Add command "Rebase onto base branch" to rebase menu

pkg/gui/controllers/helpers/merge_and_rebase_helper.go

@@ -234,11 +234,22 @@ func (self *MergeAndRebaseHelper) PromptToContinueRebase() error {
 }
 
 func (self *MergeAndRebaseHelper) RebaseOntoRef(ref string) error {
-	checkedOutBranch := self.refsHelper.GetCheckedOutRef().Name
-	var disabledReason *types.DisabledReason
-	if checkedOutBranch == ref {
+	checkedOutBranch := self.refsHelper.GetCheckedOutRef()
+	checkedOutBranchName := self.refsHelper.GetCheckedOutRef().Name
+	var disabledReason, baseBranchDisabledReason *types.DisabledReason
+	if checkedOutBranchName == ref {
 		disabledReason = &types.DisabledReason{Text: self.c.Tr.CantRebaseOntoSelf}
 	}
+
+	baseBranch, err := self.c.Git().Loaders.BranchLoader.GetBaseBranch(checkedOutBranch, self.refsHelper.c.Model().MainBranches)
+	if err != nil {
+		return err
+	}
+	if baseBranch == "" {
+		baseBranch = self.c.Tr.CouldNotDetermineBaseBranch
+		baseBranchDisabledReason = &types.DisabledReason{Text: self.c.Tr.CouldNotDetermineBaseBranch}
+	}
+
 	menuItems := []*types.MenuItem{
 		{
 			Label: utils.ResolvePlaceholderString(self.c.Tr.SimpleRebase,
@@ -289,6 +300,31 @@ func (self *MergeAndRebaseHelper) RebaseOntoRef(ref string) error {
 				return self.c.PushContext(self.c.Contexts().LocalCommits)
 			},
 		},
+		{
+			Label: utils.ResolvePlaceholderString(self.c.Tr.RebaseOntoBaseBranch,
+				map[string]string{"baseBranch": ShortBranchName(baseBranch)},
+			),
+			Key:            'b',
+			DisabledReason: baseBranchDisabledReason,
+			Tooltip:        self.c.Tr.RebaseOntoBaseBranchTooltip,
+			OnPress: func() error {
+				self.c.LogAction(self.c.Tr.Actions.RebaseBranch)
+				return self.c.WithWaitingStatus(self.c.Tr.RebasingStatus, func(task gocui.Task) error {
+					baseCommit := self.c.Modes().MarkedBaseCommit.GetHash()
+					var err error
+					if baseCommit != "" {
+						err = self.c.Git().Rebase.RebaseBranchFromBaseCommit(baseBranch, baseCommit)
+					} else {
+						err = self.c.Git().Rebase.RebaseBranch(baseBranch)
+					}
+					err = self.CheckMergeOrRebase(err)
+					if err == nil {
+						return self.ResetMarkedBaseCommit()
+					}
+					return err
+				})
+			},
+		},
 	}
 
 	title := utils.ResolvePlaceholderString(
@@ -296,7 +332,7 @@ func (self *MergeAndRebaseHelper) RebaseOntoRef(ref string) error {
 			self.c.Tr.RebasingFromBaseCommitTitle,
 			self.c.Tr.RebasingTitle),
 		map[string]string{
-			"checkedOutBranch": checkedOutBranch,
+			"checkedOutBranch": checkedOutBranchName,
 		},
 	)
 

pkg/i18n/english.go

@@ -289,7 +289,9 @@ type TranslationSet struct {
 	RebasingFromBaseCommitTitle           string
 	SimpleRebase                          string
 	InteractiveRebase                     string
+	RebaseOntoBaseBranch                  string
 	InteractiveRebaseTooltip              string
+	RebaseOntoBaseBranchTooltip           string
 	MustSelectTodoCommits                 string
 	ConfirmMerge                          string
 	FwdNoUpstream                         string
@@ -1257,7 +1259,9 @@ func EnglishTranslationSet() TranslationSet {
 		RebasingFromBaseCommitTitle:          "Rebase '{{.checkedOutBranch}}' from marked base",
 		SimpleRebase:                         "Simple rebase onto '{{.ref}}'",
 		InteractiveRebase:                    "Interactive rebase onto '{{.ref}}'",
+		RebaseOntoBaseBranch:                 "Rebase onto base branch ({{.baseBranch}})",
 		InteractiveRebaseTooltip:             "Begin an interactive rebase with a break at the start, so you can update the TODO commits before continuing.",
+		RebaseOntoBaseBranchTooltip:          "Rebase the checked out branch onto its base branch (i.e. the closest main branch).",
 		MustSelectTodoCommits:                "When rebasing, this action only works on a selection of TODO commits.",
 		ConfirmMerge:                         "Are you sure you want to merge '{{.selectedBranch}}' into '{{.checkedOutBranch}}'?",
 		FwdNoUpstream:                        "Cannot fast-forward a branch with no upstream",

pkg/integration/tests/branch/rebase_onto_base_branch.go

@@ -0,0 +1,53 @@
+package branch
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var RebaseOntoBaseBranch = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Rebase the current branch onto its base branch",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+		config.UserConfig.Gui.ShowDivergenceFromBaseBranch = "arrowAndNumber"
+	},
+	SetupRepo: func(shell *Shell) {
+		shell.
+			EmptyCommit("master 1").
+			EmptyCommit("master 2").
+			EmptyCommit("master 3").
+			NewBranchFrom("feature", "master^").
+			EmptyCommit("feature 1").
+			EmptyCommit("feature 2")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Commits().Lines(
+			Contains("feature 2"),
+			Contains("feature 1"),
+			Contains("master 2"),
+			Contains("master 1"),
+		)
+
+		t.Views().Branches().
+			Focus().
+			Lines(
+				Contains("feature ↓1").IsSelected(),
+				Contains("master"),
+			).
+			Press(keys.Branches.RebaseBranch)
+
+		t.ExpectPopup().Menu().
+			Title(Equals("Rebase 'feature'")).
+			Select(Contains("Rebase onto base branch (master)")).
+			Confirm()
+
+		t.Views().Commits().Lines(
+			Contains("feature 2"),
+			Contains("feature 1"),
+			Contains("master 3"),
+			Contains("master 2"),
+			Contains("master 1"),
+		)
+	},
+})

pkg/integration/tests/test_list.go

@@ -51,6 +51,7 @@ var tests = []*components.IntegrationTest{
 	branch.RebaseCopiedBranch,
 	branch.RebaseDoesNotAutosquash,
 	branch.RebaseFromMarkedBase,
+	branch.RebaseOntoBaseBranch,
 	branch.RebaseToUpstream,
 	branch.Rename,
 	branch.Reset,