feat: highlights

doc/fugitive-ts.nvim.txt

@@ -56,11 +56,6 @@ CONFIGURATION                                               *fugitive-ts-config*
                              Example: >lua
                                  disabled_languages = { 'markdown', 'text' }
 <
-        {highlight_headers}  (boolean, default: true)
-                             Highlight function context in hunk headers.
-                             The context portion of `@@ -10,3 +10,4 @@ func()`
-                             will receive treesitter highlighting.
-
         {debounce_ms}        (integer, default: 50)
                              Debounce delay in milliseconds for re-highlighting
                              after buffer changes. Lower values feel snappier
@@ -70,6 +65,37 @@ CONFIGURATION                                               *fugitive-ts-config*
                              Skip treesitter highlighting for hunks larger than
                              this many lines. Prevents lag on massive diffs.
 
+        {conceal_prefixes}   (boolean, default: true)
+                             Hide diff prefixes (`+`/`-`/` `) using extmark
+                             conceal. Makes code appear without the leading
+                             diff character.
+
+        {highlights}         (table, default: see below)
+                             Controls which highlight features are enabled.
+                             See |fugitive-ts.Highlights| for fields.
+
+                                                       *fugitive-ts.Highlights*
+    Highlights table fields: ~
+        {treesitter}         (boolean, default: true)
+                             Apply treesitter syntax highlighting to code.
+
+        {headers}            (boolean, default: true)
+                             Highlight function context in hunk headers.
+                             The context portion of `@@ -10,3 +10,4 @@ func()`
+                             will receive treesitter highlighting.
+
+        {background}         (boolean, default: true)
+                             Apply `DiffAdd` background to `+` lines and
+                             `DiffDelete` background to `-` lines.
+
+        {linenr}             (boolean, default: true)
+                             Highlight line numbers with `DiffAdd`/`DiffDelete`
+                             colors matching the line background.
+
+        {vim}                (boolean, default: false)
+                             Experimental: Use vim syntax highlighting as
+                             fallback when no treesitter parser is available.
+
 ==============================================================================
 API                                                            *fugitive-ts-api*
 
@@ -103,8 +129,10 @@ IMPLEMENTATION                                    *fugitive-ts-implementation*
    - Language is detected from the filename using |vim.filetype.match()|
    - Diff prefixes (`+`/`-`/` `) are stripped from code lines
    - Code is parsed with |vim.treesitter.get_string_parser()|
+   - Background extmarks (`DiffAdd`/`DiffDelete`) applied at priority 198
+   - `Normal` extmarks at priority 199 clear underlying diff foreground
    - Treesitter highlights are applied as extmarks at priority 200
-   - A `Normal` extmark at priority 199 clears underlying diff colors
+   - Conceal extmarks hide diff prefixes when `conceal_prefixes` is enabled
 4. Re-highlighting occurs on `TextChanged` (debounced) and `Syntax` events
 
 ==============================================================================

lua/fugitive-ts/highlight.lua

@@ -55,26 +55,30 @@ local function highlight_text(bufnr, ns, hunk, col_offset, text, lang, debug)
   return extmark_count
 end
 
+---@class fugitive-ts.HunkOpts
+---@field max_lines integer
+---@field conceal_prefixes boolean
+---@field highlights fugitive-ts.Highlights
+---@field debug boolean
+
 ---@param bufnr integer
 ---@param ns integer
 ---@param hunk fugitive-ts.Hunk
----@param max_lines integer
+---@param opts fugitive-ts.HunkOpts
----@param highlight_headers boolean
+function M.highlight_hunk(bufnr, ns, hunk, opts)
----@param debug? boolean
-function M.highlight_hunk(bufnr, ns, hunk, max_lines, highlight_headers, debug)
   local lang = hunk.lang
   if not lang then
     return
   end
 
