refactor(gitcommit): improve commit message handling and buffer management

- Enhance buffer setup to handle git commit --verbose mode
- Improve commit message insertion logic for different buffer scenarios
- Add robust handling of verbose diff separator in commit buffers
- Implement commit message cleaning to remove markdown code blocks
- Optimize buffer content management during commit message generation

Author: jinzhongjia

lua/codecompanion/_extensions/gitcommit/buffer.lua

@@ -48,10 +48,24 @@ function Buffer.setup(opts)
             return false
           end
 
-          -- Check if buffer already has commit message
           local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
+
+          -- Find the verbose diff separator line (git commit --verbose adds this)
+          -- Format: "# ------------------------ >8 ------------------------"
+          local verbose_separator_line = nil
+          for i, line in ipairs(lines) do
+            if line:match("^#.*%-%-%-+%s*>8%s*%-%-%-+") then
+              verbose_separator_line = i
+              break
+            end
+          end
+
+          -- Check if buffer already has commit message
+          -- Only check lines before the verbose separator (if present)
+          local check_end = verbose_separator_line or #lines
           local has_message = false
-          for _, line in ipairs(lines) do
+          for i = 1, check_end do
+            local line = lines[i]
             if not line:match("^%s*#") and vim.trim(line) ~= "" then
               has_message = true
               break
@@ -199,9 +213,6 @@ function Buffer._generate_and_insert_commit_message(bufnr)
   end)
 end
 
----Insert commit message into gitcommit buffer
----@param bufnr number Buffer number
----@param message string Commit message to insert
 function Buffer._insert_commit_message(bufnr, message)
   if not vim.api.nvim_buf_is_valid(bufnr) then
     vim.notify("Buffer is no longer valid", vim.log.levels.ERROR)
@@ -211,45 +222,33 @@ function Buffer._insert_commit_message(bufnr, message)
   -- Get current buffer content
   local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
 
-  -- Find first line that doesn't start with # (comment)
-  -- This is where we'll insert commit message
-  local insert_line = 0
+  -- Find verbose diff separator (git commit --verbose)
+  local verbose_separator_line = nil
   for i, line in ipairs(lines) do
-    if not line:match("^%s*#") and vim.trim(line) == "" then
-      insert_line = i - 1
-      break
-    elseif not line:match("^%s*#") and vim.trim(line) ~= "" then
-      -- Found non-comment, non-empty line, insert before
-      insert_line = i - 1
+    if line:match("^#.*%-%-%-+%s*>8%s*%-%-%-+") then
+      verbose_separator_line = i
       break
     end
   end
 
-  -- Split message into lines
-  local message_lines = vim.split(message, "\n")
-
-  -- Remove existing commit message if present
+  -- Find first comment line (or verbose separator if present)
+  -- This is where we'll insert commit message
   local first_comment_line = nil
-  for i, line in ipairs(lines) do
+  local check_end = verbose_separator_line or #lines
+  for i = 1, check_end do
+    local line = lines[i]
     if line:match("^%s*#") then
-      first_comment_line = i - 1
+      first_comment_line = i
       break
     end
   end
 
-  if first_comment_line then
-    -- Remove non-comment lines before first comment
-    local non_comment_lines = {}
-    for i = 1, first_comment_line do
-      if not lines[i]:match("^%s*#") and vim.trim(lines[i]) ~= "" then
-        -- This is non-comment line, might be existing commit message
-      else
-        table.insert(non_comment_lines, lines[i])
-      end
-    end
+  -- Split message into lines
+  local message_lines = vim.split(message, "\n")
 
-    -- Clear buffer and insert new content
-    vim.api.nvim_buf_set_lines(bufnr, 0, first_comment_line, false, {})
+  if first_comment_line then
+    -- Remove any existing commit message (non-comment lines before first comment)
+    vim.api.nvim_buf_set_lines(bufnr, 0, first_comment_line - 1, false, {})
   end
 
   -- Insert new commit message at beginning

lua/codecompanion/_extensions/gitcommit/generator.lua

@@ -73,7 +73,8 @@ local function send_http_request(client, adapter, payload, callback)
     on_done = function()
       if not has_error then
         if accumulated ~= "" then
-          callback(vim.trim(accumulated), nil)
+          local cleaned = Generator._clean_commit_message(accumulated)
+          callback(cleaned, nil)
         else
           callback(nil, "Generated content is empty")
         end
@@ -116,7 +117,8 @@ local function send_acp_request(client, adapter, messages, callback)
     :on_complete(function(stop_reason)
       if not has_error and accumulated ~= "" then
         -- ACP responses are plain text, wrap in expected format
-        callback(vim.trim(accumulated), nil)
+        local cleaned = Generator._clean_commit_message(accumulated)
+        callback(cleaned, nil)
       elseif not has_error then
         callback(nil, "ACP returned empty response")
       end
@@ -128,6 +130,24 @@ local function send_acp_request(client, adapter, messages, callback)
     :send()
 end
 
+---Clean commit message by removing markdown code blocks and extra formatting
+---@param message string Raw message from LLM
+---@return string cleaned_message The cleaned commit message
+function Generator._clean_commit_message(message)
+  local cleaned = vim.trim(message)
+
+  -- Remove markdown code blocks (```...``` or ````...````)
+  -- Match opening code fence with optional language identifier
+  cleaned = cleaned:gsub("^```+%w*\n", "")
+  -- Match closing code fence
+  cleaned = cleaned:gsub("\n```+$", "")
+
+  -- Trim again after removing code blocks
+  cleaned = vim.trim(cleaned)
+
+  return cleaned
+end
+
 ---@param commit_history? string[] Array of recent commit messages for context (optional)
 function Generator.generate_commit_message(diff, lang, commit_history, callback)
   -- 1. Resolve adapter
@@ -213,35 +233,26 @@ CRITICAL FORMAT REQUIREMENTS:
 1. MUST generate exactly ONE commit message, never multiple messages
 2. MUST include a title line and at least one bullet point description
 3. MUST analyze ALL changes in the diff as a single logical unit
-4. MUST respond with ONLY the commit message, no explanations or extra text
+4. MUST respond with ONLY the commit message, no explanations, markdown code blocks, or extra text
+5. DO NOT wrap the output in markdown code blocks (```) or any other formatting
 
 MANDATORY FORMAT:
 type(scope): brief description
 
-- detailed description point 1
-- detailed description point 2 (if needed)
-- detailed description point 3 (if needed)
 
 Types: feat, fix, docs, style, refactor, perf, test, chore
 Language: %s
 
 RULES:
-- Title: Use imperative mood ("add" not "added"), keep under 50 characters
-- Body: At least ONE bullet point describing the changes
-- For large diffs: Focus on the most significant changes, group related changes
+ - Output the commit message directly without any markdown formatting or code blocks
  - If commit history is provided, follow the established patterns and style from recent commits
 
 REQUIRED EXAMPLES:
 feat(auth): add OAuth2 integration
 
-- implement Google OAuth provider
-- update user authentication flow
-- add integration tests
 
 fix(api): resolve data validation issues
 
-- fix null pointer exceptions in user data
-- improve input validation for API endpoints
 
 Generate ONE complete commit message for this diff:
 ```diff