feat(commit): add AI-generated commit message support. (v2)

docs-master/Config.md

@@ -359,6 +359,13 @@ git:
     # If autoWrapCommitMessage is true, the width to wrap to
     autoWrapWidth: 72
 
+    # Shell command that generates a commit message from a diff piped to stdin.
+    # The command's stdout is used as the commit message (markdown fences are
+    # stripped automatically).
+    # Accessible via the commit menu (<c-o> then 'g').
+    # Example: "claude -p 'Generate a conventional commit message for this diff:'"
+    generateCommand: ""
+
   # Config relating to merging
   merging:
     # If true, run merges in a subprocess so that if a commit message is required,

pkg/config/user_config.go

@@ -355,6 +355,11 @@ type CommitConfig struct {
 	AutoWrapCommitMessage bool `yaml:"autoWrapCommitMessage"`
 	// If autoWrapCommitMessage is true, the width to wrap to
 	AutoWrapWidth int `yaml:"autoWrapWidth"`
+	// Shell command that generates a commit message from a diff piped to stdin.
+	// The command's stdout is used as the commit message (markdown fences are stripped automatically).
+	// Accessible via the commit menu (<c-o> then 'g').
+	// Example: "claude -p 'Generate a conventional commit message for this diff:'"
+	GenerateCommand string `yaml:"generateCommand"`
 }
 
 type MergingConfig struct {

pkg/gui/controllers/commit_message_controller.go

@@ -167,6 +167,10 @@ func (self *CommitMessageController) setCommitMessageAtIndex(index int) (bool, e
 }
 
 func (self *CommitMessageController) confirm() error {
+	if self.c.Helpers().Commits.IsGenerating() {
+		return nil
+	}
+
 	// The default keybinding for this action is "<enter>", which means that we
 	// also get here when pasting multi-line text that contains newlines. In
 	// that case we don't want to confirm the commit, but switch to the
@@ -185,6 +189,10 @@ func (self *CommitMessageController) confirm() error {
 }
 
 func (self *CommitMessageController) close() error {
+	if self.c.Helpers().Commits.IsGenerating() {
+		return nil
+	}
+
 	self.c.Helpers().Commits.CloseCommitMessagePanel()
 	return nil
 }

pkg/gui/controllers/helpers/commits_helper.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"path/filepath"
 	"strings"
+	"sync/atomic"
 	"time"
 
 	"github.com/jesseduffield/gocui"
@@ -20,6 +21,13 @@ type CommitsHelper struct {
 	getCommitDescription          func() string
 	getUnwrappedCommitDescription func() string
 	setCommitDescription          func(string)
+
+	// set to 1 while commit message generation is in progress
+	generating atomic.Int32
+}
+
+func (self *CommitsHelper) IsGenerating() bool {
+	return self.generating.Load() == 1
 }
 
 func NewCommitsHelper(
@@ -199,6 +207,13 @@ func (self *CommitsHelper) OpenCommitMenu(suggestionFunc func(string) []*types.S
 		}
 	}
 
+	var disabledReasonForGenerate *types.DisabledReason
+	if self.c.UserConfig().Git.Commit.GenerateCommand == "" {
+		disabledReasonForGenerate = &types.DisabledReason{
+			Text: self.c.Tr.NoGenerateCommandConfigured,
+		}
+	}
+
 	menuItems := []*types.MenuItem{
 		{
 			Label: self.c.Tr.OpenInEditor,
@@ -222,6 +237,14 @@ func (self *CommitsHelper) OpenCommitMenu(suggestionFunc func(string) []*types.S
 			},
 			Key: 'p',
 		},
+		{
+			Label: self.c.Tr.GenerateCommitMessage,
+			OnPress: func() error {
+				return self.generateCommitMessage()
+			},
+			Key:            'g',
+			DisabledReason: disabledReasonForGenerate,
+		},
 	}
 	return self.c.Menu(types.CreateMenuOptions{
 		Title: self.c.Tr.CommitMenuTitle,
@@ -263,3 +286,70 @@ func (self *CommitsHelper) pasteCommitMessageFromClipboard() error {
 		},
 	})
 }
+
+func (self *CommitsHelper) generateCommitMessage() error {
+	self.generating.Store(1)
+	self.c.Views().CommitMessage.Editable = false
+	self.c.Views().CommitDescription.Editable = false
+	originalTitle := self.c.Views().CommitMessage.Title
+	self.c.Views().CommitMessage.Title = self.c.Tr.GeneratingCommitMessageStatus
+
+	restore := func() {
+		self.c.OnUIThread(func() error {
+			self.generating.Store(0)
+			self.c.Views().CommitMessage.Editable = true
+			self.c.Views().CommitDescription.Editable = true
+			self.c.Views().CommitMessage.Title = originalTitle
+			return nil
+		})
+	}
+
+	return self.c.WithWaitingStatus(self.c.Tr.GeneratingCommitMessageStatus, func(_ gocui.Task) error {
+		defer restore()
+
+		diff, err := self.c.Git().Diff.GetDiff(true)
+		if err != nil {
+			return err
+		}
+		if strings.TrimSpace(diff) == "" {
+			self.c.OnUIThread(func() error {
+				self.c.ErrorToast(self.c.Tr.NoStagedChangesForGenerate)
+				return nil
+			})
+			return nil
+		}
+
+		command := self.c.UserConfig().Git.Commit.GenerateCommand
+		message, err := self.c.OS().Cmd.NewShell(command, "").SetStdin(diff).DontLog().RunWithOutput()
+		if err != nil {
+			return err
+		}
+
+		message = parseGenerateOutput(message)
+		if message == "" {
+			return errors.New("generate command returned an empty commit message")
+		}
+
+		self.c.OnUIThread(func() error {
+			self.SetMessageAndDescriptionInView(message)
+			return nil
+		})
+		return nil
+	})
+}
+
+// parseGenerateOutput strips markdown code fences and any preamble before them.
+func parseGenerateOutput(s string) string {
+	s = strings.TrimSpace(s)
+	if start := strings.Index(s, "```"); start >= 0 {
+		rest := s[start:]
+		if idx := strings.Index(rest, "\n"); idx >= 0 {
+			rest = rest[idx+1:]
+		}
+		if idx := strings.LastIndex(rest, "```"); idx >= 0 {
+			rest = rest[:idx]
+		}
+		s = strings.TrimSpace(rest)
+	}
+	return s
+}

