = 500,
         },
+        priorities = {
+          clear = 198,
+          syntax = 199,
+          line_bg = 200,
+          char_bg = 201,
+        },
         overrides = {},
       },
       fugitive = {
@@ -85,6 +91,7 @@ Configuration is done via `vim.g.diffs`. Set this before the plugin loads:
         enabled = true,
         disable_diagnostics = true,
         show_virtual_text = true,
+        show_actions = false,
         keymaps = {
           ours = 'doo',
           theirs = 'dot',
@@ -160,6 +167,10 @@ Configuration is done via `vim.g.diffs`. Set this before the plugin loads:
                              Character-level (intra-line) diff highlighting.
                              See |diffs.IntraConfig| for fields.
 
+        {priorities}         (table, default: see below)
+                             Extmark priority values.
+                             See |diffs.PrioritiesConfig| for fields.
+
         {overrides}          (table, default: {})
                              Map of highlight group names to highlight
                              definitions (see |nvim_set_hl()|). Applied
@@ -181,6 +192,28 @@ Configuration is done via `vim.g.diffs`. Set this before the plugin loads:
                              direction. Lines are read with early exit —
                              cost scales with this value, not file size.
 
+                                                   *diffs.PrioritiesConfig*
+    Priorities config fields: ~
+        {clear}              (integer, default: 198)
+                             Priority for `DiffsClear` extmarks that reset
+                             underlying diff foreground colors. Must be
+                             below {syntax}.
+
+        {syntax}             (integer, default: 199)
+                             Priority for treesitter and vim syntax extmarks.
+                             Must be below {line_bg} so that colorscheme
+                             backgrounds on syntax groups do not obscure
+                             line-level diff backgrounds.
+
+        {line_bg}            (integer, default: 200)
+                             Priority for `DiffsAdd`/`DiffsDelete` line
+                             background extmarks. Must be below {char_bg}.
+
+        {char_bg}            (integer, default: 201)
+                             Priority for `DiffsAddText`/`DiffsDeleteText`
+                             character-level background extmarks. Highest
+                             priority so changed characters stand out.
+
                                                     *diffs.TreesitterConfig*
     Treesitter config fields: ~
         {enabled}            (boolean, default: true)
@@ -280,6 +313,67 @@ Example configuration: >lua
     vim.keymap.set('n', '<leader>gD', '<Plug>(diffs-gvdiff)')
 <
 
+                                              *<Plug>(diffs-conflict-ours)*
+<Plug>(diffs-conflict-ours)
+                        Accept current (ours) change. Replaces the
+                        conflict block with ours content.
+
+                                            *<Plug>(diffs-conflict-theirs)*
+<Plug>(diffs-conflict-theirs)
+                        Accept incoming (theirs) change. Replaces the
+                        conflict block with theirs content.
+
+                                              *<Plug>(diffs-conflict-both)*
+<Plug>(diffs-conflict-both)
+                        Accept both changes (ours then theirs).
+
+                                              *<Plug>(diffs-conflict-none)*
+<Plug>(diffs-conflict-none)
+                        Reject both changes (delete entire block).
+
+                                              *<Plug>(diffs-conflict-next)*
+<Plug>(diffs-conflict-next)
+                        Jump to next conflict marker. Wraps around.
+
+                                              *<Plug>(diffs-conflict-prev)*
+<Plug>(diffs-conflict-prev)
+                        Jump to previous conflict marker. Wraps around.
+
+Example configuration: >lua
+    vim.keymap.set('n', 'co', '<Plug>(diffs-conflict-ours)')
+    vim.keymap.set('n', 'ct', '<Plug>(diffs-conflict-theirs)')
+    vim.keymap.set('n', 'cb', '<Plug>(diffs-conflict-both)')
+    vim.keymap.set('n', 'cn', '<Plug>(diffs-conflict-none)')
+    vim.keymap.set('n', ']x', '<Plug>(diffs-conflict-next)')
+    vim.keymap.set('n', '[x', '<Plug>(diffs-conflict-prev)')
+<
+
+                                                 *<Plug>(diffs-merge-ours)*
+<Plug>(diffs-merge-ours)
+                        Accept ours in a merge diff view. Resolves the
+                        conflict in the working file with ours content.
+
+                                               *<Plug>(diffs-merge-theirs)*
+<Plug>(diffs-merge-theirs)
+                        Accept theirs in a merge diff view.
+
+                                                 *<Plug>(diffs-merge-both)*
+<Plug>(diffs-merge-both)
+                        Accept both (ours then theirs) in a merge diff view.
+
+                                                 *<Plug>(diffs-merge-none)*
+<Plug>(diffs-merge-none)
+                        Reject both in a merge diff view.
+
+                                                 *<Plug>(diffs-merge-next)*
+<Plug>(diffs-merge-next)
+                        Jump to next unresolved conflict hunk in merge diff.
+
+                                                 *<Plug>(diffs-merge-prev)*
+<Plug>(diffs-merge-prev)
+                        Jump to previous unresolved conflict hunk in merge
+                        diff.
+
 Diff buffer mappings: ~
                                                               *diffs-q*
     q               Close the diff window. Available in all `diffs://`
@@ -310,6 +404,7 @@ Behavior by file status: ~
     A           Staged      (empty)         index           file as all-added
     D           Staged      HEAD            (empty)         file as all-removed
     R           Staged      HEAD:oldname    index:newname   content diff
+    U           Unstaged    :2: (ours)      :3: (theirs)    merge diff
     ?           Untracked   (empty)         working tree    file as all-added
 
 On section headers, the keymap runs `git diff` (or `git diff --cached` for
@@ -354,6 +449,8 @@ Configuration: ~
         enabled = true,
         disable_diagnostics = true,
         show_virtual_text = true,
+        show_actions = false,
+        priority = 200,
         keymaps = {
           ours = 'doo',
           theirs = 'dot',
@@ -380,9 +477,37 @@ Configuration: ~
                              diagnostics alone.
 
         {show_virtual_text}  (boolean, default: true)
-                             Show virtual text labels (" current" and
+                             Show `(current)` and `(incoming)` labels at
-                             " incoming") at the end of `<<<<<<<` and
+                             the end of `<<<<<<<` and `>>>>>>>` marker
-                             `>>>>>>>` marker lines.
+                             lines. Also controls hunk hints in merge
+                             diff views.
+
+        {format_virtual_text} (function|nil, default: nil)
+                             Custom formatter for virtual text labels.
+                             Receives `(side, keymap)` where `side` is
+                             `"ours"` or `"theirs"` and `keymap` is the
+                             configured keymap string or `false`. Return
+                             a string (label text without parens) or
+                             `nil` to hide the label. Example: >lua
+                                 format_virtual_text = function(side, keymap)
+                                   if keymap then
+                                     return side .. ' [' .. keymap .. ']'
+                                   end
+                                   return side
+                                 end
+<
+
+        {show_actions}       (boolean, default: false)
+                             Show a codelens-style action line above each
+                             `<<<<<<<` marker listing available resolution
+                             keymaps. Renders as virtual lines using the
+                             `DiffsConflictActions` highlight group.
+                             Only keymaps that are not `false` appear.
+
+        {priority}           (integer, default: 200)
+                             Extmark priority for conflict region
+                             backgrounds and markers. Adjust if other
+                             plugins use the same priority range.
 
         {keymaps}            (table, default: see above)
                              Buffer-local keymaps for conflict resolution
@@ -423,6 +548,31 @@ User events: ~
                                 })
 <
 
+==============================================================================
+MERGE DIFF RESOLUTION                                       *diffs-merge*
+
+When pressing `du`/`dU` on an unmerged (`U`) file in the fugitive status
+buffer, diffs.nvim opens a unified diff of ours (`git show :2:path`) vs
+theirs (`git show :3:path`) with full treesitter and intra-line highlighting.
+
+The same conflict resolution keymaps (`doo`/`dot`/`dob`/`don`/`]x`/`[x`)
+are available on the diff buffer. They resolve conflicts in the working
+file by matching diff hunks to conflict markers:
+
+- `doo` replaces the conflict region with ours content
+- `dot` replaces the conflict region with theirs content
+- `dob` replaces with both (ours then theirs)
+- `don` removes the conflict region entirely
+- `]x`/`[x` navigate between unresolved conflict hunks
+
+Resolved hunks are marked with `(resolved)` virtual text. Hunks that
+correspond to auto-merged content (no conflict markers) show an
+informational notification and are left unchanged.
+
+The working file buffer is modified in place; save it when ready.
+Phase 1 inline conflict highlights (see |diffs-conflict|) are refreshed
+automatically after each resolution.
+
 ==============================================================================
 API                                                                *diffs-api*
 
@@ -454,12 +604,13 @@ Summary / commit detail views: ~
    - Code is parsed with |vim.treesitter.get_string_parser()|
    - If no treesitter parser and `vim.enabled`: vim syntax fallback via
      scratch buffer and |synID()|
-   - `Normal` extmarks at priority 198 clear underlying diff foreground
+   - `DiffsClear` extmarks at priority 198 clear underlying diff foreground
-   - Background extmarks (`DiffsAdd`/`DiffsDelete`) at priority 199
+   - Syntax highlights are applied as extmarks at priority 199
-   - Syntax highlights are applied as extmarks at priority 200
+   - Background extmarks (`DiffsAdd`/`DiffsDelete`) at priority 200
    - Character-level diff extmarks (`DiffsAddText`/`DiffsDeleteText`) at
      priority 201 overlay changed characters with an intense background
    - Conceal extmarks hide diff prefixes when `hide_prefix` is enabled
+   - All priorities are configurable via |diffs.PrioritiesConfig|
 4. Re-highlighting occurs on `TextChanged` (debounced) and `Syntax` events
 
 Diff mode views: ~
@@ -474,15 +625,10 @@ KNOWN LIMITATIONS                                       *diffs-limitations*
 
 Incomplete Syntax Context ~
                                                       *diffs-syntax-context*
-Treesitter parses each diff hunk in isolation. To provide surrounding code
+Treesitter parses each diff hunk in isolation. Context lines within the hunk
-context, diffs.nvim reads lines from disk before and after each hunk
+(lines with a ` ` prefix) provide syntactic context for the parser. In rare
-(see |diffs.ContextConfig|, enabled by default). This resolves most boundary
+cases, hunks that start or end mid-expression may produce imperfect highlights
-issues where incomplete constructs (e.g., a function definition at the edge
+due to treesitter error recovery.
-of a hunk with no body) would confuse the parser.
-
-Set `highlights.context.enabled = false` to disable context padding. In rare
-cases, context padding may not help if the relevant surrounding code is very
-far from the hunk boundaries.
 
 Syntax Highlighting Flash ~
                                                              *diffs-flash*
@@ -600,6 +746,10 @@ Conflict highlights: ~
                                                       *DiffsConflictBaseNr*
     DiffsConflictBaseNr Line number for base content lines (diff3).
 
+                                                    *DiffsConflictActions*
+    DiffsConflictActions Dimmed foreground (no bold) for the codelens-style
+                        action line shown when `show_actions` is true.
+
 Diff mode window highlights: ~
 These are used for |winhighlight| remapping in `&diff` windows.
 

lua/diffs/commands.lua

@@ -36,6 +36,24 @@ function M.find_hunk_line(diff_lines, hunk_position)
   return nil
 end
 
+---@param lines string[]
+---@return string[]
+function M.filter_combined_diffs(lines)
+  local result = {}
+  local skip = false
+  for _, line in ipairs(lines) do
+    if line:match('^diff %-%-cc ') then
+      skip = true
+    elseif line:match('^diff %-%-git ') then
+      skip = false
+    end
+    if not skip then
+      table.insert(result, line)
+    end
+  end
+  return result
+end
+
 ---@param old_lines string[]
 ---@param new_lines string[]
 ---@param old_name string
@@ -69,6 +87,33 @@ local function generate_unified_diff(old_lines, new_lines, old_name, new_name)
   return result
 end
 
+---@param raw_lines string[]
+---@param repo_root string
+---@return string[]
+local function replace_combined_diffs(raw_lines, repo_root)
+  local unmerged_files = {}
+  for _, line in ipairs(raw_lines) do
+    local cc_file = line:match('^diff %-%-cc (.+)$')
+    if cc_file then
+      table.insert(unmerged_files, cc_file)
+    end
+  end
+
+  local result = M.filter_combined_diffs(raw_lines)
+
+  for _, filename in ipairs(unmerged_files) do
+    local filepath = repo_root .. '/' .. filename
+    local old_lines = git.get_file_content(':2', filepath) or {}
+    local new_lines = git.get_file_content(':3', filepath) or {}
+    local diff_lines = generate_unified_diff(old_lines, new_lines, filename, filename)
+    for _, dl in ipairs(diff_lines) do
+      table.insert(result, dl)
+    end
+  end
+
+  return result
+end
+
 ---@param revision? string
 ---@param vertical? boolean
 function M.gdiff(revision, vertical)
@@ -138,6 +183,7 @@ end
 ---@field vertical? boolean
 ---@field staged? boolean
 ---@field untracked? boolean
+---@field unmerged? boolean
 ---@field old_filepath? string
 ---@field hunk_position? { hunk_header: string, offset: integer }
 
@@ -157,7 +203,17 @@ function M.gdiff_file(filepath, opts)
   local old_lines, new_lines, err
   local diff_label
 
-  if opts.untracked then
+  if opts.unmerged then
+    old_lines = git.get_file_content(':2', filepath)
+    if not old_lines then
+      old_lines = {}
+    end
+    new_lines = git.get_file_content(':3', filepath)
+    if not new_lines then
+      new_lines = {}
+    end
+    diff_label = 'unmerged'
+  elseif opts.untracked then
     old_lines = {}
     new_lines, err = git.get_working_content(filepath)
     if not new_lines then
@@ -236,6 +292,14 @@ function M.gdiff_file(filepath, opts)
   end
 
   M.setup_diff_buf(diff_buf)
+
+  if diff_label == 'unmerged' then
+    vim.api.nvim_buf_set_var(diff_buf, 'diffs_unmerged', true)
+    vim.api.nvim_buf_set_var(diff_buf, 'diffs_working_path', filepath)
+    local conflict_config = require('diffs').get_conflict_config()
+    require('diffs.merge').setup_keymaps(diff_buf, conflict_config)
+  end
+
   dbg('opened diff buffer %d for %s (%s)', diff_buf, rel_path, diff_label)
 
   vim.schedule(function()
@@ -263,6 +327,8 @@ function M.gdiff_section(repo_root, opts)
     return
   end
 
+  result = replace_combined_diffs(result, repo_root)
+
   if #result == 0 then
     vim.notify('[diffs.nvim]: no changes in section', vim.log.levels.INFO)
     return
@@ -325,6 +391,8 @@ function M.read_buffer(bufnr)
     if vim.v.shell_error ~= 0 then
       diff_lines = {}
     end
+
+    diff_lines = replace_combined_diffs(diff_lines, repo_root)
   else
     local abs_path = repo_root .. '/' .. path
 
@@ -334,7 +402,10 @@ function M.read_buffer(bufnr)
 
     local old_lines, new_lines
 
-    if label == 'untracked' then
+    if label == 'unmerged' then
+      old_lines = git.get_file_content(':2', abs_path) or {}
+      new_lines = git.get_file_content(':3', abs_path) or {}
+    elseif label == 'untracked' then
       old_lines = {}
       new_lines = git.get_working_content(abs_path) or {}
     elseif label == 'staged' then

lua/diffs/conflict.lua

@@ -20,8 +20,6 @@ local attached_buffers = {}
 ---@type table<integer, boolean>
 local diagnostics_suppressed = {}
 
-local PRIORITY_LINE_BG = 200
-
 ---@param lines string[]
 ---@return diffs.ConflictRegion[]
 function M.parse(lines)
@@ -92,6 +90,17 @@ local function parse_buffer(bufnr)
   return M.parse(lines)
 end
 
