From f3a72926d288aaf03c4e212e9f82a006fb300320 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Sun, 8 Feb 2026 16:28:18 -0500
Subject: [PATCH 1/4] doc: add plug mappings for merge conflict resolution

---
 doc/diffs.nvim.txt     | 35 +++++++++++++++++++++++++++++++++++
 lua/diffs/conflict.lua | 42 +++++++++++++-----------------------------
 plugin/diffs.lua       | 25 +++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 29 deletions(-)

diff --git a/doc/diffs.nvim.txt b/doc/diffs.nvim.txt
index 028d8ba..7663150 100644
--- a/doc/diffs.nvim.txt
+++ b/doc/diffs.nvim.txt
@@ -280,6 +280,41 @@ 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)')
+<
+
 Diff buffer mappings: ~
                                                               *diffs-q*
     q               Close the diff window. Available in all `diffs://`
diff --git a/lua/diffs/conflict.lua b/lua/diffs/conflict.lua
index f4468d2..9e62a15 100644
--- a/lua/diffs/conflict.lua
+++ b/lua/diffs/conflict.lua
@@ -348,35 +348,19 @@ end
 local function setup_keymaps(bufnr, config)
   local km = config.keymaps
 
-  if km.ours then
-    vim.keymap.set('n', km.ours, function()
-      M.resolve_ours(bufnr, config)
-    end, { buffer = bufnr })
-  end
-  if km.theirs then
-    vim.keymap.set('n', km.theirs, function()
-      M.resolve_theirs(bufnr, config)
-    end, { buffer = bufnr })
-  end
-  if km.both then
-    vim.keymap.set('n', km.both, function()
-      M.resolve_both(bufnr, config)
-    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 })
+  local maps = {
+    { km.ours, '<Plug>(diffs-conflict-ours)' },
+    { km.theirs, '<Plug>(diffs-conflict-theirs)' },
+    { km.both, '<Plug>(diffs-conflict-both)' },
+    { km.none, '<Plug>(diffs-conflict-none)' },
+    { km.next, '<Plug>(diffs-conflict-next)' },
+    { km.prev, '<Plug>(diffs-conflict-prev)' },
+  }
+
+  for _, map in ipairs(maps) do
+    if map[1] then
+      vim.keymap.set('n', map[1], map[2], { buffer = bufnr })
+    end
   end
 end
 
diff --git a/plugin/diffs.lua b/plugin/diffs.lua
index e4fc690..5d3c8b2 100644
--- a/plugin/diffs.lua
+++ b/plugin/diffs.lua
@@ -57,3 +57,28 @@ 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' })

From 49fc446aaeb2743c329bec31966d3de23b8c6cbf Mon Sep 17 00:00:00 2001
From: Barrett Ruth <62671086+barrettruth@users.noreply.github.com>
Date: Sun, 8 Feb 2026 16:29:39 -0500
Subject: [PATCH 2/4] doc: add plug mappings for merge conflict resolution
 (#98)

---
 doc/diffs.nvim.txt     | 35 +++++++++++++++++++++++++++++++++++
 lua/diffs/conflict.lua | 42 +++++++++++++-----------------------------
 plugin/diffs.lua       | 25 +++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 29 deletions(-)

diff --git a/doc/diffs.nvim.txt b/doc/diffs.nvim.txt
index 028d8ba..7663150 100644
--- a/doc/diffs.nvim.txt
+++ b/doc/diffs.nvim.txt
@@ -280,6 +280,41 @@ 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)')
+<
+
 Diff buffer mappings: ~
                                                               *diffs-q*
     q               Close the diff window. Available in all `diffs://`
diff --git a/lua/diffs/conflict.lua b/lua/diffs/conflict.lua
index f4468d2..9e62a15 100644
--- a/lua/diffs/conflict.lua
+++ b/lua/diffs/conflict.lua
@@ -348,35 +348,19 @@ end
 local function setup_keymaps(bufnr, config)
   local km = config.keymaps
 
-  if km.ours then
-    vim.keymap.set('n', km.ours, function()
-      M.resolve_ours(bufnr, config)
-    end, { buffer = bufnr })
-  end
-  if km.theirs then
-    vim.keymap.set('n', km.theirs, function()
-      M.resolve_theirs(bufnr, config)
-    end, { buffer = bufnr })
-  end
-  if km.both then
-    vim.keymap.set('n', km.both, function()
-      M.resolve_both(bufnr, config)
-    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 })
+  local maps = {
+    { km.ours, '<Plug>(diffs-conflict-ours)' },
+    { km.theirs, '<Plug>(diffs-conflict-theirs)' },
+    { km.both, '<Plug>(diffs-conflict-both)' },
+    { km.none, '<Plug>(diffs-conflict-none)' },
+    { km.next, '<Plug>(diffs-conflict-next)' },
+    { km.prev, '<Plug>(diffs-conflict-prev)' },
+  }
+
+  for _, map in ipairs(maps) do
+    if map[1] then
+      vim.keymap.set('n', map[1], map[2], { buffer = bufnr })
+    end
   end
 end
 
diff --git a/plugin/diffs.lua b/plugin/diffs.lua
index e4fc690..5d3c8b2 100644
--- a/plugin/diffs.lua
+++ b/plugin/diffs.lua
@@ -57,3 +57,28 @@ 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' })

