feat(gitcommit): add auto-generate commit message option for gitcommit buffer

- introduce `auto_generate` and `auto_generate_delay` options to buffer config
- automatically generate commit message on entering gitcommit buffer if enabled
- update README with new configuration and workflow details
- update type definitions for new buffer options

Author: jinzhongjia

README.md

@@ -34,6 +34,8 @@ require("codecompanion").setup({
         buffer = {
           enabled = true,        -- Enable gitcommit buffer keymaps
           keymap = "<leader>gc", -- Keymap for generating commit message in gitcommit buffer
+          auto_generate = true,  -- Automatically generate message on entering gitcommit buffer
+          auto_generate_delay = 100, -- Delay in ms before auto-generating
         }
       }
     }
@@ -51,9 +53,10 @@ require("codecompanion").setup({
 ### GitCommit Buffer Integration
 
 When you run `git commit` or open a gitcommit buffer:
-1. Press `<leader>gc` (or your configured keymap) in normal mode
-2. The extension will automatically generate a commit message based on staged changes
-3. The generated message will be inserted directly into the commit buffer
+
+1.  If `buffer.auto_generate` is `true`, the commit message will be generated and inserted automatically.
+2.  If `buffer.auto_generate` is `false` (default), press `<leader>gc` (or your configured keymap) in normal mode to trigger generation.
+3.  The generated message will be inserted directly into the commit buffer.
 
 ### Slash Command (if enabled)
 
@@ -111,6 +114,7 @@ lua/codecompanion/_extensions/gitcommit/
 ## Module Overview
 
 ### `git.lua`
+
 Handles all git-related operations:
 
 - Repository detection with filesystem and git command fallback
@@ -120,6 +124,7 @@ Handles all git-related operations:
 - Commit execution with proper error handling
 
 ### `generator.lua`
+
 Manages LLM interaction:
 
 - Prompt creation for commit message generation with language support
@@ -128,6 +133,7 @@ Manages LLM interaction:
 - Adapter and model configuration
 
 ### `ui.lua`
+
 Provides interactive user interface:
 
 - Floating window display with markdown formatting
@@ -136,6 +142,7 @@ Provides interactive user interface:
 - Responsive window sizing
 
 ### `buffer.lua`
+
 Handles gitcommit buffer integration:
 
 - Automatic keymap setup for gitcommit filetype
@@ -144,20 +151,23 @@ Handles gitcommit buffer integration:
 - Language selection integration
 
 ### `langs.lua`
+
 Manages language selection:
 
 - Multi-language support configuration
 - Interactive language selection UI
 - Language preference handling
 
 ### `types.lua`
+
 Provides type definitions:
 
 - TypeScript-style type annotations for Lua
 - Interface definitions for all modules
 - Configuration option types
 
 ### `init.lua`
+
 Main extension coordinator:
 
 - Module integration and dependency management
@@ -174,6 +184,7 @@ Main extension coordinator:
 ## Workflow
 
 ### Traditional Workflow
+
 1. Stage your changes with `git add`
 2. Run `:CodeCompanionGitCommit`
 3. Review the generated commit message in the floating window
@@ -195,13 +206,15 @@ When the floating window is displayed with the generated commit message, the fol
 - **`q` or `Esc`** - Close the floating window without taking any action
 
 ### GitCommit Buffer Workflow
+
 1. Stage your changes with `git add`
 2. Run `git commit` to open the commit buffer
-3. Press `<leader>gc` in normal mode to generate commit message
-4. The AI-generated message will be inserted into the buffer
-5. Edit if needed and save to complete the commit
+3. If `auto_generate` is enabled, the message appears automatically. Otherwise, press `<leader>gc` in normal mode to generate it.
+4. The AI-generated message will be inserted into the buffer.
+5. Edit if needed and save to complete the commit.
 
 ### Amend Workflow
+
 1. Make additional changes to your files
 2. Stage changes with `git add` (optional, for new changes)
 3. Run `git commit --amend` to open the amend buffer
@@ -223,22 +236,28 @@ opts = {
   buffer = {
     enabled = true,        -- Enable gitcommit buffer keymaps (default: true)
     keymap = "<leader>gc", -- Keymap for generating commit message (default: "<leader>gc")
+    auto_generate = false, -- Automatically generate message on entering gitcommit buffer (default: false)
+    auto_generate_delay = 100, -- Delay in ms before auto-generating (default: 100)
   }
 }
 ```
 
 ### Configuration Options
 
 #### `add_slash_command` (boolean, default: `false`)
+
 When enabled, adds `/gitcommit` slash command to CodeCompanion chat buffers.
 
 #### `adapter` (string, optional)
+
 The LLM adapter to use for generating commit messages. If not specified, defaults to the adapter configured for CodeCompanion's chat strategy.
 
 #### `model` (string, optional)
+
 The specific model to use with the adapter. If not specified, defaults to the model configured for CodeCompanion's chat strategy.
 
 #### `languages` (table, optional)
+
 A list of languages that can be used for generating commit messages. When specified, the extension will prompt you to select a language before generating the commit message. If not provided or empty, commit messages will be generated in English by default.
 
 Example:
@@ -248,12 +267,13 @@ languages = { "English", "简体中文", "日本語", "Français", "Español" }
 ```
 