+---@param side string
+---@param config diffs.ConflictConfig
+---@return string?
+local function get_virtual_text_label(side, config)
+  if config.format_virtual_text then
+    local keymap = side == 'ours' and config.keymaps.ours or config.keymaps.theirs
+    return config.format_virtual_text(side, keymap)
+  end
+  return side == 'ours' and 'current' or 'incoming'
+end
+
 ---@param bufnr integer
 ---@param regions diffs.ConflictRegion[]
 ---@param config diffs.ConflictConfig
@@ -103,14 +112,41 @@ local function apply_highlights(bufnr, regions, config)
       end_row = region.marker_ours + 1,
       hl_group = 'DiffsConflictMarker',
       hl_eol = true,
-      priority = PRIORITY_LINE_BG,
+      priority = config.priority,
     })
 
     if config.show_virtual_text then
-      pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, region.marker_ours, 0, {
+      local ours_label = get_virtual_text_label('ours', config)
-        virt_text = { { ' (current)', 'DiffsConflictMarker' } },
+      if ours_label then
-        virt_text_pos = 'eol',
+        pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, region.marker_ours, 0, {
-      })
+          virt_text = { { ' (' .. ours_label .. ')', 'DiffsConflictMarker' } },
+          virt_text_pos = 'eol',
+        })
+      end
+    end
+
+    if config.show_actions then
+      local parts = {}
+      local actions = {
+        { 'Current', config.keymaps.ours },
+        { 'Incoming', config.keymaps.theirs },
+        { 'Both', config.keymaps.both },
+        { 'None', config.keymaps.none },
+      }
+      for _, action in ipairs(actions) do
+        if action[2] then
+          if #parts > 0 then
+            table.insert(parts, { ' \226\148\130 ', 'DiffsConflictActions' })
+          end
+          table.insert(parts, { ('%s (%s)'):format(action[1], action[2]), 'DiffsConflictActions' })
+        end
+      end
+      if #parts > 0 then
+        pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, region.marker_ours, 0, {
+          virt_lines = { parts },
+          virt_lines_above = true,
+        })
+      end
     end
 
     for line = region.ours_start, region.ours_end - 1 do
@@ -118,11 +154,11 @@ local function apply_highlights(bufnr, regions, config)
         end_row = line + 1,
         hl_group = 'DiffsConflictOurs',
         hl_eol = true,
-        priority = PRIORITY_LINE_BG,
+        priority = config.priority,
       })
       pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, line, 0, {
         number_hl_group = 'DiffsConflictOursNr',
-        priority = PRIORITY_LINE_BG,
+        priority = config.priority,
       })
     end
 
@@ -131,7 +167,7 @@ local function apply_highlights(bufnr, regions, config)
         end_row = region.marker_base + 1,
         hl_group = 'DiffsConflictMarker',
         hl_eol = true,
-        priority = PRIORITY_LINE_BG,
+        priority = config.priority,
       })
 
       for line = region.base_start, region.base_end - 1 do
@@ -139,11 +175,11 @@ local function apply_highlights(bufnr, regions, config)
           end_row = line + 1,
           hl_group = 'DiffsConflictBase',
           hl_eol = true,
-          priority = PRIORITY_LINE_BG,
+          priority = config.priority,
         })
         pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, line, 0, {
           number_hl_group = 'DiffsConflictBaseNr',
-          priority = PRIORITY_LINE_BG,
+          priority = config.priority,
         })
       end
     end
@@ -152,7 +188,7 @@ local function apply_highlights(bufnr, regions, config)
       end_row = region.marker_sep + 1,
       hl_group = 'DiffsConflictMarker',
       hl_eol = true,
-      priority = PRIORITY_LINE_BG,
+      priority = config.priority,
     })
 
     for line = region.theirs_start, region.theirs_end - 1 do
@@ -160,11 +196,11 @@ local function apply_highlights(bufnr, regions, config)
         end_row = line + 1,
         hl_group = 'DiffsConflictTheirs',
         hl_eol = true,
-        priority = PRIORITY_LINE_BG,
+        priority = config.priority,
       })
       pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, line, 0, {
         number_hl_group = 'DiffsConflictTheirsNr',
-        priority = PRIORITY_LINE_BG,
+        priority = config.priority,
       })
     end
 
@@ -172,14 +208,17 @@ local function apply_highlights(bufnr, regions, config)
       end_row = region.marker_theirs + 1,
       hl_group = 'DiffsConflictMarker',
       hl_eol = true,
-      priority = PRIORITY_LINE_BG,
+      priority = config.priority,
     })
 
     if config.show_virtual_text then
-      pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, region.marker_theirs, 0, {
+      local theirs_label = get_virtual_text_label('theirs', config)
-        virt_text = { { ' (incoming)', 'DiffsConflictMarker' } },
+      if theirs_label then
-        virt_text_pos = 'eol',
+        pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, region.marker_theirs, 0, {
-      })
+          virt_text = { { ' (' .. theirs_label .. ')', 'DiffsConflictMarker' } },
+          virt_text_pos = 'eol',
+        })
+      end
     end
   end
 end
@@ -199,7 +238,7 @@ end
 ---@param bufnr integer
 ---@param region diffs.ConflictRegion
 ---@param replacement string[]
-local function replace_region(bufnr, region, replacement)
+function M.replace_region(bufnr, region, replacement)
   vim.api.nvim_buf_set_lines(
     bufnr,
     region.marker_ours,
@@ -211,7 +250,7 @@ end
 
 ---@param bufnr integer
 ---@param config diffs.ConflictConfig
-local function refresh(bufnr, config)
+function M.refresh(bufnr, config)
   local regions = parse_buffer(bufnr)
   if #regions == 0 then
     vim.api.nvim_buf_clear_namespace(bufnr, ns, 0, -1)
@@ -244,8 +283,8 @@ function M.resolve_ours(bufnr, config)
     return
   end
   local lines = vim.api.nvim_buf_get_lines(bufnr, region.ours_start, region.ours_end, false)
-  replace_region(bufnr, region, lines)
+  M.replace_region(bufnr, region, lines)
-  refresh(bufnr, config)
+  M.refresh(bufnr, config)
 end
 
 ---@param bufnr integer
@@ -262,8 +301,8 @@ function M.resolve_theirs(bufnr, config)
     return
   end
   local lines = vim.api.nvim_buf_get_lines(bufnr, region.theirs_start, region.theirs_end, false)
-  replace_region(bufnr, region, lines)
+  M.replace_region(bufnr, region, lines)
-  refresh(bufnr, config)
+  M.refresh(bufnr, config)
 end
 
 ---@param bufnr integer
@@ -288,8 +327,8 @@ function M.resolve_both(bufnr, config)
   for _, l in ipairs(theirs) do
     table.insert(combined, l)
   end
-  replace_region(bufnr, region, combined)
+  M.replace_region(bufnr, region, combined)
-  refresh(bufnr, config)
+  M.refresh(bufnr, config)
 end
 
 ---@param bufnr integer
@@ -305,8 +344,8 @@ function M.resolve_none(bufnr, config)
   if not region then
     return
   end
-  replace_region(bufnr, region, {})
+  M.replace_region(bufnr, region, {})
-  refresh(bufnr, config)
+  M.refresh(bufnr, config)
 end
 
 ---@param bufnr integer
@@ -323,6 +362,7 @@ function M.goto_next(bufnr)
       return
     end
   end
+  vim.notify('[diffs.nvim]: wrapped to first conflict', vim.log.levels.INFO)
   vim.api.nvim_win_set_cursor(0, { regions[1].marker_ours + 1, 0 })
 end
 
@@ -340,6 +380,7 @@ function M.goto_prev(bufnr)
       return
     end
   end
+  vim.notify('[diffs.nvim]: wrapped to last conflict', vim.log.levels.INFO)
   vim.api.nvim_win_set_cursor(0, { regions[#regions].marker_ours + 1, 0 })
 end
 
@@ -348,35 +389,19 @@ end
 local function setup_keymaps(bufnr, config)
   local km = config.keymaps
 
-  if km.ours then
+  local maps = {
-    vim.keymap.set('n', km.ours, function()
+    { km.ours, '<Plug>(diffs-conflict-ours)' },
-      M.resolve_ours(bufnr, config)
+    { km.theirs, '<Plug>(diffs-conflict-theirs)' },
-    end, { buffer = bufnr })
+    { km.both, '<Plug>(diffs-conflict-both)' },
-  end
+    { km.none, '<Plug>(diffs-conflict-none)' },
-  if km.theirs then
+    { km.next, '<Plug>(diffs-conflict-next)' },
-    vim.keymap.set('n', km.theirs, function()
+    { km.prev, '<Plug>(diffs-conflict-prev)' },
-      M.resolve_theirs(bufnr, config)
+  }
-    end, { buffer = bufnr })
+
-  end
+  for _, map in ipairs(maps) do
-  if km.both then
+    if map[1] then
-    vim.keymap.set('n', km.both, function()
+      vim.keymap.set('n', map[1], map[2], { buffer = bufnr })
-      M.resolve_both(bufnr, config)
+    end
-    end, { buffer = bufnr })
-  end
-  if km.none then
-    vim.keymap.set('n', km.none, function()
-      M.resolve_none(bufnr, config)
-    end, { buffer = bufnr })
-  end
-  if km.next then
-    vim.keymap.set('n', km.next, function()
-      M.goto_next(bufnr)
-    end, { buffer = bufnr })
-  end
-  if km.prev then
-    vim.keymap.set('n', km.prev, function()
-      M.goto_prev(bufnr)
-    end, { buffer = bufnr })
   end
 end
 
@@ -433,7 +458,7 @@ function M.attach(bufnr, config)
       if not attached_buffers[bufnr] then
         return true
       end
-      refresh(bufnr, config)
+      M.refresh(bufnr, config)
     end,
   })
 

lua/diffs/fugitive.lua

@@ -26,20 +26,65 @@ function M.get_section_at_line(bufnr, lnum)
   return nil
 end
 
+---@param s string
+---@return string
+local function unquote(s)
+  if s:sub(1, 1) ~= '"' then
+    return s
+  end
+  local inner = s:sub(2, -2)
+  local result = {}
+  local i = 1
+  while i <= #inner do
+    if inner:sub(i, i) == '\\' and i < #inner then
+      local next_char = inner:sub(i + 1, i + 1)
+      if next_char == 'n' then
+        table.insert(result, '\n')
+        i = i + 2
+      elseif next_char == 't' then
+        table.insert(result, '\t')
+        i = i + 2
+      elseif next_char == '"' then
+        table.insert(result, '"')
+        i = i + 2
+      elseif next_char == '\\' then
+        table.insert(result, '\\')
+        i = i + 2
+      elseif next_char:match('%d') then
+        local oct = inner:match('^(%d%d%d)', i + 1)
+        if oct then
+          table.insert(result, string.char(tonumber(oct, 8)))
+          i = i + 4
+        else
+          table.insert(result, next_char)
+          i = i + 2
+        end
+      else
+        table.insert(result, next_char)
+        i = i + 2
+      end
+    else
+      table.insert(result, inner:sub(i, i))
+      i = i + 1
+    end
+  end
+  return table.concat(result)
+end
+
 ---@param line string
----@return string?, string?
+---@return string?, string?, string?
 local function parse_file_line(line)
   local old, new = line:match('^R%d*%s+(.-)%s+->%s+(.+)$')
   if old and new then
-    return vim.trim(new), vim.trim(old)
+    return unquote(vim.trim(new)), unquote(vim.trim(old)), 'R'
   end
 
-  local filename = line:match('^[MADRCU?][MADRCU%s]*%s+(.+)$')
+  local status, filename = line:match('^([MADRCU?])[MADRCU%s]*%s+(.+)$')
-  if filename then
+  if status and filename then
-    return vim.trim(filename), nil
+    return unquote(vim.trim(filename)), nil, status
   end
 
-  return nil, nil
+  return nil, nil, nil
 end
 
 ---@param line string
@@ -57,34 +102,34 @@ end
 
 ---@param bufnr integer
 ---@param lnum integer
----@return string?, diffs.FugitiveSection, boolean, string?
+---@return string?, diffs.FugitiveSection, boolean, string?, string?
 function M.get_file_at_line(bufnr, lnum)
   local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
   local current_line = lines[lnum]
 
   if not current_line then
-    return nil, nil, false, nil
+    return nil, nil, false, nil, nil
   end
 
   local section_header = parse_section_header(current_line)
   if section_header then
-    return nil, section_header, true, nil
+    return nil, section_header, true, nil, nil
   end
 
-  local filename, old_filename = parse_file_line(current_line)
+  local filename, old_filename, status = parse_file_line(current_line)
   if filename then
     local section = M.get_section_at_line(bufnr, lnum)
-    return filename, section, false, old_filename
+    return filename, section, false, old_filename, status
   end
 
   local prefix = current_line:sub(1, 1)
   if prefix == '+' or prefix == '-' or prefix == ' ' then
     for i = lnum - 1, 1, -1 do
       local prev_line = lines[i]
-      filename, old_filename = parse_file_line(prev_line)
+      filename, old_filename, status = parse_file_line(prev_line)
       if filename then
         local section = M.get_section_at_line(bufnr, i)
-        return filename, section, false, old_filename
+        return filename, section, false, old_filename, status
       end
       if prev_line:match('^%w+ %(') or prev_line == '' then
         break
@@ -92,7 +137,7 @@ function M.get_file_at_line(bufnr, lnum)
     end
   end
 
-  return nil, nil, false, nil
+  return nil, nil, false, nil, nil
 end
 
 ---@class diffs.HunkPosition
@@ -150,7 +195,7 @@ function M.diff_file_under_cursor(vertical)
   local bufnr = vim.api.nvim_get_current_buf()
   local lnum = vim.api.nvim_win_get_cursor(0)[1]
 
-  local filename, section, is_header, old_filename = M.get_file_at_line(bufnr, lnum)
+  local filename, section, is_header, old_filename, status = M.get_file_at_line(bufnr, lnum)
 
   local repo_root = get_repo_root_from_fugitive(bufnr)
   if not repo_root then
@@ -192,6 +237,7 @@ function M.diff_file_under_cursor(vertical)
     vertical = vertical,
     staged = section == 'staged',
     untracked = section == 'untracked',
+    unmerged = status == 'U',
     old_filepath = old_filepath,
     hunk_position = hunk_position,
   })

lua/diffs/git.lua

@@ -1,13 +1,19 @@
 local M = {}
 
+local repo_root_cache = {}
+
 ---@param filepath string
 ---@return string?
 function M.get_repo_root(filepath)
   local dir = vim.fn.fnamemodify(filepath, ':h')
+  if repo_root_cache[dir] ~= nil then
+    return repo_root_cache[dir]
+  end
   local result = vim.fn.systemlist({ 'git', '-C', dir, 'rev-parse', '--show-toplevel' })
   if vim.v.shell_error ~= 0 then
     return nil
   end
+  repo_root_cache[dir] = result[1]
   return result[1]
 end
 

lua/diffs/highlight.lua

@@ -3,38 +3,6 @@ local M = {}
 local dbg = require('diffs.log').dbg
 local diff = require('diffs.diff')
 
----@param filepath string
----@param from_line integer
----@param count integer
----@return string[]
-local function read_line_range(filepath, from_line, count)
-  if count <= 0 then
-    return {}
-  end
-  local f = io.open(filepath, 'r')
-  if not f then
-    return {}
-  end
-  local result = {}
-  local line_num = 0
-  for line in f:lines() do
-    line_num = line_num + 1
-    if line_num >= from_line then
-      table.insert(result, line)
-      if #result >= count then
-        break
-      end
-    end
-  end
-  f:close()
-  return result
-end
-
-local PRIORITY_CLEAR = 198
-local PRIORITY_SYNTAX = 199
-local PRIORITY_LINE_BG = 200
-local PRIORITY_CHAR_BG = 201
-
 ---@param bufnr integer
 ---@param ns integer
 ---@param hunk diffs.Hunk
@@ -42,8 +10,9 @@ local PRIORITY_CHAR_BG = 201
 ---@param text string
 ---@param lang string
 ---@param context_lines? string[]
+---@param priorities diffs.PrioritiesConfig
 ---@return integer
-local function highlight_text(bufnr, ns, hunk, col_offset, text, lang, context_lines)
+local function highlight_text(bufnr, ns, hunk, col_offset, text, lang, context_lines, priorities)
   local parse_text = text
   if context_lines and #context_lines > 0 then
     parse_text = text .. '\n' .. table.concat(context_lines, '\n')
@@ -77,7 +46,7 @@ local function highlight_text(bufnr, ns, hunk, col_offset, text, lang, context_l
       local buf_sc = col_offset + sc
       local buf_ec = col_offset + ec
 
