Don't stage nested repositories when committing with nothing staged

If nothing is staged, committing offers to stage all files first, or
stages them without asking if gui.skipNoStagedFilesWarning is set. Like
staging all files in the files panel, this adds a nested repository as
an embedded repository.

Show why the nested repository can't be staged instead, as staging all
files in the files panel does.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

pkg/gui/controllers/helpers/working_tree_helper.go

@@ -266,6 +266,10 @@ func (self *WorkingTreeHelper) WithEnsureCommittableFiles(handler func() error)
 	}
 
 	if !self.AnyStagedFiles() {
+		if nestedRepository, ok := lo.Find(self.c.Model().Files, (*models.File).IsNestedRepository); ok {
+			return errors.New(self.CantStageNestedRepository(nestedRepository).Text)
+		}
+
 		if self.c.UserConfig().Gui.SkipNoStagedFilesWarning {
 			self.c.LogAction(self.c.Tr.Actions.StageAllFiles)
 			if err := self.c.Git().WorkingTree.StageAll(false); err != nil {

pkg/integration/tests/commit/commit_all_with_nested_repository.go

@@ -0,0 +1,52 @@
+package commit
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var CommitAllWithNestedRepository = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Committing with nothing staged doesn't offer to stage all files if that would stage a nested repository",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+		config.GetUserConfig().Gui.ShowFileTree = false
+	},
+	SetupRepo: func(shell *Shell) {
+		shell.EmptyCommit("first commit")
+		shell.CreateFile("file", "content")
+		shell.RunCommand([]string{"git", "init", "nested"})
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Files().
+			IsFocused().
+			Lines(
+				Equals("?? file").IsSelected(),
+				Equals("?? nested (nested repository)"),
+			).
+			Press(keys.Files.CommitChanges).
+			Tap(func() {
+				t.ExpectPopup().Alert().
+					Title(Equals("Error")).
+					Content(Equals("Can't stage 'nested' because it is a git repository of its own. Discard it with d, or ignore it with i.")).
+					Confirm()
+			}).
+			// Once something is staged, committing works as usual
+			PressPrimaryAction().
+			Press(keys.Files.CommitChanges).
+			Tap(func() {
+				t.ExpectPopup().CommitMessagePanel().
+					Type("add file").
+					Confirm()
+			}).
+			Lines(
+				Equals("?? nested (nested repository)").IsSelected(),
+			)
+
+		t.Views().Commits().
+			Lines(
+				Contains("add file"),
+				Contains("first commit"),
+			)
+	},
+})

pkg/integration/tests/test_list.go

@@ -114,6 +114,7 @@ var tests = []*components.IntegrationTest{
 	commit.CheckoutFileFromRangeSelectionOfCommits,
 	commit.CheckoutFileWithLocalModifications,
 	commit.Commit,
+	commit.CommitAllWithNestedRepository,
 	commit.CommitMultiline,
 	commit.CommitSkipHooks,
 	commit.CommitSwitchToEditor,