fix: checkout out commits fails during bisect

pkg/commands/git_commands/bisect.go

@@ -39,6 +39,12 @@ func (self *BisectCommands) GetInfoForGitDir(gitDir string) *BisectInfo {
 		return info
 	}
 
+	// Get actual HEAD hash to detect when user manually checked out a different commit
+	headHash, err := self.cmd.New(NewGitCmd("rev-parse").Arg("HEAD").ToArgv()).DontLog().RunWithOutput()
+	if err == nil {
+		info.head = strings.TrimSpace(headHash)
+	}
+
 	startContent, err := os.ReadFile(bisectStartPath)
 	if err != nil {
 		self.Log.Infof("error getting git bisect info: %s", err.Error())

pkg/commands/git_commands/bisect_info.go

@@ -34,6 +34,9 @@ type BisectInfo struct {
 
 	// the hash of the commit that's under test
 	current string
+
+	// the actual HEAD hash (may differ from current if user manually checked out a different commit)
+	head string
 }
 
 type BisectStatus int
@@ -63,6 +66,10 @@ func (self *BisectInfo) GetCurrentHash() string {
 	return self.current
 }
 
+func (self *BisectInfo) GetHeadHash() string {
+	return self.head
+}
+
 func (self *BisectInfo) GetStartHash() string {
 	return self.start
 }

pkg/gui/presentation/commits.go

@@ -280,6 +280,8 @@ const (
 	BisectStatusCandidate
 	// also adding this
 	BisectStatusCurrent
+	// BisectStatusHead is shown when user manually checks out a different commit during bisect
+	BisectStatusHead
 )
 
 func getBisectStatus(index int, commitHash string, bisectInfo *git_commands.BisectInfo, bisectBounds *bisectBounds) BisectStatus {
@@ -291,6 +293,13 @@ func getBisectStatus(index int, commitHash string, bisectInfo *git_commands.Bise
 		return BisectStatusCurrent
 	}
 
+	// Check if this is the HEAD commit when it differs from the bisect expected commit
+	// This helps users see where they are when they manually checkout during bisect
+	headHash := bisectInfo.GetHeadHash()
+	if headHash != "" && headHash == commitHash && headHash != bisectInfo.GetCurrentHash() {
+		return BisectStatusHead
+	}
+
 	status, ok := bisectInfo.Status(commitHash)
 	if ok {
 		switch status {
@@ -325,8 +334,9 @@ func getBisectStatusText(bisectStatus BisectStatus, bisectInfo *git_commands.Bis
 	case BisectStatusOld:
 		return style.Sprintf("<-- " + bisectInfo.OldTerm())
 	case BisectStatusCurrent:
-		// TODO: i18n
 		return style.Sprintf("<-- current")
+	case BisectStatusHead:
+		return style.Sprintf("<-- YOU ARE HERE")
 	case BisectStatusSkipped:
 		return style.Sprintf("<-- skipped")
 	case BisectStatusCandidate:
@@ -461,6 +471,8 @@ func getBisectStatusColor(status BisectStatus) style.TextStyle {
 		return style.FgYellow
 	case BisectStatusCurrent:
 		return style.FgMagenta
+	case BisectStatusHead:
+		return style.FgCyan
 	case BisectStatusCandidate:
 		return style.FgBlue
 	}

pkg/integration/tests/bisect/checkout.go

@@ -0,0 +1,74 @@
+package bisect
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var Checkout = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Test checkout during bisect shows HEAD position correctly",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupRepo: func(shell *Shell) {
+		shell.
+			NewBranch("mybranch").
+			CreateNCommits(10)
+	},
+	SetupConfig: func(cfg *config.AppConfig) {
+		cfg.GetUserConfig().Git.Log.ShowGraph = "never"
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		// Start bisect by marking commit 09 as bad and commit 02 as good
+		t.Views().Commits().
+			Focus().
+			SelectedLine(Contains("CI commit 10")).
+			NavigateToLine(Contains("CI commit 09")).
+			Press(keys.Commits.ViewBisectOptions)
+
+		t.ExpectPopup().Menu().Title(Equals("Bisect")).Select(MatchesRegexp(`Mark .* as bad`)).Confirm()
+
+		t.Views().Information().Content(Contains("Bisecting"))
+
+		t.Views().Commits().
+			IsFocused().
+			NavigateToLine(Contains("CI commit 02")).
+			Press(keys.Commits.ViewBisectOptions)
+
+		t.ExpectPopup().Menu().Title(Equals("Bisect")).Select(MatchesRegexp(`Mark .* as good`)).Confirm()
+
+		// Now we're bisecting, we should be at commit 05 (the midpoint)
+		t.Views().Commits().
+			IsFocused().
+			SelectedLine(Contains("CI commit 05").Contains("<-- current"))
+
+		// Try to checkout a different commit (commit 03)
+		t.Views().Commits().
+			NavigateToLine(Contains("CI commit 03")).
+			PressPrimaryAction()
+
+		// The checkout menu should appear
+		t.ExpectPopup().Menu().
+			Title(Contains("Checkout branch or commit")).
+			Select(MatchesRegexp("Checkout commit .* as detached head")).
+			Confirm()
+
+		// After checkout, focus moves to branches panel
+		t.Views().Branches().
+			IsFocused()
+
+		// Now go back to commits panel and verify HEAD position is shown
+		t.Views().Commits().
+			Focus().
+			// Commit 05 should still show "<-- current" (bisect expected)
+			// Commit 03 should show "<-- YOU ARE HERE" (actual HEAD position)
+			Content(
+				Contains("<-- bad").
+					Contains("<-- current").
+					Contains("<-- YOU ARE HERE").
+					Contains("<-- good"),
+			)
+
+		// Bisect should still be active
+		t.Views().Information().Content(Contains("Bisecting"))
+	},
+})

pkg/integration/tests/test_list.go

@@ -36,6 +36,7 @@ import (
 
 var tests = []*components.IntegrationTest{
 	bisect.Basic,
+	bisect.Checkout,
 	bisect.ChooseTerms,
 	bisect.FromOtherBranch,
 	bisect.Skip,