Support fastforwarding worktree

pkg/commands/git_commands/git_command_builder.go

@@ -1,6 +1,8 @@
 package git_commands
 
-import "strings"
+import (
+	"strings"
+)
 
 // convenience struct for building git commands. Especially useful when
 // including conditional args
@@ -66,6 +68,14 @@ func (self *GitCommandBuilder) GitDir(path string) *GitCommandBuilder {
 	return self
 }
 
+func (self *GitCommandBuilder) GitDirIf(condition bool, path string) *GitCommandBuilder {
+	if condition {
+		return self.GitDir(path)
+	}
+
+	return self
+}
+
 func (self *GitCommandBuilder) ToArgv() []string {
 	return append([]string{"git"}, self.args...)
 }

pkg/commands/git_commands/sync.go

@@ -82,6 +82,7 @@ type PullOptions struct {
 	RemoteName      string
 	BranchName      string
 	FastForwardOnly bool
+	WorktreeGitDir  string
 }
 
 func (self *SyncCommands) Pull(task gocui.Task, opts PullOptions) error {
@@ -90,6 +91,7 @@ func (self *SyncCommands) Pull(task gocui.Task, opts PullOptions) error {
 		ArgIf(opts.FastForwardOnly, "--ff-only").
 		ArgIf(opts.RemoteName != "", opts.RemoteName).
 		ArgIf(opts.BranchName != "", opts.BranchName).
+		GitDirIf(opts.WorktreeGitDir != "", opts.WorktreeGitDir).
 		ToArgv()
 
 	// setting GIT_SEQUENCE_EDITOR to ':' as a way of skipping it, in case the user
@@ -97,7 +99,12 @@ func (self *SyncCommands) Pull(task gocui.Task, opts PullOptions) error {
 	return self.cmd.New(cmdArgs).AddEnvVars("GIT_SEQUENCE_EDITOR=:").PromptOnCredentialRequest(task).WithMutex(self.syncMutex).Run()
 }
 
-func (self *SyncCommands) FastForward(task gocui.Task, branchName string, remoteName string, remoteBranchName string) error {
+func (self *SyncCommands) FastForward(
+	task gocui.Task,
+	branchName string,
+	remoteName string,
+	remoteBranchName string,
+) error {
 	cmdArgs := NewGitCmd("fetch").
 		Arg(remoteName).
 		Arg(remoteBranchName + ":" + branchName).

pkg/gui/controllers/branches_controller.go

@@ -3,6 +3,7 @@ package controllers
 import (
 	"errors"
 	"fmt"
+	"os"
 	"strings"
 
 	"github.com/jesseduffield/gocui"
@@ -426,15 +427,23 @@ func (self *BranchesController) fastForward(branch *models.Branch) error {
 	)
 
 	return self.c.WithLoaderPanel(message, func(task gocui.Task) error {
-		if branch == self.c.Helpers().Refs.GetCheckedOutRef() {
+		worktree, ok := self.worktreeForBranch(branch)
+		if ok {
 			self.c.LogAction(action)
 
+			worktreeGitDir := ""
+			// if it is the current worktree path, no need to specify the path
+			if !git_commands.IsCurrentWorktree(worktree.Path) {
+				worktreeGitDir = worktree.GitDir
+			}
+
 			err := self.c.Git().Sync.Pull(
 				task,
 				git_commands.PullOptions{
 					RemoteName:      branch.UpstreamRemote,
 					BranchName:      branch.UpstreamBranch,
 					FastForwardOnly: true,
+					WorktreeGitDir:  worktreeGitDir,
 				},
 			)
 			if err != nil {
@@ -444,7 +453,10 @@ func (self *BranchesController) fastForward(branch *models.Branch) error {
 			return self.c.Refresh(types.RefreshOptions{Mode: types.ASYNC})
 		} else {
 			self.c.LogAction(action)
-			err := self.c.Git().Sync.FastForward(task, branch.Name, branch.UpstreamRemote, branch.UpstreamBranch)
+
+			err := self.c.Git().Sync.FastForward(
+				task, branch.Name, branch.UpstreamRemote, branch.UpstreamBranch,
+			)
 			if err != nil {
 				_ = self.c.Error(err)
 			}
@@ -455,6 +467,20 @@ func (self *BranchesController) fastForward(branch *models.Branch) error {
 	})
 }
 
+func (self *BranchesController) worktreePathForBranch(branch *models.Branch) string {
+	worktreeForRef, ok := self.worktreeForBranch(branch)
+	if ok {
+		return worktreeForRef.Path
+	}
+
+	dir, err := os.Getwd()
+	if err != nil {
+		// swallow for now
+		return ""
+	}
+	return dir
+}
+
 func (self *BranchesController) createTag(branch *models.Branch) error {
 	return self.c.Helpers().Tags.OpenCreateTagPrompt(branch.FullRefName(), func() {})
 }

pkg/integration/components/shell.go

@@ -261,6 +261,13 @@ func (self *Shell) AddWorktree(base string, path string, newBranchName string) *
 	})
 }
 
+// add worktree and have it checkout the base branch
+func (self *Shell) AddWorktreeCheckout(base string, path string) *Shell {
+	return self.RunCommand([]string{
+		"git", "worktree", "add", path, base,
+	})
+}
+
 func (self *Shell) AddFileInWorktree(worktreePath string) *Shell {
 	self.CreateFile(filepath.Join(worktreePath, "content"), "content")
 

pkg/integration/tests/test_list.go

@@ -227,6 +227,7 @@ var tests = []*components.IntegrationTest{
 	worktree.Crud,
 	worktree.CustomCommand,
 	worktree.DetachWorktreeFromBranch,
+	worktree.FastForwardWorktreeBranch,
 	worktree.ForceRemoveWorktree,
 	worktree.Rebase,
 	worktree.RemoveWorktreeFromBranch,

pkg/integration/tests/worktree/fast_forward_worktree_branch.go

@@ -0,0 +1,52 @@
+package worktree
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var FastForwardWorktreeBranch = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Fast-forward a linked worktree branch from another worktree",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo: func(shell *Shell) {
+		// both main and linked worktree will have changed to fast-foward
+		shell.NewBranch("mybranch")
+		shell.CreateFileAndAdd("README.md", "hello world")
+		shell.Commit("initial commit")
+		shell.EmptyCommit("two")
+		shell.EmptyCommit("three")
+		shell.NewBranch("newbranch")
+
+		shell.CloneIntoRemote("origin")
+		shell.SetBranchUpstream("mybranch", "origin/mybranch")
+		shell.SetBranchUpstream("newbranch", "origin/newbranch")
+
+		// remove the 'three' commit so that we have something to pull from the remote
+		shell.HardReset("HEAD^")
+		shell.Checkout("mybranch")
+		shell.HardReset("HEAD^")
+
+		shell.AddWorktreeCheckout("newbranch", "../linked-worktree")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Branches().
+			Focus().
+			Lines(
+				Contains("mybranch").Contains("↓1").IsSelected(),
+				Contains("newbranch (worktree)").Contains("↓1"),
+			).
+			Press(keys.Branches.FastForward).
+			Lines(
+				Contains("mybranch").Contains("✓").IsSelected(),
+				Contains("newbranch (worktree)").Contains("↓1"),
+			).
+			NavigateToLine(Contains("newbranch (worktree)")).
+			Press(keys.Branches.FastForward).
+			Lines(
+				Contains("mybranch").Contains("✓"),
+				Contains("newbranch (worktree)").Contains("✓").IsSelected(),
+			)
+	},
+})