Allow to switch branches in Commit View (#4115) (#4117)

- **PR Description**

When the user checks out a commit which has a local branch ref attached
to it, they can select between checking out the branch or checking out
the commit as detached head. If no local branch is attached to the
commit, the behavior is like before: They are asked to confirm, if they
want to checkout the commit as detached head.

Requested in #4115.

Note: I tried also to consider remote branches, but because I wasn't
able to correlate remote branches to their commits, I deferred it and
leave it open for later improvement.

pkg/gui/controllers/basic_commits_controller.go

@@ -280,15 +280,7 @@ func (self *BasicCommitsController) createResetMenu(commit *models.Commit) error
 }
 
 func (self *BasicCommitsController) checkout(commit *models.Commit) error {
-	self.c.Confirm(types.ConfirmOpts{
+	return self.c.Helpers().Refs.CreateCheckoutMenu(commit)
-		Title:  self.c.Tr.CheckoutCommit,
-		Prompt: self.c.Tr.SureCheckoutThisCommit,
-		HandleConfirm: func() error {
-			self.c.LogAction(self.c.Tr.Actions.CheckoutCommit)
-			return self.c.Helpers().Refs.CheckoutRef(commit.Hash, types.CheckoutRefOptions{})
-		},
-	})
-	return nil
 }
 
 func (self *BasicCommitsController) copyRange(*models.Commit) error {

pkg/gui/controllers/helpers/refs_helper.go

@@ -18,6 +18,7 @@ type IRefsHelper interface {
 	CheckoutRef(ref string, options types.CheckoutRefOptions) error
 	GetCheckedOutRef() *models.Branch
 	CreateGitResetMenu(ref string) error
+	CreateCheckoutMenu(commit *models.Commit) error
 	ResetToRef(ref string, strength string, envVars []string) error
 	NewBranch(from string, fromDescription string, suggestedBranchname string) error
 }
@@ -271,6 +272,53 @@ func (self *RefsHelper) CreateGitResetMenu(ref string) error {
 	})
 }
 
+func (self *RefsHelper) CreateCheckoutMenu(commit *models.Commit) error {
+	branches := lo.Filter(self.c.Model().Branches, func(branch *models.Branch, _ int) bool {
+		return commit.Hash == branch.CommitHash && branch.Name != self.c.Model().CheckedOutBranch
+	})
+
+	hash := commit.Hash
+	var menuItems []*types.MenuItem
+
+	if len(branches) > 0 {
+		menuItems = append(menuItems, lo.Map(branches, func(branch *models.Branch, index int) *types.MenuItem {
+			var key types.Key
+			if index < 9 {
+				key = rune(index + 1 + '0') // Convert 1-based index to key
+			}
+			return &types.MenuItem{
+				LabelColumns: []string{fmt.Sprintf(self.c.Tr.Actions.CheckoutBranchAtCommit, branch.Name)},
+				OnPress: func() error {
+					self.c.LogAction(self.c.Tr.Actions.CheckoutBranch)
+					return self.CheckoutRef(branch.RefName(), types.CheckoutRefOptions{})
+				},
+				Key: key,
+			}
+		})...)
+	} else {
+		menuItems = append(menuItems, &types.MenuItem{
+			LabelColumns:   []string{self.c.Tr.Actions.CheckoutBranch},
+			OnPress:        func() error { return nil },
+			DisabledReason: &types.DisabledReason{Text: self.c.Tr.NoBranchesFoundAtCommitTooltip},
+			Key:            '1',
+		})
+	}
+
+	menuItems = append(menuItems, &types.MenuItem{
+		LabelColumns: []string{fmt.Sprintf(self.c.Tr.Actions.CheckoutCommitAsDetachedHead, utils.ShortHash(hash))},
+		OnPress: func() error {
+			self.c.LogAction(self.c.Tr.Actions.CheckoutCommit)
+			return self.CheckoutRef(hash, types.CheckoutRefOptions{})
+		},
+		Key: 'd',
+	})
+
+	return self.c.Menu(types.CreateMenuOptions{
+		Title: self.c.Tr.Actions.CheckoutBranchOrCommit,
+		Items: menuItems,
+	})
+}
+
 func (self *RefsHelper) NewBranch(from string, fromFormattedName string, suggestedBranchName string) error {
 	message := utils.ResolvePlaceholderString(
 		self.c.Tr.NewBranchNameBranchOff,