-      local priority = lang == 'diff' and (tonumber(metadata.priority) or 100) or PRIORITY_SYNTAX
+      local priority = lang == 'diff' and (tonumber(metadata.priority) or 100) or priorities.syntax
 
       pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_sr, buf_sc, {
         end_row = buf_er,
@@ -103,6 +72,7 @@ end
 ---@param line_map table<integer, integer>
 ---@param col_offset integer
 ---@param covered_lines? table<integer, true>
+---@param priorities diffs.PrioritiesConfig
 ---@return integer
 local function highlight_treesitter(
   bufnr,
@@ -111,7 +81,8 @@ local function highlight_treesitter(
   lang,
   line_map,
   col_offset,
-  covered_lines
+  covered_lines,
+  priorities
 )
   local code = table.concat(code_lines, '\n')
   if code == '' then
@@ -152,7 +123,7 @@ local function highlight_treesitter(
           local buf_ec = ec + col_offset
 
           local priority = tree_lang == 'diff' and (tonumber(metadata.priority) or 100)
-            or PRIORITY_SYNTAX
+            or priorities.syntax
 
           pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_sr, buf_sc, {
             end_row = buf_er,
@@ -219,8 +190,17 @@ end
 ---@param code_lines string[]
 ---@param covered_lines? table<integer, true>
 ---@param leading_offset? integer
+---@param priorities diffs.PrioritiesConfig
 ---@return integer
-local function highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines, leading_offset)
+local function highlight_vim_syntax(
+  bufnr,
+  ns,
+  hunk,
+  code_lines,
+  covered_lines,
+  leading_offset,
+  priorities
+)
   local ft = hunk.ft
   if not ft then
     return 0
@@ -238,7 +218,7 @@ local function highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines,
 
   local spans = {}
 
-  vim.api.nvim_buf_call(scratch, function()
+  pcall(vim.api.nvim_buf_call, scratch, function()
     vim.cmd('setlocal syntax=' .. ft)
     vim.cmd('redraw')
 
@@ -256,18 +236,19 @@ local function highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines,
     spans = M.coalesce_syntax_spans(query_fn, code_lines)
   end)
 
-  vim.api.nvim_buf_delete(scratch, { force = true })
+  pcall(vim.api.nvim_buf_delete, scratch, { force = true })
 
   local hunk_line_count = #hunk.lines
+  local col_off = (hunk.prefix_width or 1) - 1
   local extmark_count = 0
   for _, span in ipairs(spans) do
     local adj = span.line - leading_offset
     if adj >= 1 and adj <= hunk_line_count then
       local buf_line = hunk.start_line + adj - 1
-      pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, span.col_start, {
+      pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, span.col_start + col_off, {
-        end_col = span.col_end,
+        end_col = span.col_end + col_off,
         hl_group = span.hl_name,
-        priority = PRIORITY_SYNTAX,
+        priority = priorities.syntax,
       })
       extmark_count = extmark_count + 1
       if covered_lines then
@@ -284,6 +265,8 @@ end
 ---@param hunk diffs.Hunk
 ---@param opts diffs.HunkOpts
 function M.highlight_hunk(bufnr, ns, hunk, opts)
+  local p = opts.highlights.priorities
+  local pw = hunk.prefix_width or 1
   local use_ts = hunk.lang and opts.highlights.treesitter.enabled
   local use_vim = not use_ts and hunk.ft and opts.highlights.vim.enabled
 
@@ -303,21 +286,6 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
   ---@type table<integer, true>
   local covered_lines = {}
 
-  local ctx_cfg = opts.highlights.context
-  local context = (ctx_cfg and ctx_cfg.enabled) and ctx_cfg.lines or 0
-  local leading = {}
-  local trailing = {}
-  if (use_ts or use_vim) and context > 0 and hunk.file_new_start and hunk.repo_root then
-    local filepath = vim.fs.joinpath(hunk.repo_root, hunk.filename)
-    local lead_from = math.max(1, hunk.file_new_start - context)
-    local lead_count = hunk.file_new_start - lead_from
-    if lead_count > 0 then
-      leading = read_line_range(filepath, lead_from, lead_count)
-    end
-    local trail_from = hunk.file_new_start + (hunk.file_new_count or 0)
-    trailing = read_line_range(filepath, trail_from, context)
-  end
-
   local extmark_count = 0
   if use_ts then
     ---@type string[]
@@ -329,20 +297,17 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
     ---@type table<integer, integer>
     local old_map = {}
 
-    for _, pad_line in ipairs(leading) do
-      table.insert(new_code, pad_line)
-      table.insert(old_code, pad_line)
-    end
-
     for i, line in ipairs(hunk.lines) do
-      local prefix = line:sub(1, 1)
+      local prefix = line:sub(1, pw)
-      local stripped = line:sub(2)
+      local stripped = line:sub(pw + 1)
       local buf_line = hunk.start_line + i - 1
+      local has_add = prefix:find('+', 1, true) ~= nil
+      local has_del = prefix:find('-', 1, true) ~= nil
 
-      if prefix == '+' then
+      if has_add and not has_del then
         new_map[#new_code] = buf_line
         table.insert(new_code, stripped)
-      elseif prefix == '-' then
+      elseif has_del and not has_add then
         old_map[#old_code] = buf_line
         table.insert(old_code, stripped)
       else
@@ -352,21 +317,17 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
       end
     end
 
-    for _, pad_line in ipairs(trailing) do
+    extmark_count =
-      table.insert(new_code, pad_line)
+      highlight_treesitter(bufnr, ns, new_code, hunk.lang, new_map, pw, covered_lines, p)
-      table.insert(old_code, pad_line)
-    end
-
-    extmark_count = highlight_treesitter(bufnr, ns, new_code, hunk.lang, new_map, 1, covered_lines)
     extmark_count = extmark_count
-      + highlight_treesitter(bufnr, ns, old_code, hunk.lang, old_map, 1, covered_lines)
+      + highlight_treesitter(bufnr, ns, old_code, hunk.lang, old_map, pw, covered_lines, p)
 
     if hunk.header_context and hunk.header_context_col then
       local header_line = hunk.start_line - 1
       pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, header_line, hunk.header_context_col, {
         end_col = hunk.header_context_col + #hunk.header_context,
         hl_group = 'DiffsClear',
-        priority = PRIORITY_CLEAR,
+        priority = p.clear,
       })
       local header_extmarks = highlight_text(
         bufnr,
@@ -375,7 +336,8 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
         hunk.header_context_col,
         hunk.header_context,
         hunk.lang,
-        new_code
+        new_code,
+        p
       )
       if header_extmarks > 0 then
         dbg('header %s:%d applied %d extmarks', hunk.filename, hunk.start_line, header_extmarks)
@@ -385,16 +347,10 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
   elseif use_vim then
     ---@type string[]
     local code_lines = {}
-    for _, pad_line in ipairs(leading) do
-      table.insert(code_lines, pad_line)
-    end
     for _, line in ipairs(hunk.lines) do
-      table.insert(code_lines, line:sub(2))
+      table.insert(code_lines, line:sub(pw + 1))
     end
-    for _, pad_line in ipairs(trailing) do
+    extmark_count = highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines, 0, p)
-      table.insert(code_lines, pad_line)
-    end
-    extmark_count = highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines, #leading)
   end
 
   if
@@ -409,13 +365,13 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
       header_map[i] = hunk.header_start_line - 1 + i
     end
     extmark_count = extmark_count
-      + highlight_treesitter(bufnr, ns, hunk.header_lines, 'diff', header_map, 0)
+      + highlight_treesitter(bufnr, ns, hunk.header_lines, 'diff', header_map, 0, nil, p)
   end
 
   ---@type diffs.IntraChanges?
   local intra = nil
   local intra_cfg = opts.highlights.intra
-  if intra_cfg and intra_cfg.enabled and #hunk.lines <= intra_cfg.max_lines then
+  if intra_cfg and intra_cfg.enabled and pw == 1 and #hunk.lines <= intra_cfg.max_lines then
     dbg('computing intra for hunk %s:%d (%d lines)', hunk.filename, hunk.start_line, #hunk.lines)
     intra = diff.compute_intra_hunks(hunk.lines, intra_cfg.algorithm)
     if intra then
@@ -449,25 +405,26 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
   for i, line in ipairs(hunk.lines) do
     local buf_line = hunk.start_line + i - 1
     local line_len = #line
-    local prefix = line:sub(1, 1)
+    local prefix = line:sub(1, pw)
-
+    local has_add = prefix:find('+', 1, true) ~= nil
-    local is_diff_line = prefix == '+' or prefix == '-'
+    local has_del = prefix:find('-', 1, true) ~= nil
-    local line_hl = is_diff_line and (prefix == '+' and 'DiffsAdd' or 'DiffsDelete') or nil
+    local is_diff_line = has_add or has_del
-    local number_hl = is_diff_line and (prefix == '+' and 'DiffsAddNr' or 'DiffsDeleteNr') or nil
+    local line_hl = is_diff_line and (has_add and 'DiffsAdd' or 'DiffsDelete') or nil
+    local number_hl = is_diff_line and (has_add and 'DiffsAddNr' or 'DiffsDeleteNr') or nil
 
     if opts.hide_prefix then
       local virt_hl = (opts.highlights.background and line_hl) or nil
       pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, {
-        virt_text = { { ' ', virt_hl } },
+        virt_text = { { string.rep(' ', pw), virt_hl } },
         virt_text_pos = 'overlay',
       })
     end
 
-    if line_len > 1 and covered_lines[buf_line] then
+    if line_len > pw and covered_lines[buf_line] then
-      pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 1, {
+      pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, pw, {
         end_col = line_len,
         hl_group = 'DiffsClear',
-        priority = PRIORITY_CLEAR,
+        priority = p.clear,
       })
     end
 
@@ -476,18 +433,18 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
         end_row = buf_line + 1,
         hl_group = line_hl,
         hl_eol = true,
-        priority = PRIORITY_LINE_BG,
+        priority = p.line_bg,
       })
       if opts.highlights.gutter then
         pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, {
           number_hl_group = number_hl,
-          priority = PRIORITY_LINE_BG,
+          priority = p.line_bg,
         })
       end
     end
 
     if char_spans_by_line[i] then
-      local char_hl = prefix == '+' and 'DiffsAddText' or 'DiffsDeleteText'
+      local char_hl = has_add and 'DiffsAddText' or 'DiffsDeleteText'
       for _, span in ipairs(char_spans_by_line[i]) do
         dbg(
           'char extmark: line=%d buf_line=%d col=%d..%d hl=%s text="%s"',
@@ -501,7 +458,7 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
         local ok, err = pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, span.col_start, {
           end_col = span.col_end,
           hl_group = char_hl,
-          priority = PRIORITY_CHAR_BG,
+          priority = p.char_bg,
         })
         if not ok then
           dbg('char extmark FAILED: %s', err)

lua/diffs/init.lua

@@ -15,6 +15,12 @@
 ---@field enabled boolean
 ---@field lines integer
 
+---@class diffs.PrioritiesConfig
+---@field clear integer
+---@field syntax integer
+---@field line_bg integer
+---@field char_bg integer
+
 ---@class diffs.Highlights
 ---@field background boolean
 ---@field gutter boolean
@@ -24,6 +30,7 @@
 ---@field treesitter diffs.TreesitterConfig
 ---@field vim diffs.VimConfig
 ---@field intra diffs.IntraConfig
+---@field priorities diffs.PrioritiesConfig
 
 ---@class diffs.FugitiveConfig
 ---@field horizontal string|false
@@ -41,6 +48,9 @@
 ---@field enabled boolean
 ---@field disable_diagnostics boolean
 ---@field show_virtual_text boolean
+---@field format_virtual_text? fun(side: string, keymap: string|false): string?
+---@field show_actions boolean
+---@field priority integer
 ---@field keymaps diffs.ConflictKeymaps
 
 ---@class diffs.Config
@@ -119,6 +129,12 @@ local default_config = {
       algorithm = 'default',
       max_lines = 500,
     },
+    priorities = {
+      clear = 198,
+      syntax = 199,
+      line_bg = 200,
+      char_bg = 201,
+    },
   },
   fugitive = {
     horizontal = 'du',
@@ -128,6 +144,8 @@ local default_config = {
     enabled = true,
     disable_diagnostics = true,
     show_virtual_text = true,
+    show_actions = false,
+    priority = 200,
     keymaps = {
       ours = 'doo',
       theirs = 'dot',
@@ -200,7 +218,9 @@ local function create_debounced_highlight(bufnr)
           timer = nil
           t:close()
         end
-        highlight_buffer(bufnr)
+        if vim.api.nvim_buf_is_valid(bufnr) then
+          highlight_buffer(bufnr)
+        end
       end)
     )
   end
@@ -274,6 +294,7 @@ local function compute_highlight_groups()
   vim.api.nvim_set_hl(0, 'DiffsConflictTheirs', { default = true, bg = blended_theirs })
   vim.api.nvim_set_hl(0, 'DiffsConflictBase', { default = true, bg = blended_base })
   vim.api.nvim_set_hl(0, 'DiffsConflictMarker', { default = true, fg = 0x808080, bold = true })
+  vim.api.nvim_set_hl(0, 'DiffsConflictActions', { default = true, fg = 0x808080 })
   vim.api.nvim_set_hl(
     0,
     'DiffsConflictOursNr',
@@ -322,6 +343,7 @@ local function init()
       ['highlights.treesitter'] = { opts.highlights.treesitter, 'table', true },
       ['highlights.vim'] = { opts.highlights.vim, 'table', true },
       ['highlights.intra'] = { opts.highlights.intra, 'table', true },
+      ['highlights.priorities'] = { opts.highlights.priorities, 'table', true },
     })
 
     if opts.highlights.context then
@@ -362,6 +384,15 @@ local function init()
         ['highlights.intra.max_lines'] = { opts.highlights.intra.max_lines, 'number', true },
       })
     end
+
+    if opts.highlights.priorities then
+      vim.validate({
+        ['highlights.priorities.clear'] = { opts.highlights.priorities.clear, 'number', true },
+        ['highlights.priorities.syntax'] = { opts.highlights.priorities.syntax, 'number', true },
+        ['highlights.priorities.line_bg'] = { opts.highlights.priorities.line_bg, 'number', true },
+        ['highlights.priorities.char_bg'] = { opts.highlights.priorities.char_bg, 'number', true },
+      })
+    end
   end
 
   if opts.fugitive then
@@ -388,6 +419,9 @@ local function init()
       ['conflict.enabled'] = { opts.conflict.enabled, 'boolean', true },
       ['conflict.disable_diagnostics'] = { opts.conflict.disable_diagnostics, 'boolean', true },
       ['conflict.show_virtual_text'] = { opts.conflict.show_virtual_text, 'boolean', true },
+      ['conflict.format_virtual_text'] = { opts.conflict.format_virtual_text, 'function', true },
+      ['conflict.show_actions'] = { opts.conflict.show_actions, 'boolean', true },
+      ['conflict.priority'] = { opts.conflict.priority, 'number', true },
       ['conflict.keymaps'] = { opts.conflict.keymaps, 'table', true },
     })
 
@@ -449,6 +483,17 @@ local function init()
   then
     error('diffs: highlights.blend_alpha must be >= 0 and <= 1')
   end
+  if opts.highlights and opts.highlights.priorities then
+    for _, key in ipairs({ 'clear', 'syntax', 'line_bg', 'char_bg' }) do
+      local v = opts.highlights.priorities[key]
+      if v and v < 0 then
+        error('diffs: highlights.priorities.' .. key .. ' must be >= 0')
+      end
+    end
+  end
+  if opts.conflict and opts.conflict.priority and opts.conflict.priority < 0 then
+    error('diffs: conflict.priority must be >= 0')
+  end
 
   config = vim.tbl_deep_extend('force', default_config, opts)
   log.set_enabled(config.debug)

lua/diffs/lib.lua

@@ -8,6 +8,9 @@ local cached_handle = nil
 ---@type boolean
 local download_in_progress = false
 
+---@type fun(handle: table?)[]
+local pending_callbacks = {}
+
 ---@return string
 local function get_os()
   local os_name = jit.os:lower()
@@ -164,9 +167,10 @@ function M.ensure(callback)
     return
   end
 
+  table.insert(pending_callbacks, callback)
+
   if download_in_progress then
-    dbg('download already in progress')
+    dbg('download already in progress, queued callback')
-    callback(nil)
     return
   end
 
@@ -192,21 +196,25 @@ function M.ensure(callback)
   vim.system(cmd, {}, function(result)
     download_in_progress = false
     vim.schedule(function()
+      local handle = nil
       if result.code ~= 0 then
         vim.notify('[diffs] failed to download libvscode_diff', vim.log.levels.WARN)
         dbg('curl failed: %s', result.stderr or '')
-        callback(nil)
+      else
-        return
+        local f = io.open(version_path(), 'w')
+        if f then
+          f:write(EXPECTED_VERSION)
+          f:close()
+        end
+        vim.notify('[diffs] libvscode_diff downloaded', vim.log.levels.INFO)
+        handle = M.load()
       end
 