From a2053a132bc0cccf5ab7d9247c047ea90beddd9d Mon Sep 17 00:00:00 2001
From: Barrett Ruth <62671086+barrettruth@users.noreply.github.com>
Date: Mon, 9 Feb 2026 12:21:13 -0500
Subject: [PATCH 3/4] feat: unified diff conflict resolution for unmerged files
 (#99)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

## Problem

Pressing `du` on a `UU` (unmerged) file in the fugitive status buffer
had no
effect. There was no way to see a proper ours-vs-theirs diff with syntax
highlighting and intra-line changes, or to resolve conflicts from within
a
unified diff view.

Additionally, pressing `du` on a section header containing only unmerged
files
showed "no changes in section" because `git diff` produces combined
(`diff --cc`)
output for unmerged files, which was stripped entirely.

## Solution

Fetch `:2:` (ours) and `:3:` (theirs) from the git index and generate a
standard
unified diff. The existing highlight pipeline (treesitter + intra-line)
applies
automatically. Resolution keymaps (`doo`/`dot`/`dob`/`don`) on hunks in
the diff
view write changes back to the working file's conflict markers.
Navigation
(`]x`/`[x`) jumps between unresolved conflict hunks.

For section diffs, combined diff entries are now replaced with generated
ours-vs-theirs unified diffs instead of being stripped.

Works for merge, cherry-pick, and rebase conflicts — git populates
`:2:`/`:3:`
the same way for all three.

Closes #61
---
 doc/diffs.nvim.txt     |  52 ++++
 lua/diffs/commands.lua |  75 ++++-
 lua/diffs/conflict.lua |  22 +-
 lua/diffs/fugitive.lua |  31 +-
 lua/diffs/merge.lua    | 374 +++++++++++++++++++++++
 plugin/diffs.lua       |  25 ++
 spec/commands_spec.lua |  72 +++++
 spec/merge_spec.lua    | 664 +++++++++++++++++++++++++++++++++++++++++
 8 files changed, 1287 insertions(+), 28 deletions(-)
 create mode 100644 lua/diffs/merge.lua
 create mode 100644 spec/merge_spec.lua

diff --git a/doc/diffs.nvim.txt b/doc/diffs.nvim.txt
index 7663150..6bd848c 100644
--- a/doc/diffs.nvim.txt
+++ b/doc/diffs.nvim.txt
@@ -315,6 +315,32 @@ Example configuration: >lua
     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://`
@@ -345,6 +371,7 @@ 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
@@ -458,6 +485,31 @@ 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*
 
diff --git a/lua/diffs/commands.lua b/lua/diffs/commands.lua
index dc6cfe2..01f1d3a 100644
--- a/lua/diffs/commands.lua
+++ b/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
diff --git a/lua/diffs/conflict.lua b/lua/diffs/conflict.lua
index 9e62a15..894c0b8 100644
--- a/lua/diffs/conflict.lua
+++ b/lua/diffs/conflict.lua
@@ -199,7 +199,7 @@ 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 +211,7 @@ 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 +244,8 @@ 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)
-  refresh(bufnr, config)
+  M.replace_region(bufnr, region, lines)
+  M.refresh(bufnr, config)
 end
 
 ---@param bufnr integer
@@ -262,8 +262,8 @@ 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)
-  refresh(bufnr, config)
+  M.replace_region(bufnr, region, lines)
+  M.refresh(bufnr, config)
 end
 
 ---@param bufnr integer
@@ -288,8 +288,8 @@ function M.resolve_both(bufnr, config)
   for _, l in ipairs(theirs) do
     table.insert(combined, l)
   end
-  replace_region(bufnr, region, combined)
-  refresh(bufnr, config)
+  M.replace_region(bufnr, region, combined)
+  M.refresh(bufnr, config)
 end
 
 ---@param bufnr integer
@@ -305,8 +305,8 @@ function M.resolve_none(bufnr, config)
   if not region then
     return
   end
-  replace_region(bufnr, region, {})
-  refresh(bufnr, config)
+  M.replace_region(bufnr, region, {})
+  M.refresh(bufnr, config)
 end
 
 ---@param bufnr integer
@@ -417,7 +417,7 @@ function M.attach(bufnr, config)
       if not attached_buffers[bufnr] then
         return true
       end
-      refresh(bufnr, config)
+      M.refresh(bufnr, config)
     end,
   })
 
diff --git a/lua/diffs/fugitive.lua b/lua/diffs/fugitive.lua
index a588a22..b11985c 100644
--- a/lua/diffs/fugitive.lua
+++ b/lua/diffs/fugitive.lua
@@ -27,19 +27,19 @@ function M.get_section_at_line(bufnr, lnum)
 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 vim.trim(new), vim.trim(old), 'R'
   end
 