pkg/i18n/english.go

@@ -527,6 +527,7 @@ type TranslationSet struct {
 	FetchingRemoteStatus                  string
 	CheckoutCommit                        string
 	CheckoutCommitTooltip                 string
+	NoBranchesFoundAtCommitTooltip        string
 	SureCheckoutThisCommit                string
 	GitFlowOptions                        string
 	NotAGitFlowBranch                     string
@@ -860,8 +861,11 @@ type Log struct {
 
 type Actions struct {
 	CheckoutCommit                    string
+	CheckoutBranchAtCommit            string
+	CheckoutCommitAsDetachedHead      string
 	CheckoutTag                       string
 	CheckoutBranch                    string
+	CheckoutBranchOrCommit            string
 	ForceCheckoutBranch               string
 	DeleteLocalBranch                 string
 	Merge                             string
@@ -1522,21 +1526,22 @@ func EnglishTranslationSet() *TranslationSet {
 		DeleteRemoteTagPrompt:                "Are you sure you want to delete the remote tag '{{.tagName}}' from '{{.upstream}}'?",
 		PushTagTitle:                         "Remote to push tag '{{.tagName}}' to:",
 		// Using 'push tag' rather than just 'push' to disambiguate from a global push
-		PushTag:                "Push tag",
+		PushTag:                        "Push tag",
-		PushTagTooltip:         "Push the selected tag to a remote. You'll be prompted to select a remote.",
+		PushTagTooltip:                 "Push the selected tag to a remote. You'll be prompted to select a remote.",
-		NewTag:                 "New tag",
+		NewTag:                         "New tag",
-		NewTagTooltip:          "Create new tag from current commit. You'll be prompted to enter a tag name and optional description.",
+		NewTagTooltip:                  "Create new tag from current commit. You'll be prompted to enter a tag name and optional description.",
-		CreatingTag:            "Creating tag",
+		CreatingTag:                    "Creating tag",
-		ForceTag:               "Force Tag",
+		ForceTag:                       "Force Tag",
-		ForceTagPrompt:         "The tag '{{.tagName}}' exists already. Press {{.cancelKey}} to cancel, or {{.confirmKey}} to overwrite.",
+		ForceTagPrompt:                 "The tag '{{.tagName}}' exists already. Press {{.cancelKey}} to cancel, or {{.confirmKey}} to overwrite.",
-		FetchRemoteTooltip:     "Fetch updates from the remote repository. This retrieves new commits and branches without merging them into your local branches.",
+		FetchRemoteTooltip:             "Fetch updates from the remote repository. This retrieves new commits and branches without merging them into your local branches.",
-		FetchingRemoteStatus:   "Fetching remote",
+		FetchingRemoteStatus:           "Fetching remote",
-		CheckoutCommit:         "Checkout commit",
+		CheckoutCommit:                 "Checkout commit",
-		CheckoutCommitTooltip:  "Checkout the selected commit as a detached HEAD.",
+		CheckoutCommitTooltip:          "Checkout the selected commit as a detached HEAD.",
-		SureCheckoutThisCommit: "Are you sure you want to checkout this commit?",
+		NoBranchesFoundAtCommitTooltip: "No branches found at selected commit.",
-		GitFlowOptions:         "Show git-flow options",
+		SureCheckoutThisCommit:         "Are you sure you want to checkout this commit?",
-		NotAGitFlowBranch:      "This does not seem to be a git flow branch",
+		GitFlowOptions:                 "Show git-flow options",
-		NewGitFlowBranchPrompt: "New {{.branchType}} name:",
+		NotAGitFlowBranch:              "This does not seem to be a git flow branch",
+		NewGitFlowBranchPrompt:         "New {{.branchType}} name:",
 