-      local f = io.open(version_path(), 'w')
+      local cbs = pending_callbacks
-      if f then
+      pending_callbacks = {}
-        f:write(EXPECTED_VERSION)
+      for _, cb in ipairs(cbs) do
-        f:close()
+        cb(handle)
       end
-
-      vim.notify('[diffs] libvscode_diff downloaded', vim.log.levels.INFO)
-      callback(M.load())
     end)
   end)
 end

lua/diffs/merge.lua

@@ -0,0 +1,418 @@
+local M = {}
+
+local conflict = require('diffs.conflict')
+
+local ns = vim.api.nvim_create_namespace('diffs-merge')
+
+---@type table<integer, table<integer, true>>
+local resolved_hunks = {}
+
+---@class diffs.MergeHunkInfo
+---@field index integer
+---@field start_line integer
+---@field end_line integer
+---@field del_lines string[]
+---@field add_lines string[]
+
+---@param bufnr integer
+---@return diffs.MergeHunkInfo[]
+function M.parse_hunks(bufnr)
+  local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
+  local hunks = {}
+  local current = nil
+
+  for i, line in ipairs(lines) do
+    local idx = i - 1
+    if line:match('^@@') then
+      if current then
+        current.end_line = idx - 1
+        table.insert(hunks, current)
+      end
+      current = {
+        index = #hunks + 1,
+        start_line = idx,
+        end_line = idx,
+        del_lines = {},
+        add_lines = {},
+      }
+    elseif current then
+      local prefix = line:sub(1, 1)
+      if prefix == '-' then
+        table.insert(current.del_lines, line:sub(2))
+      elseif prefix == '+' then
+        table.insert(current.add_lines, line:sub(2))
+      elseif prefix ~= ' ' and prefix ~= '\\' then
+        current.end_line = idx - 1
+        table.insert(hunks, current)
+        current = nil
+      end
+      if current then
+        current.end_line = idx
+      end
+    end
+  end
+
+  if current then
+    table.insert(hunks, current)
+  end
+
+  return hunks
+end
+
+---@param bufnr integer
+---@return diffs.MergeHunkInfo?
+function M.find_hunk_at_cursor(bufnr)
+  local hunks = M.parse_hunks(bufnr)
+  local cursor_line = vim.api.nvim_win_get_cursor(0)[1] - 1
+
+  for _, hunk in ipairs(hunks) do
+    if cursor_line >= hunk.start_line and cursor_line <= hunk.end_line then
+      return hunk
+    end
+  end
+
+  return nil
+end
+
+---@param hunk diffs.MergeHunkInfo
+---@param working_bufnr integer
+---@return diffs.ConflictRegion?
+function M.match_hunk_to_conflict(hunk, working_bufnr)
+  local working_lines = vim.api.nvim_buf_get_lines(working_bufnr, 0, -1, false)
+  local regions = conflict.parse(working_lines)
+
+  for _, region in ipairs(regions) do
+    local ours_lines = {}
+    for line = region.ours_start + 1, region.ours_end do
+      table.insert(ours_lines, working_lines[line])
+    end
+
+    if #ours_lines == #hunk.del_lines then
+      local match = true
+      for j = 1, #ours_lines do
+        if ours_lines[j] ~= hunk.del_lines[j] then
+          match = false
+          break
+        end
+      end
+      if match then
+        return region
+      end
+    end
+  end
+
+  return nil
+end
+
+---@param diff_bufnr integer
+---@return integer?
+function M.get_or_load_working_buf(diff_bufnr)
+  local ok, working_path = pcall(vim.api.nvim_buf_get_var, diff_bufnr, 'diffs_working_path')
+  if not ok or not working_path then
+    return nil
+  end
+
+  local existing = vim.fn.bufnr(working_path)
+  if existing ~= -1 then
+    return existing
+  end
+
+  local bufnr = vim.fn.bufadd(working_path)
+  vim.fn.bufload(bufnr)
+  return bufnr
+end
+
+---@param diff_bufnr integer
+---@param hunk_index integer
+local function mark_resolved(diff_bufnr, hunk_index)
+  if not resolved_hunks[diff_bufnr] then
+    resolved_hunks[diff_bufnr] = {}
+  end
+  resolved_hunks[diff_bufnr][hunk_index] = true
+end
+
+---@param diff_bufnr integer
+---@param hunk_index integer
+---@return boolean
+function M.is_resolved(diff_bufnr, hunk_index)
+  return resolved_hunks[diff_bufnr] and resolved_hunks[diff_bufnr][hunk_index] or false
+end
+
+---@param diff_bufnr integer
+---@param hunk diffs.MergeHunkInfo
+local function add_resolved_virtual_text(diff_bufnr, hunk)
+  pcall(vim.api.nvim_buf_set_extmark, diff_bufnr, ns, hunk.start_line, 0, {
+    virt_text = { { ' (resolved)', 'Comment' } },
+    virt_text_pos = 'eol',
+  })
+end
+
+---@param bufnr integer
+---@param config diffs.ConflictConfig
+function M.resolve_ours(bufnr, config)
+  local hunk = M.find_hunk_at_cursor(bufnr)
+  if not hunk then
+    return
+  end
+  if M.is_resolved(bufnr, hunk.index) then
+    vim.notify('[diffs.nvim]: hunk already resolved', vim.log.levels.INFO)
+    return
+  end
+  local working_bufnr = M.get_or_load_working_buf(bufnr)
+  if not working_bufnr then
+    return
+  end
+  local region = M.match_hunk_to_conflict(hunk, working_bufnr)
+  if not region then
+    vim.notify('[diffs.nvim]: hunk does not correspond to a conflict region', vim.log.levels.INFO)
+    return
+  end
+  local lines = vim.api.nvim_buf_get_lines(working_bufnr, region.ours_start, region.ours_end, false)
+  conflict.replace_region(working_bufnr, region, lines)
+  conflict.refresh(working_bufnr, config)
+  mark_resolved(bufnr, hunk.index)
+  add_resolved_virtual_text(bufnr, hunk)
+end
+
+---@param bufnr integer
+---@param config diffs.ConflictConfig
+function M.resolve_theirs(bufnr, config)
+  local hunk = M.find_hunk_at_cursor(bufnr)
+  if not hunk then
+    return
+  end
+  if M.is_resolved(bufnr, hunk.index) then
+    vim.notify('[diffs.nvim]: hunk already resolved', vim.log.levels.INFO)
+    return
+  end
+  local working_bufnr = M.get_or_load_working_buf(bufnr)
+  if not working_bufnr then
+    return
+  end
+  local region = M.match_hunk_to_conflict(hunk, working_bufnr)
+  if not region then
+    vim.notify('[diffs.nvim]: hunk does not correspond to a conflict region', vim.log.levels.INFO)
+    return
+  end
+  local lines =
+    vim.api.nvim_buf_get_lines(working_bufnr, region.theirs_start, region.theirs_end, false)
+  conflict.replace_region(working_bufnr, region, lines)
+  conflict.refresh(working_bufnr, config)
+  mark_resolved(bufnr, hunk.index)
+  add_resolved_virtual_text(bufnr, hunk)
+end
+
+---@param bufnr integer
+---@param config diffs.ConflictConfig
+function M.resolve_both(bufnr, config)
+  local hunk = M.find_hunk_at_cursor(bufnr)
+  if not hunk then
+    return
+  end
+  if M.is_resolved(bufnr, hunk.index) then
+    vim.notify('[diffs.nvim]: hunk already resolved', vim.log.levels.INFO)
+    return
+  end
+  local working_bufnr = M.get_or_load_working_buf(bufnr)
+  if not working_bufnr then
+    return
+  end
+  local region = M.match_hunk_to_conflict(hunk, working_bufnr)
+  if not region then
+    vim.notify('[diffs.nvim]: hunk does not correspond to a conflict region', vim.log.levels.INFO)
+    return
+  end
+  local ours = vim.api.nvim_buf_get_lines(working_bufnr, region.ours_start, region.ours_end, false)
+  local theirs =
+    vim.api.nvim_buf_get_lines(working_bufnr, region.theirs_start, region.theirs_end, false)
+  local combined = {}
+  for _, l in ipairs(ours) do
+    table.insert(combined, l)
+  end
+  for _, l in ipairs(theirs) do
+    table.insert(combined, l)
+  end
+  conflict.replace_region(working_bufnr, region, combined)
+  conflict.refresh(working_bufnr, config)
+  mark_resolved(bufnr, hunk.index)
+  add_resolved_virtual_text(bufnr, hunk)
+end
+
+---@param bufnr integer
+---@param config diffs.ConflictConfig
+function M.resolve_none(bufnr, config)
+  local hunk = M.find_hunk_at_cursor(bufnr)
+  if not hunk then
+    return
+  end
+  if M.is_resolved(bufnr, hunk.index) then
+    vim.notify('[diffs.nvim]: hunk already resolved', vim.log.levels.INFO)
+    return
+  end
+  local working_bufnr = M.get_or_load_working_buf(bufnr)
+  if not working_bufnr then
+    return
+  end
+  local region = M.match_hunk_to_conflict(hunk, working_bufnr)
+  if not region then
+    vim.notify('[diffs.nvim]: hunk does not correspond to a conflict region', vim.log.levels.INFO)
+    return
+  end
+  conflict.replace_region(working_bufnr, region, {})
+  conflict.refresh(working_bufnr, config)
+  mark_resolved(bufnr, hunk.index)
+  add_resolved_virtual_text(bufnr, hunk)
+end
+
+---@param bufnr integer
+function M.goto_next(bufnr)
+  local hunks = M.parse_hunks(bufnr)
+  if #hunks == 0 then
+    return
+  end
+
+  local working_bufnr = M.get_or_load_working_buf(bufnr)
+  if not working_bufnr then
+    return
+  end
+
+  local cursor_line = vim.api.nvim_win_get_cursor(0)[1] - 1
+
+  local candidates = {}
+  for _, hunk in ipairs(hunks) do
+    if not M.is_resolved(bufnr, hunk.index) then
+      if M.match_hunk_to_conflict(hunk, working_bufnr) then
+        table.insert(candidates, hunk)
+      end
+    end
+  end
+
+  if #candidates == 0 then
+    return
+  end
+
+  for _, hunk in ipairs(candidates) do
+    if hunk.start_line > cursor_line then
+      vim.api.nvim_win_set_cursor(0, { hunk.start_line + 1, 0 })
+      return
+    end
+  end
+
+  vim.notify('[diffs.nvim]: wrapped to first hunk', vim.log.levels.INFO)
+  vim.api.nvim_win_set_cursor(0, { candidates[1].start_line + 1, 0 })
+end
+
+---@param bufnr integer
+function M.goto_prev(bufnr)
+  local hunks = M.parse_hunks(bufnr)
+  if #hunks == 0 then
+    return
+  end
+
+  local working_bufnr = M.get_or_load_working_buf(bufnr)
+  if not working_bufnr then
+    return
+  end
+
+  local cursor_line = vim.api.nvim_win_get_cursor(0)[1] - 1
+
+  local candidates = {}
+  for _, hunk in ipairs(hunks) do
+    if not M.is_resolved(bufnr, hunk.index) then
+      if M.match_hunk_to_conflict(hunk, working_bufnr) then
+        table.insert(candidates, hunk)
+      end
+    end
+  end
+
+  if #candidates == 0 then
+    return
+  end
+
+  for i = #candidates, 1, -1 do
+    if candidates[i].start_line < cursor_line then
+      vim.api.nvim_win_set_cursor(0, { candidates[i].start_line + 1, 0 })
+      return
+    end
+  end
+
+  vim.notify('[diffs.nvim]: wrapped to last hunk', vim.log.levels.INFO)
+  vim.api.nvim_win_set_cursor(0, { candidates[#candidates].start_line + 1, 0 })
+end
+
+---@param bufnr integer
+---@param config diffs.ConflictConfig
+local function apply_hunk_hints(bufnr, config)
+  if not config.show_virtual_text then
+    return
+  end
+
+  local hunks = M.parse_hunks(bufnr)
+  for _, hunk in ipairs(hunks) do
+    if M.is_resolved(bufnr, hunk.index) then
+      add_resolved_virtual_text(bufnr, hunk)
+    else
+      local parts = {}
+      local actions = {
+        { 'current', config.keymaps.ours },
+        { 'incoming', config.keymaps.theirs },
+        { 'both', config.keymaps.both },
+        { 'none', config.keymaps.none },
+      }
+      for _, action in ipairs(actions) do
+        if action[2] then
+          if #parts > 0 then
+            table.insert(parts, { ' | ', 'Comment' })
+          end
+          table.insert(parts, { ('%s: %s'):format(action[2], action[1]), 'Comment' })
+        end
+      end
+      if #parts > 0 then
+        pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, hunk.start_line, 0, {
+          virt_text = parts,
+          virt_text_pos = 'eol',
+        })
+      end
+    end
+  end
+end
+
+---@param bufnr integer
+---@param config diffs.ConflictConfig
+function M.setup_keymaps(bufnr, config)
+  resolved_hunks[bufnr] = nil
+  vim.api.nvim_buf_clear_namespace(bufnr, ns, 0, -1)
+
+  local km = config.keymaps
+
+  local maps = {
+    { km.ours, '<Plug>(diffs-merge-ours)' },
+    { km.theirs, '<Plug>(diffs-merge-theirs)' },
+    { km.both, '<Plug>(diffs-merge-both)' },
+    { km.none, '<Plug>(diffs-merge-none)' },
+    { km.next, '<Plug>(diffs-merge-next)' },
+    { km.prev, '<Plug>(diffs-merge-prev)' },
+  }
+
+  for _, map in ipairs(maps) do
+    if map[1] then
+      vim.keymap.set('n', map[1], map[2], { buffer = bufnr })
+    end
+  end
+
+  apply_hunk_hints(bufnr, config)
+
+  vim.api.nvim_create_autocmd('BufWipeout', {
+    buffer = bufnr,
+    callback = function()
+      resolved_hunks[bufnr] = nil
+    end,
+  })
+end
+
+---@return integer
+function M.get_namespace()
+  return ns
+end
+
+return M

lua/diffs/parser.lua

@@ -12,6 +12,7 @@
 ---@field file_old_count integer?
 ---@field file_new_start integer?
 ---@field file_new_count integer?
+---@field prefix_width integer
 ---@field repo_root string?
 
