From 6f9e18a1cec6543160a2ad54bdee06c3efff7297 Mon Sep 17 00:00:00 2001
From: Jonatan Dahl <jd@spotify.com>
Date: Wed, 28 Jan 2026 19:19:17 -0500
Subject: [PATCH 1/2] feat: fast-forward main when no stack branches

---
 cmd/sync.go                | 10 ++++++++++
 cmd/sync_test.go           |  1 +
 internal/git/git.go        | 11 +++++++++++
 internal/git/interface.go  |  1 +
 internal/testutil/mocks.go |  5 +++++
 5 files changed, 28 insertions(+)

diff --git a/cmd/sync.go b/cmd/sync.go
index f2ba742..c02971d 100644
--- a/cmd/sync.go
+++ b/cmd/sync.go
@@ -314,7 +314,17 @@ func runSync(gitClient git.GitClient, githubClient github.GitHubClient) error {
 	if len(chain) == 0 {
 		// Wait for parallel operations before returning
 		wg.Wait()
+		if fetchErr != nil {
+			return fmt.Errorf("failed to fetch: %w", fetchErr)
+		}
 		fmt.Println("No stack branches found.")
+		if originalBranch == baseBranch {
+			fmt.Printf("Updating %s from origin...\n", ui.Branch(baseBranch))
+			if err := gitClient.FastForwardToRemote(baseBranch); err != nil {
+				return fmt.Errorf("failed to update %s: %w", baseBranch, err)
+			}
+			fmt.Println(ui.Success(fmt.Sprintf("Updated %s", ui.Branch(baseBranch))))
+		}
 		return nil
 	}
 
diff --git a/cmd/sync_test.go b/cmd/sync_test.go
index 906fcc0..96735ec 100644
--- a/cmd/sync_test.go
+++ b/cmd/sync_test.go
@@ -494,6 +494,7 @@ func TestRunSyncNoStackBranches(t *testing.T) {
 	// These are started but may not complete before early return
 	mockGit.On("Fetch").Return(nil).Maybe()
 	mockGH.On("GetAllPRs").Return(make(map[string]*github.PRInfo), nil).Maybe()
+	mockGit.On("FastForwardToRemote", "main").Return(nil).Maybe()
 
 	// These calls don't happen when there are no stack branches (early return)
 
diff --git a/internal/git/git.go b/internal/git/git.go
index a3699f9..9e537ed 100644
--- a/internal/git/git.go
+++ b/internal/git/git.go
@@ -273,6 +273,17 @@ func (c *gitClient) Fetch() error {
 	return err
 }
 
+// FastForwardToRemote fast-forwards the current branch to match origin/<branch>
+func (c *gitClient) FastForwardToRemote(branch string) error {
+	remoteBranch := "origin/" + branch
+	if DryRun {
+		fmt.Printf("  [DRY RUN] git merge --ff-only %s\n", remoteBranch)
+		return nil
+	}
+	_, err := c.runCmd("merge", "--ff-only", remoteBranch)
+	return err
+}
+
 // BranchExists checks if a branch exists locally
 func (c *gitClient) BranchExists(name string) bool {
 	output := c.runCmdMayFail("rev-parse", "--verify", "refs/heads/"+name)
diff --git a/internal/git/interface.go b/internal/git/interface.go
index fb36b95..6fdafde 100644
--- a/internal/git/interface.go
+++ b/internal/git/interface.go
@@ -21,6 +21,7 @@ type GitClient interface {
 	ForcePush(branch string) error
 	IsWorkingTreeClean() (bool, error)
 	Fetch() error
+	FastForwardToRemote(branch string) error
 	BranchExists(name string) bool
 	RemoteBranchExists(name string) bool
 	GetRemoteBranchesSet() map[string]bool
diff --git a/internal/testutil/mocks.go b/internal/testutil/mocks.go
index fe28f3a..2938279 100644
--- a/internal/testutil/mocks.go
+++ b/internal/testutil/mocks.go
@@ -105,6 +105,11 @@ func (m *MockGitClient) Fetch() error {
 	return args.Error(0)
 }
 
+func (m *MockGitClient) FastForwardToRemote(branch string) error {
+	args := m.Called(branch)
+	return args.Error(0)
+}
+
 func (m *MockGitClient) BranchExists(name string) bool {
 	args := m.Called(name)
 	return args.Bool(0)

From 078a36987d79670c3c9abdf40a7b4bf3d18aa44f Mon Sep 17 00:00:00 2001
From: Jonatan Dahl <jd@spotify.com>
Date: Wed, 28 Jan 2026 19:23:21 -0500
Subject: [PATCH 2/2] fix: clarify status message when on base branch

---
 cmd/status.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmd/status.go b/cmd/status.go
index 5ec91d1..ddf791c 100644
--- a/cmd/status.go
+++ b/cmd/status.go
@@ -185,7 +185,7 @@ func runStatus(gitClient git.GitClient, githubClient github.GitHubClient) error
 
 		// Don't offer to add the base branch to a stack - it can't have a parent
 		if currentBranch == baseBranch {
-			fmt.Printf("Branch '%s' is the base branch and cannot be part of a stack.\n", ui.Branch(currentBranch))
+			fmt.Printf("No stack found. You're on the base branch (%s).\n", ui.Branch(currentBranch))
 			fmt.Printf("\nUse '%s' to create a new stack branch.\n", ui.Command("stack new <branch-name>"))
 			return nil
 		}