 		IgnoreTracked:                    "Ignore tracked file",
 		IgnoreTrackedPrompt:              "Are you sure you want to ignore a tracked file?",
@@ -1822,9 +1827,12 @@ func EnglishTranslationSet() *TranslationSet {
 		Actions: Actions{
 			// TODO: combine this with the original keybinding descriptions (those are all in lowercase atm)
 			CheckoutCommit:                 "Checkout commit",
+			CheckoutBranchAtCommit:         "Checkout branch '%s'",
+			CheckoutCommitAsDetachedHead:   "Checkout commit %s as detached head",
 			CheckoutTag:                    "Checkout tag",
 			CheckoutBranch:                 "Checkout branch",
 			ForceCheckoutBranch:            "Force checkout branch",
+			CheckoutBranchOrCommit:         "Checkout branch or commit",
 			DeleteLocalBranch:              "Delete local branch",
 			Merge:                          "Merge",
 			SquashMerge:                    "Squash merge",

pkg/integration/tests/commit/checkout.go

@@ -0,0 +1,69 @@
+package commit
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var Checkout = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Checkout a commit as a detached head, or checkout an existing branch at a commit",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo: func(shell *Shell) {
+		shell.EmptyCommit("one")
+		shell.EmptyCommit("two")
+		shell.NewBranch("branch1")
+		shell.NewBranch("branch2")
+		shell.EmptyCommit("three")
+		shell.EmptyCommit("four")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Commits().
+			Focus().
+			Lines(
+				Contains("four").IsSelected(),
+				Contains("three"),
+				Contains("two"),
+				Contains("one"),
+			).
+			PressPrimaryAction()
+
+		t.ExpectPopup().Menu().
+			Title(Contains("Checkout branch or commit")).
+			Lines(
+				Contains("Checkout branch").IsSelected(),
+				MatchesRegexp("Checkout commit [a-f0-9]+ as detached head"),
+				Contains("Cancel"),
+			).
+			Tooltip(Contains("Disabled: No branches found at selected commit.")).
+			Select(MatchesRegexp("Checkout commit [a-f0-9]+ as detached head")).
+			Confirm()
+		t.Views().Branches().Lines(
+			Contains("* (HEAD detached at"),
+			Contains("branch2"),
+			Contains("branch1"),
+			Contains("master"),
+		)
+
+		t.Views().Commits().
+			NavigateToLine(Contains("two")).
+			PressPrimaryAction()
+
+		t.ExpectPopup().Menu().
+			Title(Contains("Checkout branch or commit")).
+			Lines(
+				Contains("Checkout branch 'branch1'").IsSelected(),
+				Contains("Checkout branch 'master'"),
+				MatchesRegexp("Checkout commit [a-f0-9]+ as detached head"),
+				Contains("Cancel"),
+			).
+			Select(Contains("Checkout branch 'master'")).
+			Confirm()
+		t.Views().Branches().Lines(
+			Contains("master"),
+			Contains("branch2"),
+			Contains("branch1"),
+		)
+	},
+})

pkg/integration/tests/reflog/checkout.go

@@ -28,9 +28,9 @@ var Checkout = NewIntegrationTest(NewIntegrationTestArgs{
 			SelectNextItem().
 			PressPrimaryAction().
 			Tap(func() {
-				t.ExpectPopup().Confirmation().
+				t.ExpectPopup().Menu().
-					Title(Contains("Checkout commit")).
+					Title(Contains("Checkout branch or commit")).
-					Content(Contains("Are you sure you want to checkout this commit?")).
+					Select(MatchesRegexp("Checkout commit [a-f0-9]+ as detached head")).
 					Confirm()
 			}).
 			TopLines(

pkg/integration/tests/test_list.go

@@ -84,6 +84,7 @@ var tests = []*components.IntegrationTest{
 	commit.AddCoAuthorWhileCommitting,
 	commit.Amend,
 	commit.AutoWrapMessage,
+	commit.Checkout,
 	commit.Commit,
 	commit.CommitMultiline,
 	commit.CommitSwitchToEditor,