 local M = {}
@@ -133,6 +134,8 @@ function M.parse_buffer(bufnr)
   local hunk_lines = {}
   ---@type integer?
   local hunk_count = nil
+  ---@type integer
+  local hunk_prefix_width = 1
   ---@type integer?
   local header_start = nil
   ---@type string[]
@@ -156,6 +159,7 @@ function M.parse_buffer(bufnr)
         header_context = hunk_header_context,
         header_context_col = hunk_header_context_col,
         lines = hunk_lines,
+        prefix_width = hunk_prefix_width,
         file_old_start = file_old_start,
         file_old_count = file_old_count,
         file_new_start = file_new_start,
@@ -179,7 +183,7 @@ function M.parse_buffer(bufnr)
   end
 
   for i, line in ipairs(lines) do
-    local filename = line:match('^[MADRC%?!]%s+(.+)$') or line:match('^diff %-%-git a/.+ b/(.+)$')
+    local filename = line:match('^[MADRCU%?!]%s+(.+)$') or line:match('^diff %-%-git a/.+ b/(.+)$')
     if filename then
       flush_hunk()
       current_filename = filename
@@ -191,22 +195,33 @@ function M.parse_buffer(bufnr)
         dbg('file: %s -> ft: %s (no ts parser)', filename, current_ft)
       end
       hunk_count = 0
+      hunk_prefix_width = 1
       header_start = i
       header_lines = {}
-    elseif line:match('^@@.-@@') then
+    elseif line:match('^@@+') then
       flush_hunk()
       hunk_start = i
-      local hs, hc, hs2, hc2 = line:match('^@@ %-(%d+),?(%d*) %+(%d+),?(%d*) @@')
+      local at_prefix = line:match('^(@@+)')
-      if hs then
+      hunk_prefix_width = #at_prefix - 1
-        file_old_start = tonumber(hs)
+      if #at_prefix == 2 then
-        file_old_count = tonumber(hc) or 1
+        local hs, hc, hs2, hc2 = line:match('^@@ %-(%d+),?(%d*) %+(%d+),?(%d*) @@')
-        file_new_start = tonumber(hs2)
+        if hs then
-        file_new_count = tonumber(hc2) or 1
+          file_old_start = tonumber(hs)
+          file_old_count = tonumber(hc) or 1
+          file_new_start = tonumber(hs2)
+          file_new_count = tonumber(hc2) or 1
+        end
+      else
+        local hs2, hc2 = line:match('%+(%d+),?(%d*) @@')
+        if hs2 then
+          file_new_start = tonumber(hs2)
+          file_new_count = tonumber(hc2) or 1
+        end
       end
-      local prefix, context = line:match('^(@@.-@@%s*)(.*)')
+      local at_end, context = line:match('^(@@+.-@@+%s*)(.*)')
       if context and context ~= '' then
         hunk_header_context = context
-        hunk_header_context_col = #prefix
+        hunk_header_context_col = #at_end
       end
       if hunk_count then
         hunk_count = hunk_count + 1

plugin/diffs.lua

@@ -57,3 +57,53 @@ end, { desc = 'Unified diff (horizontal)' })
 vim.keymap.set('n', '<Plug>(diffs-gvdiff)', function()
   cmds.gdiff(nil, true)
 end, { desc = 'Unified diff (vertical)' })
+
+local function conflict_action(fn)
+  local bufnr = vim.api.nvim_get_current_buf()
+  local config = require('diffs').get_conflict_config()
+  fn(bufnr, config)
+end
+
+vim.keymap.set('n', '<Plug>(diffs-conflict-ours)', function()
+  conflict_action(require('diffs.conflict').resolve_ours)
+end, { desc = 'Accept current (ours) change' })
+vim.keymap.set('n', '<Plug>(diffs-conflict-theirs)', function()
+  conflict_action(require('diffs.conflict').resolve_theirs)
+end, { desc = 'Accept incoming (theirs) change' })
+vim.keymap.set('n', '<Plug>(diffs-conflict-both)', function()
+  conflict_action(require('diffs.conflict').resolve_both)
+end, { desc = 'Accept both changes' })
+vim.keymap.set('n', '<Plug>(diffs-conflict-none)', function()
+  conflict_action(require('diffs.conflict').resolve_none)
+end, { desc = 'Reject both changes' })
+vim.keymap.set('n', '<Plug>(diffs-conflict-next)', function()
+  require('diffs.conflict').goto_next(vim.api.nvim_get_current_buf())
+end, { desc = 'Jump to next conflict' })
+vim.keymap.set('n', '<Plug>(diffs-conflict-prev)', function()
+  require('diffs.conflict').goto_prev(vim.api.nvim_get_current_buf())
+end, { desc = 'Jump to previous conflict' })
+
+local function merge_action(fn)
+  local bufnr = vim.api.nvim_get_current_buf()
+  local config = require('diffs').get_conflict_config()
+  fn(bufnr, config)
+end
+
+vim.keymap.set('n', '<Plug>(diffs-merge-ours)', function()
+  merge_action(require('diffs.merge').resolve_ours)
+end, { desc = 'Accept ours in merge diff' })
+vim.keymap.set('n', '<Plug>(diffs-merge-theirs)', function()
+  merge_action(require('diffs.merge').resolve_theirs)
+end, { desc = 'Accept theirs in merge diff' })
+vim.keymap.set('n', '<Plug>(diffs-merge-both)', function()
+  merge_action(require('diffs.merge').resolve_both)
+end, { desc = 'Accept both in merge diff' })
+vim.keymap.set('n', '<Plug>(diffs-merge-none)', function()
+  merge_action(require('diffs.merge').resolve_none)
+end, { desc = 'Reject both in merge diff' })
+vim.keymap.set('n', '<Plug>(diffs-merge-next)', function()
+  require('diffs.merge').goto_next(vim.api.nvim_get_current_buf())
+end, { desc = 'Jump to next conflict hunk' })
+vim.keymap.set('n', '<Plug>(diffs-merge-prev)', function()
+  require('diffs.merge').goto_prev(vim.api.nvim_get_current_buf())
+end, { desc = 'Jump to previous conflict hunk' })

spec/commands_spec.lua

@@ -40,6 +40,78 @@ describe('commands', function()
     end)
   end)
 
+  describe('filter_combined_diffs', function()
+    it('strips diff --cc entries entirely', function()
+      local lines = {
+        'diff --cc main.lua',
+        'index d13ab94,b113aee..0000000',
+        '--- a/main.lua',
+        '+++ b/main.lua',
+        '@@@ -1,7 -1,7 +1,11 @@@',
+        '  local M = {}',
+        '++<<<<<<< HEAD',
+        ' +  return 1',
+        '++=======',
+        '+   return 2',
+        '++>>>>>>> theirs',
+        '  end',
+      }
+      local result = commands.filter_combined_diffs(lines)
+      assert.are.equal(0, #result)
+    end)
+
+    it('preserves diff --git entries', function()
+      local lines = {
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,3 +1,3 @@',
+        ' local M = {}',
+        '-local x = 1',
+        '+local x = 2',
+        ' return M',
+      }
+      local result = commands.filter_combined_diffs(lines)
+      assert.are.equal(8, #result)
+      assert.are.same(lines, result)
+    end)
+
+    it('strips combined but keeps unified in mixed output', function()
+      local lines = {
+        'diff --cc conflict.lua',
+        'index aaa,bbb..000',
+        '@@@ -1,1 -1,1 +1,5 @@@',
+        '++<<<<<<< HEAD',
+        'diff --git a/clean.lua b/clean.lua',
+        '--- a/clean.lua',
+        '+++ b/clean.lua',
+        '@@ -1,1 +1,1 @@',
+        '-old',
+        '+new',
+      }
+      local result = commands.filter_combined_diffs(lines)
+      assert.are.equal(6, #result)
+      assert.are.equal('diff --git a/clean.lua b/clean.lua', result[1])
+      assert.are.equal('+new', result[6])
+    end)
+
+    it('returns empty for empty input', function()
+      local result = commands.filter_combined_diffs({})
+      assert.are.equal(0, #result)
+    end)
+
+    it('returns empty when all entries are combined', function()
+      local lines = {
+        'diff --cc a.lua',
+        'some content',
+        'diff --cc b.lua',
+        'more content',
+      }
+      local result = commands.filter_combined_diffs(lines)
+      assert.are.equal(0, #result)
+    end)
+  end)
+
   describe('find_hunk_line', function()
     it('finds matching @@ header and returns target line', function()
       local diff_lines = {

spec/conflict_spec.lua

@@ -6,6 +6,7 @@ local function default_config(overrides)
     enabled = true,
     disable_diagnostics = false,
     show_virtual_text = true,
+    show_actions = false,
     keymaps = {
       ours = 'doo',
       theirs = 'dot',
@@ -234,29 +235,6 @@ describe('conflict', function()
       helpers.delete_buffer(bufnr)
     end)
 
-    it('does not apply virtual text when disabled', function()
-      local bufnr = create_file_buffer({
-        '<<<<<<< HEAD',
-        'local x = 1',
-        '=======',
-        'local x = 2',
-        '>>>>>>> feature',
-      })
-
-      conflict.attach(bufnr, default_config({ show_virtual_text = false }))
-
-      local extmarks = get_extmarks(bufnr)
-      local virt_text_count = 0
-      for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].virt_text then
-          virt_text_count = virt_text_count + 1
-        end
-      end
-      assert.are.equal(0, virt_text_count)
-
-      helpers.delete_buffer(bufnr)
-    end)
-
     it('applies number_hl_group to content lines', function()
       local bufnr = create_file_buffer({
         '<<<<<<< HEAD',
@@ -531,6 +509,33 @@ describe('conflict', function()
       helpers.delete_buffer(bufnr)
     end)
 
+    it('goto_next notifies on wrap-around', function()
+      local bufnr = create_file_buffer({
+        '<<<<<<< HEAD',
+        'a',
+        '=======',
+        'b',
+        '>>>>>>> feat',
+      })
+      vim.api.nvim_set_current_buf(bufnr)
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      local notified = false
+      local orig_notify = vim.notify
+      vim.notify = function(msg)
+        if msg:match('wrapped to first conflict') then
+          notified = true
+        end
+      end
+
+      conflict.goto_next(bufnr)
+      vim.notify = orig_notify
+
+      assert.is_true(notified)
+
+      helpers.delete_buffer(bufnr)
+    end)
+
     it('goto_prev jumps to previous conflict', function()
       local bufnr = create_file_buffer({
         '<<<<<<< HEAD',
@@ -575,6 +580,33 @@ describe('conflict', function()
       helpers.delete_buffer(bufnr)
     end)
 
+    it('goto_prev notifies on wrap-around', function()
+      local bufnr = create_file_buffer({
+        '<<<<<<< HEAD',
+        'a',
+        '=======',
+        'b',
+        '>>>>>>> feat',
+      })
+      vim.api.nvim_set_current_buf(bufnr)
+      vim.api.nvim_win_set_cursor(0, { 1, 0 })
+
+      local notified = false
+      local orig_notify = vim.notify
+      vim.notify = function(msg)
+        if msg:match('wrapped to last conflict') then
+          notified = true
+        end
+      end
+
+      conflict.goto_prev(bufnr)
+      vim.notify = orig_notify
+
+      assert.is_true(notified)
+
+      helpers.delete_buffer(bufnr)
+    end)
+
     it('goto_next does nothing with no conflicts', function()
       local bufnr = create_file_buffer({ 'normal line' })
       vim.api.nvim_set_current_buf(bufnr)
@@ -685,4 +717,158 @@ describe('conflict', function()
       helpers.delete_buffer(bufnr)
     end)
   end)
+
+  describe('virtual text formatting', function()
+    after_each(function()
+      conflict.detach(vim.api.nvim_get_current_buf())
+    end)
+
+    it('default labels show current and incoming without keymaps', function()
+      local bufnr = create_file_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      })
+
+      conflict.attach(bufnr, default_config())
+
+      local extmarks = get_extmarks(bufnr)
+      local labels = {}
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].virt_text then
+          table.insert(labels, mark[4].virt_text[1][1])
+        end
+      end
+      assert.are.equal(2, #labels)
+      assert.are.equal(' (current)', labels[1])
+      assert.are.equal(' (incoming)', labels[2])
+
+      helpers.delete_buffer(bufnr)
+    end)
+
+    it('uses custom format_virtual_text function', function()
+      local bufnr = create_file_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      })
+
+      conflict.attach(
+        bufnr,
+        default_config({
+          format_virtual_text = function(side)
+            return side == 'ours' and 'OURS' or 'THEIRS'
+          end,
+        })
+      )
+
+      local extmarks = get_extmarks(bufnr)
+      local labels = {}
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].virt_text then
+          table.insert(labels, mark[4].virt_text[1][1])
+        end
+      end
+      assert.are.equal(2, #labels)
+      assert.are.equal(' (OURS)', labels[1])
+      assert.are.equal(' (THEIRS)', labels[2])
+
+      helpers.delete_buffer(bufnr)
+    end)
+
+    it('hides label when format_virtual_text returns nil', function()
+      local bufnr = create_file_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      })
+
+      conflict.attach(
+        bufnr,
+        default_config({
+          format_virtual_text = function()
+            return nil
+          end,
+        })
+      )
+
+      local extmarks = get_extmarks(bufnr)
+      local virt_text_count = 0
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].virt_text then
+          virt_text_count = virt_text_count + 1
+        end
+      end
+      assert.are.equal(0, virt_text_count)
+
+      helpers.delete_buffer(bufnr)
+    end)
+  end)
+
+  describe('action lines', function()
+    after_each(function()
+      conflict.detach(vim.api.nvim_get_current_buf())
+    end)
+
+    it('adds virt_lines when show_actions is true', function()
+      local bufnr = create_file_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      })
+
+      conflict.attach(bufnr, default_config({ show_actions = true }))
+
+      local extmarks = get_extmarks(bufnr)
+      local virt_lines_count = 0
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].virt_lines then
+          virt_lines_count = virt_lines_count + 1
+        end
+      end
+      assert.are.equal(1, virt_lines_count)
+
+      helpers.delete_buffer(bufnr)
+    end)
+
+    it('omits disabled keymaps from action line', function()
+      local bufnr = create_file_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      })
+
+      conflict.attach(
+        bufnr,
+        default_config({ show_actions = true, keymaps = { both = false, none = false } })
+      )
+
+      local extmarks = get_extmarks(bufnr)
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].virt_lines then
+          local line = mark[4].virt_lines[1]
+          local text = ''
+          for _, chunk in ipairs(line) do
+            text = text .. chunk[1]
+          end
+          assert.is_truthy(text:find('Current'))
+          assert.is_truthy(text:find('Incoming'))
+          assert.is_falsy(text:find('Both'))
+          assert.is_falsy(text:find('None'))
+        end
+      end
+
+      helpers.delete_buffer(bufnr)
+    end)
+  end)
 end)

spec/fugitive_spec.lua

@@ -87,28 +87,6 @@ describe('fugitive', function()
       vim.api.nvim_buf_delete(buf, { force = true })
     end)
 
-    it('parses added file', function()
-      local buf = create_status_buffer({
-        'Staged (1)',
-        'A  newfile.lua',
-      })
-      local filename, section = fugitive.get_file_at_line(buf, 2)
-      assert.equals('newfile.lua', filename)
-      assert.equals('staged', section)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
-    it('parses deleted file', function()
-      local buf = create_status_buffer({
-        'Staged (1)',
-        'D  oldfile.lua',
-      })
-      local filename, section = fugitive.get_file_at_line(buf, 2)
-      assert.equals('oldfile.lua', filename)
-      assert.equals('staged', section)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
     it('parses renamed file and returns both names', function()
       local buf = create_status_buffer({
         'Staged (1)',
@@ -157,28 +135,6 @@ describe('fugitive', function()
       vim.api.nvim_buf_delete(buf, { force = true })
     end)
 
-    it('handles renamed file in subdirectory', function()
-      local buf = create_status_buffer({
-        'Staged (1)',
-        'R  src/old.lua -> src/new.lua',
-      })
-      local filename, _, _, old_filename = fugitive.get_file_at_line(buf, 2)
-      assert.equals('src/new.lua', filename)
-      assert.equals('src/old.lua', old_filename)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
-    it('handles renamed file moved to different directory', function()
-      local buf = create_status_buffer({
-        'Staged (1)',
-        'R  old/file.lua -> new/file.lua',
-      })
-      local filename, _, _, old_filename = fugitive.get_file_at_line(buf, 2)
-      assert.equals('new/file.lua', filename)
-      assert.equals('old/file.lua', old_filename)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
     it('KNOWN LIMITATION: filename containing arrow parsed incorrectly', function()
       local buf = create_status_buffer({
         'Staged (1)',
@@ -190,77 +146,54 @@ describe('fugitive', function()
       vim.api.nvim_buf_delete(buf, { force = true })
     end)
 