-  local filename = line:match('^[MADRCU?][MADRCU%s]*%s+(.+)$')
-  if filename then
-    return vim.trim(filename), nil
+  local status, filename = line:match('^([MADRCU?])[MADRCU%s]*%s+(.+)$')
+  if status and filename then
+    return vim.trim(filename), nil, status
   end
 
-  return nil, nil
+  return nil, nil, nil
 end
 
 ---@param line string
@@ -57,34 +57,34 @@ 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 +92,7 @@ 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 +150,7 @@ 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 +192,7 @@ 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,
   })
diff --git a/lua/diffs/merge.lua b/lua/diffs/merge.lua
new file mode 100644
index 0000000..9bb9d68
--- /dev/null
+++ b/lua/diffs/merge.lua
@@ -0,0 +1,374 @@
+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.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.api.nvim_win_set_cursor(0, { candidates[#candidates].start_line + 1, 0 })
+end
+
+---@param bufnr integer
+---@param config diffs.ConflictConfig
+function M.setup_keymaps(bufnr, config)
+  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
+
+  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
diff --git a/plugin/diffs.lua b/plugin/diffs.lua
index 5d3c8b2..face556 100644
--- a/plugin/diffs.lua
+++ b/plugin/diffs.lua
@@ -82,3 +82,28 @@ 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' })
diff --git a/spec/commands_spec.lua b/spec/commands_spec.lua
index daba5d5..1bf9e61 100644
--- a/spec/commands_spec.lua
+++ b/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 = {
diff --git a/spec/merge_spec.lua b/spec/merge_spec.lua
new file mode 100644
index 0000000..2f788a6
--- /dev/null
+++ b/spec/merge_spec.lua
@@ -0,0 +1,664 @@
+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,
+    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_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('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('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('parse_file_line returns status for modified 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)',
+        'M  file.lua',
+      })
+      local _, _, _, _, status = fugitive.get_file_at_line(buf, 2)
+      assert.are.equal('M', 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)

From 3c3b27a2cb17b529e766b80fcdc9f04df78d3311 Mon Sep 17 00:00:00 2001
From: Barrett Ruth <br.barrettruth@gmail.com>
Date: Mon, 9 Feb 2026 12:36:51 -0500
Subject: [PATCH 4/4] perf: cache repo root and harden async paths

Problem: get_repo_root() shells out on every call, causing 4-6
redundant subprocesses per gdiff_file() invocation.
highlight_vim_syntax() leaks a scratch buffer if nvim_buf_call errors.
lib.ensure() silently drops callbacks during download, permanently
missing intra-line highlights. The debounce timer callback can operate
on an invalid buffer.

Solution: Cache get_repo_root() results by parent directory. Wrap
nvim_buf_call and nvim_buf_delete in pcall so the scratch buffer is
always cleaned up. Queue pending callbacks in lib.ensure() so all
callers receive the handle once the download completes. Guard the
debounce timer callback with nvim_buf_is_valid.
---
 lua/diffs/git.lua       |  6 ++++++
 lua/diffs/highlight.lua |  4 ++--
 lua/diffs/init.lua      |  4 +++-
 lua/diffs/lib.lua       | 30 +++++++++++++++++++-----------
 4 files changed, 30 insertions(+), 14 deletions(-)

diff --git a/lua/diffs/git.lua b/lua/diffs/git.lua
index 7695283..1aa6328 100644
--- a/lua/diffs/git.lua
+++ b/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
 
diff --git a/lua/diffs/highlight.lua b/lua/diffs/highlight.lua
index 306b0e5..6cdfe92 100644
--- a/lua/diffs/highlight.lua
+++ b/lua/diffs/highlight.lua
@@ -238,7 +238,7 @@ 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')
 
@@ -256,7 +256,7 @@ 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 extmark_count = 0
diff --git a/lua/diffs/init.lua b/lua/diffs/init.lua
index cdc29d1..69a5cf9 100644
--- a/lua/diffs/init.lua
+++ b/lua/diffs/init.lua
@@ -200,7 +200,9 @@ 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
diff --git a/lua/diffs/lib.lua b/lua/diffs/lib.lua
index 5b3254b..8376925 100644
--- a/lua/diffs/lib.lua
+++ b/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')
-    callback(nil)
+    dbg('download already in progress, queued callback')
     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)
-        return
+      else
+        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')
-      if f then
-        f:write(EXPECTED_VERSION)
-        f:close()
+      local cbs = pending_callbacks
+      pending_callbacks = {}
+      for _, cb in ipairs(cbs) do
+        cb(handle)
       end
-
-      vim.notify('[diffs] libvscode_diff downloaded', vim.log.levels.INFO)
-      callback(M.load())
     end)
   end)
 end