-  if #hunk.lines > max_lines then
+  if #hunk.lines > opts.max_lines then
-    if debug then
+    if opts.debug then
       dbg(
         'skipping hunk %s:%d (%d lines > %d max)',
         hunk.filename,
         hunk.start_line,
         #hunk.lines,
-        max_lines
+        opts.max_lines
       )
     end
     return
@@ -93,7 +97,7 @@ function M.highlight_hunk(bufnr, ns, hunk, max_lines, highlight_headers, debug)
 
   local ok, parser_obj = pcall(vim.treesitter.get_string_parser, code, lang)
   if not ok or not parser_obj then
-    if debug then
+    if opts.debug then
       dbg('failed to create parser for lang: %s', lang)
     end
     return
@@ -101,7 +105,7 @@ function M.highlight_hunk(bufnr, ns, hunk, max_lines, highlight_headers, debug)
 
   local trees = parser_obj:parse()
   if not trees or #trees == 0 then
-    if debug then
+    if opts.debug then
       dbg('parse returned no trees for lang: %s', lang)
     end
     return
@@ -109,22 +113,29 @@ function M.highlight_hunk(bufnr, ns, hunk, max_lines, highlight_headers, debug)
 
   local query = vim.treesitter.query.get(lang, 'highlights')
   if not query then
-    if debug then
+    if opts.debug then
       dbg('no highlights query for lang: %s', lang)
     end
     return
   end
 
-  if highlight_headers and hunk.header_context and hunk.header_context_col then
+  if opts.highlights.headers and 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 = 'Normal',
       priority = 199,
     })
-    local header_extmarks =
+    local header_extmarks = highlight_text(
-      highlight_text(bufnr, ns, hunk, hunk.header_context_col, hunk.header_context, lang, debug)
+      bufnr,
-    if debug and header_extmarks > 0 then
+      ns,
+      hunk,
+      hunk.header_context_col,
+      hunk.header_context,
+      lang,
+      opts.debug
+    )
+    if opts.debug and header_extmarks > 0 then
       dbg('header %s:%d applied %d extmarks', hunk.filename, hunk.start_line, header_extmarks)
     end
   end
@@ -132,7 +143,28 @@ function M.highlight_hunk(bufnr, ns, hunk, max_lines, highlight_headers, debug)
   for i, line in ipairs(hunk.lines) do
     local buf_line = hunk.start_line + i - 1
     local line_len = #line
-    if line_len > 1 then
+    local prefix = line:sub(1, 1)
+
+    if opts.conceal_prefixes then
+      pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, {
+        end_col = 1,
+        conceal = '',
+      })
+    end
+
+    if opts.highlights.background and (prefix == '+' or prefix == '-') then
+      local line_hl = prefix == '+' and 'DiffAdd' or 'DiffDelete'
+      local extmark_opts = {
+        line_hl_group = line_hl,
+        priority = 198,
+      }
+      if opts.highlights.linenr then
+        extmark_opts.number_hl_group = line_hl
+      end
+      pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, extmark_opts)
+    end
+
+    if line_len > 1 and opts.highlights.treesitter then
       pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 1, {
         end_col = line_len,
         hl_group = 'Normal',
@@ -141,6 +173,10 @@ function M.highlight_hunk(bufnr, ns, hunk, max_lines, highlight_headers, debug)
     end
   end
 
+  if not opts.highlights.treesitter then
+    return
+  end
+
   local extmark_count = 0
   for id, node, _ in query:iter_captures(trees[1]:root(), code) do
     local capture_name = '@' .. query.captures[id]
@@ -160,7 +196,7 @@ function M.highlight_hunk(bufnr, ns, hunk, max_lines, highlight_headers, debug)
     extmark_count = extmark_count + 1
   end
 