-    it('handles double extensions', function()
+    it('unquotes git-quoted filenames with spaces', function()
+      local buf = create_status_buffer({
+        'Unstaged (1)',
+        'M  "path with spaces/file.lua"',
+      })
+      local filename = fugitive.get_file_at_line(buf, 2)
+      assert.equals('path with spaces/file.lua', filename)
+      vim.api.nvim_buf_delete(buf, { force = true })
+    end)
+
+    it('unquotes escaped quotes in filenames', function()
+      local buf = create_status_buffer({
+        'Unstaged (1)',
+        'M  "file\\"name.lua"',
+      })
+      local filename = fugitive.get_file_at_line(buf, 2)
+      assert.equals('file"name.lua', filename)
+      vim.api.nvim_buf_delete(buf, { force = true })
+    end)
+
+    it('unquotes octal escapes in filenames', function()
+      local buf = create_status_buffer({
+        'Unstaged (1)',
+        'M  "\\303\\251le.lua"',
+      })
+      local filename = fugitive.get_file_at_line(buf, 2)
+      assert.equals('\195\169le.lua', filename)
+      vim.api.nvim_buf_delete(buf, { force = true })
+    end)
+
+    it('passes through unquoted filenames unchanged', function()
+      local buf = create_status_buffer({
+        'Unstaged (1)',
+        'M  normal.lua',
+      })
+      local filename = fugitive.get_file_at_line(buf, 2)
+      assert.equals('normal.lua', filename)
+      vim.api.nvim_buf_delete(buf, { force = true })
+    end)
+
+    it('unquotes renamed files with quotes', function()
       local buf = create_status_buffer({
         'Staged (1)',
-        'M  test.spec.lua',
+        'R100 "old name.lua" -> "new name.lua"',
       })
       local filename, _, _, old_filename = fugitive.get_file_at_line(buf, 2)
-      assert.equals('test.spec.lua', filename)
+      assert.equals('new name.lua', filename)
-      assert.is_nil(old_filename)
+      assert.equals('old name.lua', old_filename)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
-    it('handles hyphenated filenames', function()
-      local buf = create_status_buffer({
-        'Unstaged (1)',
-        'M  my-component-test.lua',
-      })
-      local filename, section = fugitive.get_file_at_line(buf, 2)
-      assert.equals('my-component-test.lua', filename)
-      assert.equals('unstaged', section)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
-    it('handles underscores and numbers', function()
-      local buf = create_status_buffer({
-        'Staged (1)',
-        'A  test_file_123.lua',
-      })
-      local filename = fugitive.get_file_at_line(buf, 2)
-      assert.equals('test_file_123.lua', filename)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
-    it('handles dotfiles', function()
-      local buf = create_status_buffer({
-        'Unstaged (1)',
-        'M  .gitignore',
-      })
-      local filename = fugitive.get_file_at_line(buf, 2)
-      assert.equals('.gitignore', filename)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
-    it('handles renamed with complex names', function()
-      local buf = create_status_buffer({
-        'Staged (1)',
-        'R  src/old-file.spec.lua -> src/new-file.spec.lua',
-      })
-      local filename, _, _, old_filename = fugitive.get_file_at_line(buf, 2)
-      assert.equals('src/new-file.spec.lua', filename)
-      assert.equals('src/old-file.spec.lua', old_filename)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
-    it('handles deeply nested paths', function()
-      local buf = create_status_buffer({
-        'Unstaged (1)',
-        'M  lua/diffs/ui/components/diff-view.lua',
-      })
-      local filename = fugitive.get_file_at_line(buf, 2)
-      assert.equals('lua/diffs/ui/components/diff-view.lua', filename)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
-    it('parses untracked file', function()
-      local buf = create_status_buffer({
-        'Untracked (1)',
-        '?  untracked.lua',
-      })
-      local filename, section = fugitive.get_file_at_line(buf, 2)
-      assert.equals('untracked.lua', filename)
-      assert.equals('untracked', section)
       vim.api.nvim_buf_delete(buf, { force = true })
     end)
 
@@ -321,30 +254,6 @@ describe('fugitive', function()
       vim.api.nvim_buf_delete(buf, { force = true })
     end)
 
-    it('detects section header for Unstaged', function()
-      local buf = create_status_buffer({
-        'Unstaged (3)',
-        'M  file1.lua',
-      })
-      local filename, section, is_header = fugitive.get_file_at_line(buf, 1)
-      assert.is_nil(filename)
-      assert.equals('unstaged', section)
-      assert.is_true(is_header)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
-    it('detects section header for Untracked', function()
-      local buf = create_status_buffer({
-        'Untracked (1)',
-        '?  newfile.lua',
-      })
-      local filename, section, is_header = fugitive.get_file_at_line(buf, 1)
-      assert.is_nil(filename)
-      assert.equals('untracked', section)
-      assert.is_true(is_header)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
     it('returns is_header=false for file lines', function()
       local buf = create_status_buffer({
         'Staged (1)',
@@ -406,22 +315,6 @@ describe('fugitive', function()
       vim.api.nvim_buf_delete(buf, { force = true })
     end)
 
-    it('returns hunk header and offset for - line', function()
-      local buf = create_status_buffer({
-        'Unstaged (1)',
-        'M  file.lua',
-        '@@ -1,3 +1,3 @@',
-        ' local M = {}',
-        '-local old = false',
-        ' return M',
-      })
-      local pos = fugitive.get_hunk_position(buf, 5)
-      assert.is_not_nil(pos)
-      assert.equals('@@ -1,3 +1,3 @@', pos.hunk_header)
-      assert.equals(2, pos.offset)
-      vim.api.nvim_buf_delete(buf, { force = true })
-    end)
-
     it('returns hunk header and offset for context line', function()
       local buf = create_status_buffer({
         'Unstaged (1)',

spec/highlight_spec.lua

@@ -51,6 +51,12 @@ describe('highlight', function()
             algorithm = 'default',
             max_lines = 500,
           },
+          priorities = {
+            clear = 198,
+            syntax = 199,
+            line_bg = 200,
+            char_bg = 201,
+          },
         },
       }
       if overrides then
@@ -64,27 +70,6 @@ describe('highlight', function()
       return opts
     end
 
-    it('applies extmarks for lua code', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { ' local x = 1', '+local y = 2' },
-      }
-
-      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
-
-      local extmarks = get_extmarks(bufnr)
-      assert.is_true(#extmarks > 0)
-      delete_buffer(bufnr)
-    end)
-
     it('applies DiffsClear extmarks to clear diff colors', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
@@ -190,36 +175,6 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('highlights header context when enabled', function()
-      local bufnr = create_buffer({
-        '@@ -10,3 +10,4 @@ function hello()',
-        ' local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        header_context = 'function hello()',
-        header_context_col = 18,
-        lines = { ' local x = 1', '+local y = 2' },
-      }
-
-      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
-
-      local extmarks = get_extmarks(bufnr)
-      local has_header_extmark = false
-      for _, mark in ipairs(extmarks) do
-        if mark[2] == 0 then
-          has_header_extmark = true
-          break
-        end
-      end
-      assert.is_true(has_header_extmark)
-      delete_buffer(bufnr)
-    end)
-
     it('highlights function keyword in header context', function()
       local bufnr = create_buffer({
         '@@ -5,3 +5,4 @@ function M.setup()',
@@ -280,44 +235,6 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('handles empty hunk lines', function()
-      local bufnr = create_buffer({
-        '@@ -1,0 +1,0 @@',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = {},
-      }
-
-      assert.has_no.errors(function()
-        highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
-      end)
-      delete_buffer(bufnr)
-    end)
-
-    it('handles code that is just whitespace', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' ',
-        '+  ',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { ' ', '+  ' },
-      }
-
-      assert.has_no.errors(function()
-        highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
-      end)
-      delete_buffer(bufnr)
-    end)
-
     it('applies overlay extmarks when hide_prefix enabled', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
@@ -345,33 +262,6 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('does not apply overlay extmarks when hide_prefix disabled', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { ' local x = 1', '+local y = 2' },
-      }
-
-      highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ hide_prefix = false }))
-
-      local extmarks = get_extmarks(bufnr)
-      local overlay_count = 0
-      for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].virt_text_pos == 'overlay' then
-          overlay_count = overlay_count + 1
-        end
-      end
-      assert.are.equal(0, overlay_count)
-      delete_buffer(bufnr)
-    end)
-
     it('applies DiffAdd background to + lines when background enabled', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
@@ -438,39 +328,6 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('does not apply background when background disabled', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { ' local x = 1', '+local y = 2' },
-      }
-
-      highlight.highlight_hunk(
-        bufnr,
-        ns,
-        hunk,
-        default_opts({ highlights = { background = false } })
-      )
-
-      local extmarks = get_extmarks(bufnr)
-      local has_line_hl = false
-      for _, mark in ipairs(extmarks) do
-        if mark[4] and (mark[4].hl_group == 'DiffsAdd' or mark[4].hl_group == 'DiffsDelete') then
-          has_line_hl = true
-          break
-        end
-      end
-      assert.is_false(has_line_hl)
-      delete_buffer(bufnr)
-    end)
-
     it('applies number_hl_group when gutter enabled', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
@@ -504,72 +361,6 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('does not apply number_hl_group when gutter disabled', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { ' local x = 1', '+local y = 2' },
-      }
-
-      highlight.highlight_hunk(
-        bufnr,
-        ns,
-        hunk,
-        default_opts({ highlights = { background = true, gutter = false } })
-      )
-
-      local extmarks = get_extmarks(bufnr)
-      local has_number_hl = false
-      for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].number_hl_group then
-          has_number_hl = true
-          break
-        end
-      end
-      assert.is_false(has_number_hl)
-      delete_buffer(bufnr)
-    end)
-
-    it('skips treesitter highlights when treesitter disabled', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { ' local x = 1', '+local y = 2' },
-      }
-
-      highlight.highlight_hunk(
-        bufnr,
-        ns,
-        hunk,
-        default_opts({ highlights = { treesitter = { enabled = false }, background = true } })
-      )
-
-      local extmarks = get_extmarks(bufnr)
-      local has_ts_highlight = false
-      for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].hl_group and mark[4].hl_group:match('^@') then
-          has_ts_highlight = true
-          break
-        end
-      end
-      assert.is_false(has_ts_highlight)
-      delete_buffer(bufnr)
-    end)
-
     it('still applies background when treesitter disabled', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
@@ -654,40 +445,6 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('skips vim fallback when vim.enabled is false', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        ft = 'abap',
-        lang = nil,
-        start_line = 1,
-        lines = { ' local x = 1', '+local y = 2' },
-      }
-
-      highlight.highlight_hunk(
-        bufnr,
-        ns,
-        hunk,
-        default_opts({ highlights = { vim = { enabled = false } } })
-      )
-
-      local extmarks = get_extmarks(bufnr)
-      local has_syntax_hl = false
-      for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].hl_group and mark[4].hl_group ~= 'DiffsClear' then
-          has_syntax_hl = true
-          break
-        end
-      end
-      assert.is_false(has_syntax_hl)
-      delete_buffer(bufnr)
-    end)
-
     it('respects vim.max_lines', function()
       local lines = { '@@ -1,100 +1,101 @@' }
       local hunk_lines = {}
@@ -900,92 +657,6 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('line bg priority > DiffsClear priority', function()
-      local bufnr = create_buffer({
-        '@@ -1,2 +1,1 @@',
-        '-local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { '-local x = 1', '+local y = 2' },
-      }
-
-      highlight.highlight_hunk(
-        bufnr,
-        ns,
-        hunk,
-        default_opts({ highlights = { background = true } })
-      )
-
-      local extmarks = get_extmarks(bufnr)
-      local clear_priority = nil
-      local line_bg_priority = nil
-      for _, mark in ipairs(extmarks) do
-        local d = mark[4]
-        if d and d.hl_group == 'DiffsClear' then
-          clear_priority = d.priority
-        end
-        if d and (d.hl_group == 'DiffsAdd' or d.hl_group == 'DiffsDelete') then
-          line_bg_priority = d.priority
-        end
-      end
-      assert.is_not_nil(clear_priority)
-      assert.is_not_nil(line_bg_priority)
-      assert.is_true(line_bg_priority > clear_priority)
-      delete_buffer(bufnr)
-    end)
-
-    it('char-level extmarks have higher priority than line bg', function()
-      vim.api.nvim_set_hl(0, 'DiffsAddText', { bg = 0x00FF00 })
-      vim.api.nvim_set_hl(0, 'DiffsDeleteText', { bg = 0xFF0000 })
-
-      local bufnr = create_buffer({
-        '@@ -1,2 +1,2 @@',
-        '-local x = 1',
-        '+local x = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { '-local x = 1', '+local x = 2' },
-      }
-
-      highlight.highlight_hunk(
-        bufnr,
-        ns,
-        hunk,
-        default_opts({
-          highlights = {
-            background = true,
-            intra = { enabled = true, algorithm = 'default', max_lines = 500 },
-          },
-        })
-      )
-
-      local extmarks = get_extmarks(bufnr)
-      local line_bg_priority = nil
-      local char_bg_priority = nil
-      for _, mark in ipairs(extmarks) do
-        local d = mark[4]
-        if d and (d.hl_group == 'DiffsAdd' or d.hl_group == 'DiffsDelete') then
-          line_bg_priority = d.priority
-        end
-        if d and (d.hl_group == 'DiffsAddText' or d.hl_group == 'DiffsDeleteText') then
-          char_bg_priority = d.priority
-        end
-      end
-      assert.is_not_nil(line_bg_priority)
-      assert.is_not_nil(char_bg_priority)
-      assert.is_true(char_bg_priority > line_bg_priority)
-      delete_buffer(bufnr)
-    end)
-
     it('creates char-level extmarks for changed characters', function()
       vim.api.nvim_set_hl(0, 'DiffsAddText', { bg = 0x00FF00 })
       vim.api.nvim_set_hl(0, 'DiffsDeleteText', { bg = 0xFF0000 })
@@ -1029,38 +700,6 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('does not create char-level extmarks when intra disabled', function()
-      local bufnr = create_buffer({
-        '@@ -1,2 +1,2 @@',
-        '-local x = 1',
-        '+local x = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { '-local x = 1', '+local x = 2' },
-      }
-
-      highlight.highlight_hunk(
-        bufnr,
-        ns,
-        hunk,
-        default_opts({
-          highlights = { intra = { enabled = false, algorithm = 'default', max_lines = 500 } },
-        })
-      )
-
-      local extmarks = get_extmarks(bufnr)
-      for _, mark in ipairs(extmarks) do
-        local d = mark[4]
-        assert.is_not_equal('DiffsAddText', d and d.hl_group)
-        assert.is_not_equal('DiffsDeleteText', d and d.hl_group)
-      end
-      delete_buffer(bufnr)
-    end)
-
     it('does not create char-level extmarks for pure additions', function()
       vim.api.nvim_set_hl(0, 'DiffsAddText', { bg = 0x00FF00 })
 
