feat: use conceal overlay

doc/fugitive-ts.nvim.txt

@@ -65,12 +65,10 @@ 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 virtual
-                             text overlay. Makes code appear without the
-                             leading diff character. When `highlights.background`
-                             is also enabled, the overlay inherits the line's
-                             background color.
+        {hide_prefix}        (boolean, default: true)
+                             Hide diff prefixes (`+`/`-`/` `) using conceal.
+                             Makes code appear flush left without the leading
+                             diff character. Sets `conceallevel=2` on attach.
 
         {highlights}         (table, default: see below)
                              Controls which highlight features are enabled.
@@ -133,7 +131,7 @@ IMPLEMENTATION                                    *fugitive-ts-implementation*
    - 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
-   - Virtual text overlays hide diff prefixes when `conceal_prefixes` is enabled
+   - Conceal extmarks hide diff prefixes when `hide_prefix` is enabled
 4. Re-highlighting occurs on `TextChanged` (debounced) and `Syntax` events
 
 ==============================================================================

lua/fugitive-ts/highlight.lua

@@ -66,7 +66,7 @@ end
 
 ---@class fugitive-ts.HunkOpts
 ---@field max_lines integer
----@field conceal_prefixes boolean
+---@field hide_prefix boolean
 ---@field highlights fugitive-ts.Highlights
 
 ---@param bufnr integer
@@ -142,11 +142,10 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
     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
+    if opts.hide_prefix then
       pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, 0, {
-        virt_text = { { ' ', virt_hl } },
-        virt_text_pos = 'overlay',
+        end_col = 1,
+        conceal = '',
       })
     end
 

lua/fugitive-ts/init.lua

@@ -11,7 +11,7 @@
 ---@field disabled_languages string[]
 ---@field debounce_ms integer
 ---@field max_lines_per_hunk integer
----@field conceal_prefixes boolean
+---@field hide_prefix boolean
 ---@field highlights fugitive-ts.Highlights
 
 ---@class fugitive-ts
@@ -33,7 +33,7 @@ local default_config = {
   disabled_languages = {},
   debounce_ms = 50,
   max_lines_per_hunk = 500,
-  conceal_prefixes = true,
+  hide_prefix = true,
   highlights = {
     treesitter = true,
     background = true,
@@ -75,7 +75,7 @@ local function highlight_buffer(bufnr)
   for _, hunk in ipairs(hunks) do
     highlight.highlight_hunk(bufnr, ns, hunk, {
       max_lines = config.max_lines_per_hunk,
-      conceal_prefixes = config.conceal_prefixes,
+      hide_prefix = config.hide_prefix,
       highlights = config.highlights,
     })
   end
@@ -122,6 +122,10 @@ function M.attach(bufnr)
 
   dbg('attaching to buffer %d', bufnr)
 
+  if config.hide_prefix then
+    vim.api.nvim_set_option_value('conceallevel', 2, { win = 0 })
+  end
+
   local debounced = create_debounced_highlight(bufnr)
 
   highlight_buffer(bufnr)
@@ -164,7 +168,7 @@ function M.setup(opts)
     disabled_languages = { opts.disabled_languages, 'table', true },
     debounce_ms = { opts.debounce_ms, 'number', true },
     max_lines_per_hunk = { opts.max_lines_per_hunk, 'number', true },
-    conceal_prefixes = { opts.conceal_prefixes, 'boolean', true },
+    hide_prefix = { opts.hide_prefix, 'boolean', true },
     highlights = { opts.highlights, 'table', true },
   })
 

spec/highlight_spec.lua

@@ -32,7 +32,7 @@ describe('highlight', function()
     local function default_opts(overrides)
       local opts = {
         max_lines = 500,
-        conceal_prefixes = false,
+        hide_prefix = false,
         highlights = {
           treesitter = true,
           background = false,
@@ -241,7 +241,7 @@ describe('highlight', function()
       delete_buffer(bufnr)
     end)
 
-    it('applies overlay extmarks when conceal_prefixes enabled', function()
+    it('applies conceal extmarks when hide_prefix enabled', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
         ' local x = 1',
@@ -255,20 +255,20 @@ describe('highlight', function()
         lines = { ' local x = 1', '+local y = 2' },
       }
 
-      highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ conceal_prefixes = true }))
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ hide_prefix = true }))
 
       local extmarks = get_extmarks(bufnr)
-      local overlay_count = 0
+      local conceal_count = 0
       for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].virt_text_pos == 'overlay' then
-          overlay_count = overlay_count + 1
+        if mark[4] and mark[4].conceal == '' then
+          conceal_count = conceal_count + 1
         end
       end
-      assert.are.equal(2, overlay_count)
+      assert.are.equal(2, conceal_count)
       delete_buffer(bufnr)
     end)
 
-    it('does not apply overlay extmarks when conceal_prefixes disabled', function()
+    it('does not apply conceal extmarks when hide_prefix disabled', function()
       local bufnr = create_buffer({
         '@@ -1,1 +1,2 @@',
         ' local x = 1',
@@ -282,16 +282,16 @@ describe('highlight', function()
         lines = { ' local x = 1', '+local y = 2' },
       }
 
-      highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ conceal_prefixes = false }))
+      highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ hide_prefix = false }))
 
       local extmarks = get_extmarks(bufnr)
-      local overlay_count = 0
+      local conceal_count = 0
       for _, mark in ipairs(extmarks) do
-        if mark[4] and mark[4].virt_text_pos == 'overlay' then
-          overlay_count = overlay_count + 1
+        if mark[4] and mark[4].conceal == '' then
+          conceal_count = conceal_count + 1
         end
       end
-      assert.are.equal(0, overlay_count)
+      assert.are.equal(0, conceal_count)
       delete_buffer(bufnr)
     end)
 

spec/init_spec.lua

@@ -24,7 +24,7 @@ describe('fugitive-ts', function()
           disabled_languages = { 'markdown' },
           debounce_ms = 100,
           max_lines_per_hunk = 1000,
-          conceal_prefixes = false,
+          hide_prefix = false,
           highlights = {
             treesitter = true,
             background = true,