pkg/gui/controllers/helpers/commits_helper_test.go

@@ -6,6 +6,50 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestParseAIOutput(t *testing.T) {
+	scenarios := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "plain text unchanged",
+			input:    "feat: add login button",
+			expected: "feat: add login button",
+		},
+		{
+			name:     "strips surrounding whitespace",
+			input:    "  feat: add login button  ",
+			expected: "feat: add login button",
+		},
+		{
+			name:     "strips plain code fence",
+			input:    "```\nfeat: add login button\n```",
+			expected: "feat: add login button",
+		},
+		{
+			name:     "strips fenced block with language tag",
+			input:    "```text\nfeat: add login button\n```",
+			expected: "feat: add login button",
+		},
+		{
+			name:     "strips fenced block with surrounding text",
+			input:    "Here is your commit:\n```\nfeat: add login button\n```\nDone.",
+			expected: "feat: add login button",
+		},
+		{
+			name:     "multiline commit message in fence",
+			input:    "```\nfeat: add login button\n\nCloses #123\n```",
+			expected: "feat: add login button\n\nCloses #123",
+		},
+	}
+	for _, s := range scenarios {
+		t.Run(s.name, func(t *testing.T) {
+			assert.Equal(t, s.expected, parseGenerateOutput(s.input))
+		})
+	}
+}
+
 func TestTryRemoveHardLineBreaks(t *testing.T) {
 	scenarios := []struct {
 		name           string

pkg/i18n/english.go

@@ -672,6 +672,10 @@ type TranslationSet struct {
 	CommitURL                             string
 	PasteCommitMessageFromClipboard       string
 	SurePasteCommitMessage                string
+	GenerateCommitMessage                 string
+	GeneratingCommitMessageStatus         string
+	NoStagedChangesForGenerate            string
+	NoGenerateCommandConfigured           string
 	CommitMessage                         string
 	CommitMessageBody                     string
 	CommitSubject                         string
@@ -1789,6 +1793,10 @@ func EnglishTranslationSet() *TranslationSet {
 		CommitURL:                                "Commit URL",
 		PasteCommitMessageFromClipboard:          "Paste commit message from clipboard",
 		SurePasteCommitMessage:                   "Pasting will overwrite the current commit message, continue?",
+		GenerateCommitMessage:                    "Generate commit message",
+		GeneratingCommitMessageStatus:            "Generating commit message...",
+		NoStagedChangesForGenerate:               "No staged changes to generate a commit message from",
+		NoGenerateCommandConfigured:              "No generate command configured. Set git.commit.generateCommand in your config",
 		CommitMessage:                            "Commit message (subject and body)",
 		CommitMessageBody:                        "Commit message body",
 		CommitSubject:                            "Commit subject",

schema-master/config.json

@@ -19,6 +19,10 @@
           "type": "integer",
           "description": "If autoWrapCommitMessage is true, the width to wrap to",
           "default": 72
+        },
+        "generateCommand": {
+          "type": "string",
+          "description": "Shell command that generates a commit message from a diff piped to stdin.\nThe command's stdout is used as the commit message (markdown fences are stripped automatically).\nAccessible via the commit menu (\u003cc-o\u003e then 'g').\nExample: \"claude -p 'Generate a conventional commit message for this diff:'\""
         }
       },
       "additionalProperties": false,