@@ -1157,142 +796,6 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('context padding produces no extmarks on padding lines', function()
-      local repo_root = '/tmp/diffs-test-context'
-      vim.fn.mkdir(repo_root, 'p')
-
-      local f = io.open(repo_root .. '/test.lua', 'w')
-      f:write('local M = {}\n')
-      f:write('function M.hello()\n')
-      f:write('  return "hi"\n')
-      f:write('end\n')
-      f:write('return M\n')
-      f:close()
-
-      local bufnr = create_buffer({
-        '@@ -3,1 +3,2 @@',
-        ' return "hi"',
-        '+"bye"',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { '  return "hi"', '+"bye"' },
-        file_old_start = 3,
-        file_old_count = 1,
-        file_new_start = 3,
-        file_new_count = 2,
-        repo_root = repo_root,
-      }
-
-      highlight.highlight_hunk(
-        bufnr,
-        ns,
-        hunk,
-        default_opts({ highlights = { context = { enabled = true, lines = 25 } } })
-      )
-
-      local extmarks = get_extmarks(bufnr)
-      for _, mark in ipairs(extmarks) do
-        local row = mark[2]
-        assert.is_true(row >= 1 and row <= 2)
-      end
-
-      delete_buffer(bufnr)
-      os.remove(repo_root .. '/test.lua')
-      vim.fn.delete(repo_root, 'rf')
-    end)
-
-    it('context disabled matches behavior without padding', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { ' local x = 1', '+local y = 2' },
-        file_new_start = 1,
-        file_new_count = 2,
-        repo_root = '/nonexistent',
-      }
-
-      highlight.highlight_hunk(
-        bufnr,
-        ns,
-        hunk,
-        default_opts({ highlights = { context = { enabled = false, lines = 0 } } })
-      )
-
-      local extmarks = get_extmarks(bufnr)
-      assert.is_true(#extmarks > 0)
-      delete_buffer(bufnr)
-    end)
-
-    it('gracefully handles missing file for context padding', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { ' local x = 1', '+local y = 2' },
-        file_new_start = 1,
-        file_new_count = 2,
-        repo_root = '/nonexistent/path',
-      }
-
-      assert.has_no.errors(function()
-        highlight.highlight_hunk(
-          bufnr,
-          ns,
-          hunk,
-          default_opts({ highlights = { context = { enabled = true, lines = 25 } } })
-        )
-      end)
-
-      local extmarks = get_extmarks(bufnr)
-      assert.is_true(#extmarks > 0)
-      delete_buffer(bufnr)
-    end)
-
-    it('highlights treesitter injections', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' local x = 1',
-        '+vim.cmd([[ echo 1 ]])',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { ' local x = 1', '+vim.cmd([[ echo 1 ]])' },
-      }
-
-      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
-
-      local extmarks = get_extmarks(bufnr)
-      local has_vim_capture = false
-      for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].hl_group and mark[4].hl_group:match('^@.*%.vim$') then
-          has_vim_capture = true
-          break
-        end
-      end
-      assert.is_true(has_vim_capture)
-      delete_buffer(bufnr)
-    end)
-
     it('includes captures from both base and injected languages', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
@@ -1327,6 +830,114 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
+    it('applies DiffsAdd background to combined diff lines with + in prefix', function()
+      local bufnr = create_buffer({
+        '@@@ -1,3 -1,5 +1,9 @@@',
+        '  local M = {}',
+        '++<<<<<<< HEAD',
+        ' +  return 1',
+        '++=======',
+        '+   return 2',
+        '++>>>>>>> feature',
+      })
+
+      local hunk = {
+        filename = 'test.lua',
+        lang = 'lua',
+        start_line = 1,
+        prefix_width = 2,
+        lines = {
+          '  local M = {}',
+          '++<<<<<<< HEAD',
+          ' +  return 1',
+          '++=======',
+          '+   return 2',
+          '++>>>>>>> feature',
+        },
+      }
+
+      highlight.highlight_hunk(
+        bufnr,
+        ns,
+        hunk,
+        default_opts({ highlights = { background = true } })
+      )
+
+      local extmarks = get_extmarks(bufnr)
+      local add_lines = {}
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].hl_group == 'DiffsAdd' then
+          add_lines[mark[2]] = true
+        end
+      end
+      assert.is_nil(add_lines[0])
+      assert.is_nil(add_lines[1])
+      assert.is_true(add_lines[2] ~= nil)
+      assert.is_true(add_lines[3] ~= nil)
+      assert.is_true(add_lines[4] ~= nil)
+      assert.is_true(add_lines[5] ~= nil)
+      assert.is_true(add_lines[6] ~= nil)
+      delete_buffer(bufnr)
+    end)
+
+    it('conceals 2-char prefix for combined diffs', function()
+      local bufnr = create_buffer({
+        '@@@ -1,2 -1,2 +1,3 @@@',
+        '  local M = {}',
+        '++<<<<<<< HEAD',
+      })
+
+      local hunk = {
+        filename = 'test.lua',
+        lang = 'lua',
+        start_line = 1,
+        prefix_width = 2,
+        lines = { '  local M = {}', '++<<<<<<< HEAD' },
+      }
+
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ hide_prefix = true }))
+
+      local extmarks = get_extmarks(bufnr)
+      local overlay_count = 0
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].virt_text_pos == 'overlay' then
+          overlay_count = overlay_count + 1
+          assert.are.equal('  ', mark[4].virt_text[1][1])
+        end
+      end
+      assert.are.equal(2, overlay_count)
+      delete_buffer(bufnr)
+    end)
+
+    it('produces treesitter captures on combined diff content lines', function()
+      local bufnr = create_buffer({
+        '@@@ -1,2 -1,2 +1,3 @@@',
+        '  local M = {}',
+        ' +local x = 1',
+      })
+
+      local hunk = {
+        filename = 'test.lua',
+        lang = 'lua',
+        start_line = 1,
+        prefix_width = 2,
+        lines = { '  local M = {}', ' +local x = 1' },
+      }
+
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
+
+      local extmarks = get_extmarks(bufnr)
+      local has_ts = false
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].hl_group and mark[4].hl_group:match('^@.*%.lua$') then
+          has_ts = true
+          break
+        end
+      end
+      assert.is_true(has_ts)
+      delete_buffer(bufnr)
+    end)
+
     it('filters @spell and @nospell captures from injections', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
@@ -1386,6 +997,7 @@ describe('highlight', function()
           context = { enabled = false, lines = 0 },
           treesitter = { enabled = true, max_lines = 500 },
           vim = { enabled = false, max_lines = 200 },
+          priorities = { clear = 198, syntax = 199, line_bg = 200, char_bg = 201 },
         },
       }
     end
@@ -1468,47 +1080,6 @@ describe('highlight', function()
       assert.are.equal(0, header_extmarks)
       delete_buffer(bufnr)
     end)
-
-    it('does not apply header highlights when treesitter disabled', function()
-      local bufnr = create_buffer({
-        'diff --git a/parser.lua b/parser.lua',
-        'index 3e8afa0..018159c 100644',
-        '--- a/parser.lua',
-        '+++ b/parser.lua',
-        '@@ -1,2 +1,3 @@',
-        ' local M = {}',
-        '+local x = 1',
-      })
-
-      local hunk = {
-        filename = 'parser.lua',
-        lang = 'lua',
-        start_line = 5,
-        lines = { ' local M = {}', '+local x = 1' },
-        header_start_line = 1,
-        header_lines = {
-          'diff --git a/parser.lua b/parser.lua',
-          'index 3e8afa0..018159c 100644',
-          '--- a/parser.lua',
-          '+++ b/parser.lua',
-        },
-      }
-
-      local opts = default_opts()
-      opts.highlights.treesitter.enabled = false
-
-      highlight.highlight_hunk(bufnr, ns, hunk, opts)
-
-      local extmarks = get_extmarks(bufnr)
-      local header_extmarks = 0
-      for _, mark in ipairs(extmarks) do
-        if mark[2] < 4 and mark[4] and mark[4].hl_group and mark[4].hl_group:match('^@') then
-          header_extmarks = header_extmarks + 1
-        end
-      end
-      assert.are.equal(0, header_extmarks)
-      delete_buffer(bufnr)
-    end)
   end)
 
   describe('extmark priority', function()
@@ -1543,40 +1114,11 @@ describe('highlight', function()
           context = { enabled = false, lines = 0 },
           treesitter = { enabled = true, max_lines = 500 },
           vim = { enabled = false, max_lines = 200 },
+          priorities = { clear = 198, syntax = 199, line_bg = 200, char_bg = 201 },
         },
       }
     end
 
-    it('uses priority 199 for code languages', function()
-      local bufnr = create_buffer({
-        '@@ -1,1 +1,2 @@',
-        ' local x = 1',
-        '+local y = 2',
-      })
-
-      local hunk = {
-        filename = 'test.lua',
-        lang = 'lua',
-        start_line = 1,
-        lines = { ' local x = 1', '+local y = 2' },
-      }
-
-      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
-
-      local extmarks = get_extmarks(bufnr)
-      local has_priority_199 = false
-      for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].hl_group and mark[4].hl_group:match('^@.*%.lua$') then
-          if mark[4].priority == 199 then
-            has_priority_199 = true
-            break
-          end
-        end
-      end
-      assert.is_true(has_priority_199)
-      delete_buffer(bufnr)
-    end)
-
     it('uses treesitter priority for diff language', function()
       local bufnr = create_buffer({
         'diff --git a/test.lua b/test.lua',

