feat: fix highlighting

doc/fugitive-ts.nvim.txt

@@ -66,9 +66,11 @@ CONFIGURATION                                               *fugitive-ts-config*
                              this many lines. Prevents lag on massive diffs.
 
         {conceal_prefixes}   (boolean, default: true)
-                             Hide diff prefixes (`+`/`-`/` `) using extmark
+                             Hide diff prefixes (`+`/`-`/` `) using virtual
-                             conceal. Makes code appear without the leading
+                             text overlay. Makes code appear without the
-                             diff character.
+                             leading diff character. When `highlights.background`
+                             is also enabled, the overlay inherits the line's
+                             background color.
 
         {highlights}         (table, default: see below)
                              Controls which highlight features are enabled.
@@ -79,23 +81,22 @@ CONFIGURATION                                               *fugitive-ts-config*
         {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
+                             Apply background highlighting to `+`/`-` lines
-                             `DiffDelete` background to `-` lines.
+                             using `FugitiveTsAdd`/`FugitiveTsDelete` groups
+                             (derived from `DiffAdd`/`DiffDelete` backgrounds).
 
         {linenr}             (boolean, default: true)
-                             Highlight line numbers with `DiffAdd`/`DiffDelete`
+                             Highlight line numbers with matching colors.
-                             colors matching the line background.
+                             Only visible if line numbers are enabled.
 
         {vim}                (boolean, default: false)
                              Experimental: Use vim syntax highlighting as
                              fallback when no treesitter parser is available.
 
+    Note: Header context (e.g., `@@ -10,3 +10,4 @@ func()`) is always
+    highlighted with treesitter when a parser is available.
+
 ==============================================================================
 API                                                            *fugitive-ts-api*
 
@@ -129,10 +130,10 @@ 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
+   - Background extmarks (`FugitiveTsAdd`/`FugitiveTsDelete`) at priority 198
    - `Normal` extmarks at priority 199 clear underlying diff foreground
    - Treesitter highlights are applied as extmarks at priority 200
-   - Conceal extmarks hide diff prefixes when `conceal_prefixes` is enabled
+   - Virtual text overlays hide diff prefixes when `conceal_prefixes` is enabled
 4. Re-highlighting occurs on `TextChanged` (debounced) and `Syntax` events
 
 ==============================================================================

lua/fugitive-ts/highlight.lua

@@ -119,7 +119,7 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
     return
   end
 
-  if opts.highlights.headers and hunk.header_context and hunk.header_context_col then
+  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,
@@ -138,15 +138,19 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
     local line_len = #line
     local prefix = line:sub(1, 1)
 
+    local is_diff_line = prefix == '+' or prefix == '-'
+    local line_hl = is_diff_line and (prefix == '+' and 'FugitiveTsAdd' or 'FugitiveTsDelete')
+      or nil
+
     if opts.conceal_prefixes then
+      local virt_hl = (opts.highlights.background and line_hl) or nil
       pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, {
-        end_col = 1,
+        virt_text = { { ' ', virt_hl } },
-        conceal = '',
+        virt_text_pos = 'overlay',
       })
     end
 
-    if opts.highlights.background and (prefix == '+' or prefix == '-') then
+    if opts.highlights.background and is_diff_line then
-      local line_hl = prefix == '+' and 'FugitiveTsAdd' or 'FugitiveTsDelete'
       local extmark_opts = {
         line_hl_group = line_hl,
         priority = 198,

lua/fugitive-ts/init.lua

@@ -1,6 +1,5 @@
 ---@class fugitive-ts.Highlights
 ---@field treesitter boolean
----@field headers boolean
 ---@field background boolean
 ---@field linenr boolean
 ---@field vim boolean
@@ -37,7 +36,6 @@ local default_config = {
   conceal_prefixes = true,
   highlights = {
     treesitter = true,
-    headers = true,
     background = true,
     linenr = true,
     vim = false,
@@ -173,7 +171,6 @@ function M.setup(opts)
   if opts.highlights then
     vim.validate({
       ['highlights.treesitter'] = { opts.highlights.treesitter, 'boolean', true },
-      ['highlights.headers'] = { opts.highlights.headers, 'boolean', true },
       ['highlights.background'] = { opts.highlights.background, 'boolean', true },
       ['highlights.linenr'] = { opts.highlights.linenr, 'boolean', true },
       ['highlights.vim'] = { opts.highlights.vim, 'boolean', true },

spec/highlight_spec.lua

@@ -35,7 +35,6 @@ describe('highlight', function()
         conceal_prefixes = false,
         highlights = {
           treesitter = true,
-          headers = false,
           background = false,
           linenr = false,
           vim = false,
@@ -164,7 +163,7 @@ describe('highlight', function()
         lines = { ' local x = 1', '+local y = 2' },
       }
 
-      highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ highlights = { headers = true } }))
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts())
 
       local extmarks = get_extmarks(bufnr)
       local has_header_extmark = false
@@ -178,9 +177,9 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('does not highlight header when disabled', function()
+    it('does not highlight header when no header_context', function()
       local bufnr = create_buffer({
-        '@@ -10,3 +10,4 @@ function hello()',
+        '@@ -10,3 +10,4 @@',
         ' local x = 1',
       })
 
@@ -188,8 +187,6 @@ describe('highlight', function()
         filename = 'test.lua',
         lang = 'lua',
         start_line = 1,
-        header_context = 'function hello()',
-        header_context_col = 18,
         lines = { ' local x = 1' },
       }
 
@@ -244,7 +241,7 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('applies conceal extmarks when conceal_prefixes enabled', function()
+    it('applies overlay extmarks when conceal_prefixes enabled', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
         ' local x = 1',
@@ -261,17 +258,17 @@ describe('highlight', function()
       highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ conceal_prefixes = true }))
 
       local extmarks = get_extmarks(bufnr)
-      local conceal_count = 0
+      local overlay_count = 0
       for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].conceal == '' then
+        if mark[4] and mark[4].virt_text_pos == 'overlay' then
-          conceal_count = conceal_count + 1
+          overlay_count = overlay_count + 1
         end
       end
-      assert.are.equal(2, conceal_count)
+      assert.are.equal(2, overlay_count)
       delete_buffer(bufnr)
     end)
 
-    it('does not apply conceal extmarks when conceal_prefixes disabled', function()
+    it('does not apply overlay extmarks when conceal_prefixes disabled', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
         ' local x = 1',
@@ -288,13 +285,13 @@ describe('highlight', function()
       highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ conceal_prefixes = false }))
 
       local extmarks = get_extmarks(bufnr)
-      local conceal_count = 0
+      local overlay_count = 0
       for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].conceal == '' then
+        if mark[4] and mark[4].virt_text_pos == 'overlay' then
-          conceal_count = conceal_count + 1
+          overlay_count = overlay_count + 1
         end
       end
-      assert.are.equal(0, conceal_count)
+      assert.are.equal(0, overlay_count)
       delete_buffer(bufnr)
     end)
 

spec/init_spec.lua

@@ -27,7 +27,6 @@ describe('fugitive-ts', function()
           conceal_prefixes = false,
           highlights = {
             treesitter = true,
-            headers = false,
             background = true,
             linenr = true,
             vim = false,