-  if debug then
+  if opts.debug then
     dbg('hunk %s:%d applied %d extmarks', hunk.filename, hunk.start_line, extmark_count)
   end
 end

lua/fugitive-ts/init.lua

@@ -1,11 +1,19 @@
+---@class fugitive-ts.Highlights
+---@field treesitter boolean
+---@field headers boolean
+---@field background boolean
+---@field linenr boolean
+---@field vim boolean
+
 ---@class fugitive-ts.Config
 ---@field enabled boolean
 ---@field debug boolean
 ---@field languages table<string, string>
 ---@field disabled_languages string[]
----@field highlight_headers boolean
 ---@field debounce_ms integer
 ---@field max_lines_per_hunk integer
+---@field conceal_prefixes boolean
+---@field highlights fugitive-ts.Highlights
 
 ---@class fugitive-ts
 ---@field attach fun(bufnr?: integer)
@@ -24,9 +32,16 @@ local default_config = {
   debug = false,
   languages = {},
   disabled_languages = {},
-  highlight_headers = true,
   debounce_ms = 50,
   max_lines_per_hunk = 500,
+  conceal_prefixes = true,
+  highlights = {
+    treesitter = true,
+    headers = true,
+    background = true,
+    linenr = true,
+    vim = false,
+  },
 }
 
 ---@type fugitive-ts.Config
@@ -61,14 +76,12 @@ local function highlight_buffer(bufnr)
     parser.parse_buffer(bufnr, config.languages, config.disabled_languages, config.debug)
   dbg('found %d hunks in buffer %d', #hunks, bufnr)
   for _, hunk in ipairs(hunks) do
-    highlight.highlight_hunk(
+    highlight.highlight_hunk(bufnr, ns, hunk, {
-      bufnr,
+      max_lines = config.max_lines_per_hunk,
-      ns,
+      conceal_prefixes = config.conceal_prefixes,
-      hunk,
+      highlights = config.highlights,
-      config.max_lines_per_hunk,
+      debug = config.debug,
-      config.highlight_headers,
+    })
-      config.debug
-    )
   end
 end
 

spec/highlight_spec.lua

@@ -25,6 +25,33 @@ describe('highlight', function()
       return vim.api.nvim_buf_get_extmarks(bufnr, ns, 0, -1, { details = true })
     end
 
+    local function default_opts(overrides)
+      local opts = {
+        max_lines = 500,
+        conceal_prefixes = false,
+        highlights = {
+          treesitter = true,
+          headers = false,
+          background = false,
+          linenr = false,
+          vim = false,
+        },
+        debug = false,
+      }
+      if overrides then
+        for k, v in pairs(overrides) do
+          if k == 'highlights' then
+            for hk, hv in pairs(v) do
+              opts.highlights[hk] = hv
+            end
+          else
+            opts[k] = v
+          end
+        end
+      end
+      return opts
+    end
+
     it('applies extmarks for lua code', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
@@ -39,7 +66,7 @@ describe('highlight', function()
         lines = { ' local x = 1', '+local y = 2' },
       }
 
-      highlight.highlight_hunk(bufnr, ns, hunk, 500, false, false)
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
 
       local extmarks = get_extmarks(bufnr)
       assert.is_true(#extmarks > 0)
@@ -60,7 +87,7 @@ describe('highlight', function()
         lines = { ' local x = 1', '+local y = 2' },
       }
 
-      highlight.highlight_hunk(bufnr, ns, hunk, 500, false, false)
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
 
       local extmarks = get_extmarks(bufnr)
       local has_normal = false
@@ -90,7 +117,7 @@ describe('highlight', function()
         lines = hunk_lines,
       }
 
-      highlight.highlight_hunk(bufnr, ns, hunk, 500, false, false)
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
 
       local extmarks = get_extmarks(bufnr)
       assert.are.equal(0, #extmarks)
@@ -111,7 +138,7 @@ describe('highlight', function()
         lines = { ' some content', '+more content' },
       }
 
-      highlight.highlight_hunk(bufnr, ns, hunk, 500, false, false)
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
 
       local extmarks = get_extmarks(bufnr)
       assert.are.equal(0, #extmarks)
@@ -134,7 +161,7 @@ describe('highlight', function()
         lines = { ' local x = 1', '+local y = 2' },
       }
 