spec/merge_spec.lua

@@ -0,0 +1,815 @@
+local helpers = require('spec.helpers')
+local merge = require('diffs.merge')
+
+local function default_config(overrides)
+  local cfg = {
+    enabled = true,
+    disable_diagnostics = false,
+    show_virtual_text = true,
+    show_actions = false,
+    keymaps = {
+      ours = 'doo',
+      theirs = 'dot',
+      both = 'dob',
+      none = 'don',
+      next = ']x',
+      prev = '[x',
+    },
+  }
+  if overrides then
+    cfg = vim.tbl_deep_extend('force', cfg, overrides)
+  end
+  return cfg
+end
+
+local function create_diff_buffer(lines, working_path)
+  local bufnr = helpers.create_buffer(lines)
+  if working_path then
+    vim.api.nvim_buf_set_var(bufnr, 'diffs_working_path', working_path)
+  end
+  return bufnr
+end
+
+local function create_working_buffer(lines, name)
+  local bufnr = vim.api.nvim_create_buf(true, false)
+  vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, lines)
+  if name then
+    vim.api.nvim_buf_set_name(bufnr, name)
+  end
+  return bufnr
+end
+
+describe('merge', function()
+  describe('parse_hunks', function()
+    it('parses a single hunk', function()
+      local bufnr = helpers.create_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,3 +1,3 @@',
+        ' local M = {}',
+        '-local x = 1',
+        '+local x = 2',
+        ' return M',
+      })
+
+      local hunks = merge.parse_hunks(bufnr)
+      assert.are.equal(1, #hunks)
+      assert.are.equal(3, hunks[1].start_line)
+      assert.are.equal(7, hunks[1].end_line)
+      assert.are.same({ 'local x = 1' }, hunks[1].del_lines)
+      assert.are.same({ 'local x = 2' }, hunks[1].add_lines)
+
+      helpers.delete_buffer(bufnr)
+    end)
+
+    it('parses multiple hunks', function()
+      local bufnr = helpers.create_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,3 +1,3 @@',
+        ' local M = {}',
+        '-local x = 1',
+        '+local x = 2',
+        ' return M',
+        '@@ -10,3 +10,3 @@',
+        ' function M.foo()',
+        '-  return 1',
+        '+  return 2',
+        ' end',
+      })
+
+      local hunks = merge.parse_hunks(bufnr)
+      assert.are.equal(2, #hunks)
+      assert.are.equal(3, hunks[1].start_line)
+      assert.are.equal(8, hunks[2].start_line)
+
+      helpers.delete_buffer(bufnr)
+    end)
+
+    it('parses add-only hunk', function()
+      local bufnr = helpers.create_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,2 +1,3 @@',
+        ' local M = {}',
+        '+local new = true',
+        ' return M',
+      })
+
+      local hunks = merge.parse_hunks(bufnr)
+      assert.are.equal(1, #hunks)
+      assert.are.same({}, hunks[1].del_lines)
+      assert.are.same({ 'local new = true' }, hunks[1].add_lines)
+
+      helpers.delete_buffer(bufnr)
+    end)
+
+    it('parses delete-only hunk', function()
+      local bufnr = helpers.create_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,3 +1,2 @@',
+        ' local M = {}',
+        '-local old = false',
+        ' return M',
+      })
+
+      local hunks = merge.parse_hunks(bufnr)
+      assert.are.equal(1, #hunks)
+      assert.are.same({ 'local old = false' }, hunks[1].del_lines)
+      assert.are.same({}, hunks[1].add_lines)
+
+      helpers.delete_buffer(bufnr)
+    end)
+
+    it('returns empty for buffer with no hunks', function()
+      local bufnr = helpers.create_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+      })
+
+      local hunks = merge.parse_hunks(bufnr)
+      assert.are.equal(0, #hunks)
+
+      helpers.delete_buffer(bufnr)
+    end)
+  end)
+
+  describe('match_hunk_to_conflict', function()
+    it('matches hunk to conflict region', function()
+      local working_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      }, '/tmp/diffs_test_match.lua')
+
+      local hunk = {
+        index = 1,
+        start_line = 3,
+        end_line = 7,
+        del_lines = { 'local x = 1' },
+        add_lines = { 'local x = 2' },
+      }
+
+      local region = merge.match_hunk_to_conflict(hunk, working_bufnr)
+      assert.is_not_nil(region)
+      assert.are.equal(0, region.marker_ours)
+
+      helpers.delete_buffer(working_bufnr)
+    end)
+
+    it('returns nil for auto-merged content', function()
+      local working_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      }, '/tmp/diffs_test_auto.lua')
+
+      local hunk = {
+        index = 1,
+        start_line = 3,
+        end_line = 7,
+        del_lines = { 'local y = 3' },
+        add_lines = { 'local y = 4' },
+      }
+
+      local region = merge.match_hunk_to_conflict(hunk, working_bufnr)
+      assert.is_nil(region)
+
+      helpers.delete_buffer(working_bufnr)
+    end)
+
+    it('matches with empty ours section', function()
+      local working_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      }, '/tmp/diffs_test_empty_ours.lua')
+
+      local hunk = {
+        index = 1,
+        start_line = 3,
+        end_line = 5,
+        del_lines = {},
+        add_lines = { 'local x = 2' },
+      }
+
+      local region = merge.match_hunk_to_conflict(hunk, working_bufnr)
+      assert.is_not_nil(region)
+
+      helpers.delete_buffer(working_bufnr)
+    end)
+
+    it('matches correct region among multiple conflicts', function()
+      local working_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local a = 1',
+        '=======',
+        'local a = 2',
+        '>>>>>>> feature',
+        'middle',
+        '<<<<<<< HEAD',
+        'local b = 3',
+        '=======',
+        'local b = 4',
+        '>>>>>>> feature',
+      }, '/tmp/diffs_test_multi.lua')
+
+      local hunk = {
+        index = 2,
+        start_line = 8,
+        end_line = 12,
+        del_lines = { 'local b = 3' },
+        add_lines = { 'local b = 4' },
+      }
+
+      local region = merge.match_hunk_to_conflict(hunk, working_bufnr)
+      assert.is_not_nil(region)
+      assert.are.equal(6, region.marker_ours)
+
+      helpers.delete_buffer(working_bufnr)
+    end)
+
+    it('matches with diff3 format', function()
+      local working_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '||||||| base',
+        'local x = 0',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      }, '/tmp/diffs_test_diff3.lua')
+
+      local hunk = {
+        index = 1,
+        start_line = 3,
+        end_line = 7,
+        del_lines = { 'local x = 1' },
+        add_lines = { 'local x = 2' },
+      }
+
+      local region = merge.match_hunk_to_conflict(hunk, working_bufnr)
+      assert.is_not_nil(region)
+      assert.are.equal(2, region.marker_base)
+
+      helpers.delete_buffer(working_bufnr)
+    end)
+  end)
+
+  describe('resolution', function()
+    local diff_bufnr, working_bufnr
+
+    local function setup_buffers()
+      local working_path = '/tmp/diffs_test_resolve.lua'
+      working_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      }, working_path)
+
+      diff_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local x = 1',
+        '+local x = 2',
+      }, working_path)
+      vim.api.nvim_set_current_buf(diff_bufnr)
+    end
+
+    local function cleanup()
+      helpers.delete_buffer(diff_bufnr)
+      helpers.delete_buffer(working_bufnr)
+    end
+
+    it('resolve_ours keeps ours content in working file', function()
+      setup_buffers()
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      merge.resolve_ours(diff_bufnr, default_config())
+
+      local lines = vim.api.nvim_buf_get_lines(working_bufnr, 0, -1, false)
+      assert.are.equal(1, #lines)
+      assert.are.equal('local x = 1', lines[1])
+
+      cleanup()
+    end)
+
+    it('resolve_theirs keeps theirs content in working file', function()
+      setup_buffers()
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      merge.resolve_theirs(diff_bufnr, default_config())
+
+      local lines = vim.api.nvim_buf_get_lines(working_bufnr, 0, -1, false)
+      assert.are.equal(1, #lines)
+      assert.are.equal('local x = 2', lines[1])
+
+      cleanup()
+    end)
+
+    it('resolve_both keeps ours then theirs in working file', function()
+      setup_buffers()
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      merge.resolve_both(diff_bufnr, default_config())
+
+      local lines = vim.api.nvim_buf_get_lines(working_bufnr, 0, -1, false)
+      assert.are.equal(2, #lines)
+      assert.are.equal('local x = 1', lines[1])
+      assert.are.equal('local x = 2', lines[2])
+
+      cleanup()
+    end)
+
+    it('resolve_none removes entire block from working file', function()
+      setup_buffers()
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      merge.resolve_none(diff_bufnr, default_config())
+
+      local lines = vim.api.nvim_buf_get_lines(working_bufnr, 0, -1, false)
+      assert.are.equal(1, #lines)
+      assert.are.equal('', lines[1])
+
+      cleanup()
+    end)
+
+    it('tracks resolved hunks', function()
+      setup_buffers()
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      assert.is_false(merge.is_resolved(diff_bufnr, 1))
+      merge.resolve_ours(diff_bufnr, default_config())
+      assert.is_true(merge.is_resolved(diff_bufnr, 1))
+
+      cleanup()
+    end)
+
+    it('adds virtual text for resolved hunks', function()
+      setup_buffers()
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      merge.resolve_ours(diff_bufnr, default_config())
+
+      local extmarks =
+        vim.api.nvim_buf_get_extmarks(diff_bufnr, merge.get_namespace(), 0, -1, { details = true })
+      local has_resolved_text = false
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].virt_text then
+          for _, chunk in ipairs(mark[4].virt_text) do
+            if chunk[1]:match('resolved') then
+              has_resolved_text = true
+            end
+          end
+        end
+      end
+      assert.is_true(has_resolved_text)
+
+      cleanup()
+    end)
+
+    it('notifies when hunk is already resolved', function()
+      setup_buffers()
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      merge.resolve_ours(diff_bufnr, default_config())
+
+      local notified = false
+      local orig_notify = vim.notify
+      vim.notify = function(msg)
+        if msg:match('already resolved') then
+          notified = true
+        end
+      end
+
+      merge.resolve_ours(diff_bufnr, default_config())
+      vim.notify = orig_notify
+
+      assert.is_true(notified)
+
+      cleanup()
+    end)
+
+    it('notifies when hunk does not match a conflict', function()
+      local working_path = '/tmp/diffs_test_no_conflict.lua'
+      local w_bufnr = create_working_buffer({
+        'local y = 1',
+      }, working_path)
+
+      local d_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local x = 1',
+        '+local x = 2',
+      }, working_path)
+      vim.api.nvim_set_current_buf(d_bufnr)
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      local notified = false
+      local orig_notify = vim.notify
+      vim.notify = function(msg)
+        if msg:match('does not correspond') then
+          notified = true
+        end
+      end
+
+      merge.resolve_ours(d_bufnr, default_config())
+      vim.notify = orig_notify
+
+      assert.is_true(notified)
+
+      helpers.delete_buffer(d_bufnr)
+      helpers.delete_buffer(w_bufnr)
+    end)
+  end)
+
+  describe('navigation', function()
+    it('goto_next jumps to next conflict hunk', function()
+      local working_path = '/tmp/diffs_test_nav.lua'
+      local w_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local a = 1',
+        '=======',
+        'local a = 2',
+        '>>>>>>> feature',
+        'middle',
+        '<<<<<<< HEAD',
+        'local b = 3',
+        '=======',
+        'local b = 4',
+        '>>>>>>> feature',
+      }, working_path)
+
+      local d_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local a = 1',
+        '+local a = 2',
+        '@@ -5,1 +5,1 @@',
+        '-local b = 3',
+        '+local b = 4',
+      }, working_path)
+      vim.api.nvim_set_current_buf(d_bufnr)
+      vim.api.nvim_win_set_cursor(0, { 1, 0 })
+
+      merge.goto_next(d_bufnr)
+      assert.are.equal(4, vim.api.nvim_win_get_cursor(0)[1])
+
+      merge.goto_next(d_bufnr)
+      assert.are.equal(7, vim.api.nvim_win_get_cursor(0)[1])
+
+      helpers.delete_buffer(d_bufnr)
+      helpers.delete_buffer(w_bufnr)
+    end)
+
+    it('goto_next wraps around', function()
+      local working_path = '/tmp/diffs_test_wrap.lua'
+      local w_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      }, working_path)
+
+      local d_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local x = 1',
+        '+local x = 2',
+      }, working_path)
+      vim.api.nvim_set_current_buf(d_bufnr)
+      vim.api.nvim_win_set_cursor(0, { 6, 0 })
+
+      merge.goto_next(d_bufnr)
+      assert.are.equal(4, vim.api.nvim_win_get_cursor(0)[1])
+
+      helpers.delete_buffer(d_bufnr)
+      helpers.delete_buffer(w_bufnr)
+    end)
+
+    it('goto_next notifies on wrap-around', function()
+      local working_path = '/tmp/diffs_test_wrap_notify.lua'
+      local w_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      }, working_path)
+
+      local d_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local x = 1',
+        '+local x = 2',
+      }, working_path)
+      vim.api.nvim_set_current_buf(d_bufnr)
+      vim.api.nvim_win_set_cursor(0, { 6, 0 })
+
+      local notified = false
+      local orig_notify = vim.notify
+      vim.notify = function(msg)
+        if msg:match('wrapped to first hunk') then
+          notified = true
+        end
+      end
+
+      merge.goto_next(d_bufnr)
+      vim.notify = orig_notify
+
+      assert.is_true(notified)
+
+      helpers.delete_buffer(d_bufnr)
+      helpers.delete_buffer(w_bufnr)
+    end)
+
+    it('goto_prev jumps to previous conflict hunk', function()
+      local working_path = '/tmp/diffs_test_prev.lua'
+      local w_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local a = 1',
+        '=======',
+        'local a = 2',
+        '>>>>>>> feature',
+        'middle',
+        '<<<<<<< HEAD',
+        'local b = 3',
+        '=======',
+        'local b = 4',
+        '>>>>>>> feature',
+      }, working_path)
+
+      local d_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local a = 1',
+        '+local a = 2',
+        '@@ -5,1 +5,1 @@',
+        '-local b = 3',
+        '+local b = 4',
+      }, working_path)
+      vim.api.nvim_set_current_buf(d_bufnr)
+      vim.api.nvim_win_set_cursor(0, { 9, 0 })
+
+      merge.goto_prev(d_bufnr)
+      assert.are.equal(7, vim.api.nvim_win_get_cursor(0)[1])
+
+      merge.goto_prev(d_bufnr)
+      assert.are.equal(4, vim.api.nvim_win_get_cursor(0)[1])
+
+      helpers.delete_buffer(d_bufnr)
+      helpers.delete_buffer(w_bufnr)
+    end)
+
+    it('goto_prev wraps around', function()
+      local working_path = '/tmp/diffs_test_prev_wrap.lua'
+      local w_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      }, working_path)
+
+      local d_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local x = 1',
+        '+local x = 2',
+      }, working_path)
+      vim.api.nvim_set_current_buf(d_bufnr)
+      vim.api.nvim_win_set_cursor(0, { 1, 0 })
+
+      merge.goto_prev(d_bufnr)
+      assert.are.equal(4, vim.api.nvim_win_get_cursor(0)[1])
+
+      helpers.delete_buffer(d_bufnr)
+      helpers.delete_buffer(w_bufnr)
+    end)
+
+    it('goto_prev notifies on wrap-around', function()
+      local working_path = '/tmp/diffs_test_prev_wrap_notify.lua'
+      local w_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      }, working_path)
+
+      local d_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local x = 1',
+        '+local x = 2',
+      }, working_path)
+      vim.api.nvim_set_current_buf(d_bufnr)
+      vim.api.nvim_win_set_cursor(0, { 1, 0 })
+
+      local notified = false
+      local orig_notify = vim.notify
+      vim.notify = function(msg)
+        if msg:match('wrapped to last hunk') then
+          notified = true
+        end
+      end
+
+      merge.goto_prev(d_bufnr)
+      vim.notify = orig_notify
+
+      assert.is_true(notified)
+
+      helpers.delete_buffer(d_bufnr)
+      helpers.delete_buffer(w_bufnr)
+    end)
+
+    it('skips resolved hunks', function()
+      local working_path = '/tmp/diffs_test_skip_resolved.lua'
+      local w_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local a = 1',
+        '=======',
+        'local a = 2',
+        '>>>>>>> feature',
+        'middle',
+        '<<<<<<< HEAD',
+        'local b = 3',
+        '=======',
+        'local b = 4',
+        '>>>>>>> feature',
+      }, working_path)
+
+      local d_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local a = 1',
+        '+local a = 2',
+        '@@ -5,1 +5,1 @@',
+        '-local b = 3',
+        '+local b = 4',
+      }, working_path)
+      vim.api.nvim_set_current_buf(d_bufnr)
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      merge.resolve_ours(d_bufnr, default_config())
+
+      vim.api.nvim_win_set_cursor(0, { 1, 0 })
+      merge.goto_next(d_bufnr)
+      assert.are.equal(7, vim.api.nvim_win_get_cursor(0)[1])
+
+      helpers.delete_buffer(d_bufnr)
+      helpers.delete_buffer(w_bufnr)
+    end)
+  end)
+
+  describe('hunk hints', function()
+    it('adds keymap hints on hunk header lines', function()
+      local d_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local x = 1',
+        '+local x = 2',
+      })
+
+      merge.setup_keymaps(d_bufnr, default_config())
+
+      local extmarks =
+        vim.api.nvim_buf_get_extmarks(d_bufnr, merge.get_namespace(), 0, -1, { details = true })
+      local hint_marks = {}
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].virt_text then
+          local text = ''
+          for _, chunk in ipairs(mark[4].virt_text) do
+            text = text .. chunk[1]
+          end
+          table.insert(hint_marks, { line = mark[2], text = text })
+        end
+      end
+      assert.are.equal(1, #hint_marks)
+      assert.are.equal(3, hint_marks[1].line)
+      assert.is_truthy(hint_marks[1].text:find('doo'))
+      assert.is_truthy(hint_marks[1].text:find('dot'))
+
+      helpers.delete_buffer(d_bufnr)
+    end)
+  end)
+
+  describe('setup_keymaps', function()
+    it('clears resolved state on re-init', function()
+      local working_path = '/tmp/diffs_test_reinit.lua'
+      local w_bufnr = create_working_buffer({
+        '<<<<<<< HEAD',
+        'local x = 1',
+        '=======',
+        'local x = 2',
+        '>>>>>>> feature',
+      }, working_path)
+
+      local d_bufnr = create_diff_buffer({
+        'diff --git a/file.lua b/file.lua',
+        '--- a/file.lua',
+        '+++ b/file.lua',
+        '@@ -1,1 +1,1 @@',
+        '-local x = 1',
+        '+local x = 2',
+      }, working_path)
+      vim.api.nvim_set_current_buf(d_bufnr)
+      vim.api.nvim_win_set_cursor(0, { 5, 0 })
+
+      local cfg = default_config()
+      merge.resolve_ours(d_bufnr, cfg)
+      assert.is_true(merge.is_resolved(d_bufnr, 1))
+
+      local extmarks =
+        vim.api.nvim_buf_get_extmarks(d_bufnr, merge.get_namespace(), 0, -1, { details = true })
+      assert.is_true(#extmarks > 0)
+
+      merge.setup_keymaps(d_bufnr, cfg)
+
+      assert.is_false(merge.is_resolved(d_bufnr, 1))
+      extmarks =
+        vim.api.nvim_buf_get_extmarks(d_bufnr, merge.get_namespace(), 0, -1, { details = true })
+      local resolved_count = 0
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].virt_text then
+          for _, chunk in ipairs(mark[4].virt_text) do
+            if chunk[1]:match('resolved') then
+              resolved_count = resolved_count + 1
+            end
+          end
+        end
+      end
+      assert.are.equal(0, resolved_count)
+
+      helpers.delete_buffer(d_bufnr)
+      helpers.delete_buffer(w_bufnr)
+    end)
+  end)
+
+  describe('fugitive integration', function()
+    it('parse_file_line returns status for unmerged files', function()
+      local fugitive = require('diffs.fugitive')
+      local buf = vim.api.nvim_create_buf(false, true)
+      vim.api.nvim_buf_set_lines(buf, 0, -1, false, {
+        'Unstaged (1)',
+        'U  conflict.lua',
+      })
+      local filename, section, is_header, old_filename, status = fugitive.get_file_at_line(buf, 2)
+      assert.are.equal('conflict.lua', filename)
+      assert.are.equal('unstaged', section)
+      assert.is_false(is_header)
+      assert.is_nil(old_filename)
+      assert.are.equal('U', status)
+      vim.api.nvim_buf_delete(buf, { force = true })
+    end)
+
+    it('walkback from hunk line propagates status', function()
+      local fugitive = require('diffs.fugitive')
+      local buf = vim.api.nvim_create_buf(false, true)
+      vim.api.nvim_buf_set_lines(buf, 0, -1, false, {
+        'Unstaged (1)',
+        'U  conflict.lua',
+        '@@ -1,3 +1,4 @@',
+        ' local M = {}',
+        '+local new = true',
+      })
+      local _, _, _, _, status = fugitive.get_file_at_line(buf, 5)
+      assert.are.equal('U', status)
+      vim.api.nvim_buf_delete(buf, { force = true })
+    end)
+  end)
+end)

spec/parser_spec.lua

@@ -391,37 +391,6 @@ describe('parser', function()
       vim.fn.delete(repo_root, 'rf')
     end)
 
-    it('detects python from shebang without open buffer', function()
-      local repo_root = '/tmp/diffs-test-shebang-py'
-      vim.fn.mkdir(repo_root, 'p')
-
-      local file_path = repo_root .. '/deploy'
-      local f = io.open(file_path, 'w')
-      f:write('#!/usr/bin/env python3\n')
-      f:write('import sys\n')
-      f:write('print("hi")\n')
-      f:close()
-
-      local diff_buf = create_buffer({
-        'M deploy',
-        '@@ -1,2 +1,3 @@',
-        ' #!/usr/bin/env python3',
-        '+import sys',
-        ' print("hi")',
-      })
-      vim.api.nvim_buf_set_var(diff_buf, 'diffs_repo_root', repo_root)
-
-      local hunks = parser.parse_buffer(diff_buf)
-
-      assert.are.equal(1, #hunks)
-      assert.are.equal('deploy', hunks[1].filename)
-      assert.are.equal('python', hunks[1].ft)
-
-      delete_buffer(diff_buf)
-      os.remove(file_path)
-      vim.fn.delete(repo_root, 'rf')
-    end)
-
     it('extracts file line numbers from @@ header', function()
       local bufnr = create_buffer({
         'M lua/test.lua',
@@ -440,22 +409,6 @@ describe('parser', function()
       delete_buffer(bufnr)
     end)
 
-    it('extracts large line numbers from @@ header', function()
-      local bufnr = create_buffer({
-        'M lua/test.lua',
-        '@@ -100,20 +200,30 @@',
-        ' local M = {}',
-      })
-      local hunks = parser.parse_buffer(bufnr)
-
-      assert.are.equal(1, #hunks)
-      assert.are.equal(100, hunks[1].file_old_start)
-      assert.are.equal(20, hunks[1].file_old_count)
-      assert.are.equal(200, hunks[1].file_new_start)
-      assert.are.equal(30, hunks[1].file_new_count)
-      delete_buffer(bufnr)
-    end)
-
     it('defaults count to 1 when omitted in @@ header', function()
       local bufnr = create_buffer({
         'M lua/test.lua',
@@ -472,6 +425,81 @@ describe('parser', function()
       delete_buffer(bufnr)
     end)
 
+    it('recognizes U prefix for unmerged files', function()
+      local bufnr = create_buffer({
+        'U merge_me.lua',
+        '@@@ -1,3 -1,5 +1,9 @@@',
+        '  local M = {}',
+        '++<<<<<<< HEAD',
+        ' +  return 1',
+        '++=======',
+        '+   return 2',
+        '++>>>>>>> feature',
+      })
+      local hunks = parser.parse_buffer(bufnr)
+
+      assert.are.equal(1, #hunks)
+      assert.are.equal('merge_me.lua', hunks[1].filename)
+      assert.are.equal('lua', hunks[1].ft)
+      delete_buffer(bufnr)
+    end)
+
+    it('sets prefix_width from @@@ combined diff header', function()
+      local bufnr = create_buffer({
+        'U test.lua',
+        '@@@ -1,3 -1,5 +1,9 @@@',
+        '  local M = {}',
+        '++<<<<<<< HEAD',
+        ' +  return 1',
+      })
+      local hunks = parser.parse_buffer(bufnr)
+
+      assert.are.equal(1, #hunks)
+      assert.are.equal(2, hunks[1].prefix_width)
+      delete_buffer(bufnr)
+    end)
+
+    it('sets prefix_width 1 for standard @@ unified diff', function()
+      local bufnr = create_buffer({
+        'M test.lua',
+        '@@ -1,2 +1,3 @@',
+        ' local x = 1',
+        '+local y = 2',
+      })
+      local hunks = parser.parse_buffer(bufnr)
+
+      assert.are.equal(1, #hunks)
+      assert.are.equal(1, hunks[1].prefix_width)
+      delete_buffer(bufnr)
+    end)
+
+    it('extracts new range from combined diff header', function()
+      local bufnr = create_buffer({
+        'U test.lua',
+        '@@@ -1,3 -1,5 +1,9 @@@',
+        '  local M = {}',
+      })
+      local hunks = parser.parse_buffer(bufnr)
+
+      assert.are.equal(1, #hunks)
+      assert.are.equal(1, hunks[1].file_new_start)
+      assert.are.equal(9, hunks[1].file_new_count)
+      delete_buffer(bufnr)
+    end)
+
+    it('extracts header context from combined diff header', function()
+      local bufnr = create_buffer({
+        'U test.lua',
+        '@@@ -1,3 -1,5 +1,9 @@@ function M.greet()',
+        '  local M = {}',
+      })
+      local hunks = parser.parse_buffer(bufnr)
+
+      assert.are.equal(1, #hunks)
+      assert.are.equal('function M.greet()', hunks[1].header_context)
+      delete_buffer(bufnr)
+    end)
+
     it('stores repo_root on hunk when available', function()
       local bufnr = create_buffer({
         'M lua/test.lua',
@@ -487,18 +515,5 @@ describe('parser', function()
       assert.are.equal('/tmp/test-repo', hunks[1].repo_root)
       delete_buffer(bufnr)
     end)
-
-    it('repo_root is nil when not available', function()
-      local bufnr = create_buffer({
-        'M lua/test.lua',
-        '@@ -1,3 +1,4 @@',
-        ' local M = {}',
-      })
-      local hunks = parser.parse_buffer(bufnr)
-
-      assert.are.equal(1, #hunks)
-      assert.is_nil(hunks[1].repo_root)
-      delete_buffer(bufnr)
-    end)
   end)
 end)