 #### `exclude_files` (table, optional)
+
 A list of file patterns to exclude from git diff analysis when generating commit messages. Supports glob patterns using `*` and `?` wildcards. This is useful for excluding generated files, minified files, or large files that don't need AI analysis.
 
 Examples:
 
 ```lua
-exclude_files = { 
+exclude_files = {
   "*.pb.go",           -- Protocol buffer generated files
   "*.min.js",          -- Minified JavaScript files
   "package-lock.json", -- NPM lock file
@@ -265,11 +285,21 @@ exclude_files = {
 ```
 
 #### `buffer.enabled` (boolean, default: `true`)
+
 Controls whether gitcommit buffer keymap integration is enabled.
 
 #### `buffer.keymap` (string, default: `"<leader>gc"`)
+
 The keymap used in gitcommit buffers to trigger commit message generation.
 
+#### `buffer.auto_generate` (boolean, default: `false`)
+
+When `true`, automatically generates a commit message upon entering a `gitcommit` buffer, but only if the buffer does not already contain a message (to avoid overwriting during an amend).
+
+#### `buffer.auto_generate_delay` (number, default: `100`)
+
+The delay in milliseconds before the automatic generation is triggered. This helps prevent race conditions with other plugins (like `neogit`) that manage UI elements. You can increase this value if you still experience issues.
+
 ## Contributing
 
-Feel free to submit issues and enhancement requests!
+Feel free to submit issues and enhancement requests!

lua/codecompanion/_extensions/gitcommit/buffer.lua

@@ -9,6 +9,8 @@ local Buffer = {}
 local default_config = {
   enabled = true,
   keymap = "<leader>gc",
+  auto_generate = false,
+  auto_generate_delay = 100, -- Default delay in ms
 }
 
 ---@type table Current configuration
@@ -28,8 +30,40 @@ function Buffer.setup(opts)
     pattern = "gitcommit",
     callback = function(event)
       Buffer._setup_gitcommit_keymap(event.buf)
+
+      if config.auto_generate then
+        -- This autocommand will trigger once when the user enters the gitcommit window.
+        -- This avoids race conditions with plugins like neogit that manage multiple windows.
+        vim.api.nvim_create_autocmd("WinEnter", {
+          buffer = event.buf,
+          once = true,
+          callback = function(args)
+            -- Defer the execution to ensure other plugins (like neogit) have finished their UI setup.
+            vim.defer_fn(function()
+              if not vim.api.nvim_buf_is_valid(args.buf) then
+                return
+              end
+
+              -- Check if buffer already has a commit message (e.g., during amend)
+              local lines = vim.api.nvim_buf_get_lines(args.buf, 0, -1, false)
+              local has_message = false
+              for _, line in ipairs(lines) do
+                if not line:match("^%s*#") and vim.trim(line) ~= "" then
+                  has_message = true
+                  break
+                end
+              end
+
+              if not has_message then
+                Buffer._generate_and_insert_commit_message(args.buf)
+              end
+            end, config.auto_generate_delay)
+          end,
+          desc = "Auto-generate GitCommit message",
+        })
+      end
     end,
-    desc = "Setup GitCommit AI assistant keymap",
+    desc = "Setup GitCommit AI assistant",
   })
 end
 

lua/codecompanion/_extensions/gitcommit/types.lua

@@ -7,6 +7,8 @@
 ---@class CodeCompanion.GitCommit.ExtensionOpts.Buffer
 ---@field enabled boolean Enable buffer-specific keymap for git commit
 ---@field keymap string Keymap for generating commit message in git commit buffer
+---@field auto_generate? boolean Automatically generate commit message on entering gitcommit buffer
+---@field auto_generate_delay? number Delay in ms before auto-generating to avoid race conditions
 
 ---@class CodeCompanion.GitCommit.ExtensionOpts
 ---@field add_slash_command? boolean Add /gitcommit slash command to chat buffer