-      highlight.highlight_hunk(bufnr, ns, hunk, 500, true, false)
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ highlights = { headers = true } }))
 
       local extmarks = get_extmarks(bufnr)
       local has_header_extmark = false
@@ -163,7 +190,7 @@ describe('highlight', function()
         lines = { ' local x = 1' },
       }
 
-      highlight.highlight_hunk(bufnr, ns, hunk, 500, false, false)
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
 
       local extmarks = get_extmarks(bufnr)
       local header_extmarks = 0
@@ -189,7 +216,7 @@ describe('highlight', function()
       }
 
       assert.has_no.errors(function()
-        highlight.highlight_hunk(bufnr, ns, hunk, 500, false, false)
+        highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
       end)
       delete_buffer(bufnr)
     end)
@@ -209,9 +236,294 @@ describe('highlight', function()
       }
 
       assert.has_no.errors(function()
-        highlight.highlight_hunk(bufnr, ns, hunk, 500, false, false)
+        highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
       end)
       delete_buffer(bufnr)
     end)
+
+    it('applies conceal extmarks when conceal_prefixes enabled', 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({ conceal_prefixes = true }))
+
+      local extmarks = get_extmarks(bufnr)
+      local conceal_count = 0
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].conceal == '' then
+          conceal_count = conceal_count + 1
+        end
+      end
+      assert.are.equal(2, conceal_count)
+      delete_buffer(bufnr)
+    end)
+
+    it('does not apply conceal extmarks when conceal_prefixes 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({ conceal_prefixes = false }))
+
+      local extmarks = get_extmarks(bufnr)
+      local conceal_count = 0
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].conceal == '' then
+          conceal_count = conceal_count + 1
+        end
+      end
+      assert.are.equal(0, conceal_count)
+      delete_buffer(bufnr)
+    end)
+
+    it('applies DiffAdd background to + lines when background enabled', 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 } })
+      )
+
+      local extmarks = get_extmarks(bufnr)
+      local has_diff_add = false
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].line_hl_group == 'DiffAdd' then
+          has_diff_add = true
+          break
+        end
+      end
+      assert.is_true(has_diff_add)
+      delete_buffer(bufnr)
+    end)
+
+    it('applies DiffDelete background to - lines when background enabled', 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 has_diff_delete = false
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].line_hl_group == 'DiffDelete' then
+          has_diff_delete = true
+          break
+        end
+      end
+      assert.is_true(has_diff_delete)
+      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].line_hl_group then
+          has_line_hl = true
+          break
+        end
+      end
+      assert.is_false(has_line_hl)
+      delete_buffer(bufnr)
+    end)
+
+    it('applies number_hl_group when linenr enabled', 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, linenr = true } })
+      )
+
+      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_true(has_number_hl)
+      delete_buffer(bufnr)
+    end)
+
+    it('does not apply number_hl_group when linenr 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, linenr = 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 = 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 @@',
+        ' 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 = false, background = true } })
+      )
+
+      local extmarks = get_extmarks(bufnr)
+      local has_diff_add = false
+      for _, mark in ipairs(extmarks) do
+        if mark[4] and mark[4].line_hl_group == 'DiffAdd' then
+          has_diff_add = true
+          break
+        end
+      end
+      assert.is_true(has_diff_add)
+      delete_buffer(bufnr)
+    end)
   end)
 end)

spec/init_spec.lua

@@ -22,9 +22,16 @@ describe('fugitive-ts', function()
           debug = true,
           languages = { ['.envrc'] = 'bash' },
           disabled_languages = { 'markdown' },
-          highlight_headers = false,
           debounce_ms = 100,
           max_lines_per_hunk = 1000,
+          conceal_prefixes = false,
+          highlights = {
+            treesitter = true,
+            headers = false,
+            background = true,
+            linenr = true,
+            vim = false,
+          },
         })
       end)
     end)