feat(gitlab): remove source branch on merge

.changes/unreleased/Changed-20250829-213725.yaml

@@ -0,0 +1,7 @@
+kind: Changed
+body: >-
+  gitlab:
+  Submit Merge Requests with `remove_source_branch=true`.
+  This will delete the source branch when the MR is merged.
+  Opt out of this behavior with the `spice.forge.gitlab.removeSourceBranch` option.
+time: 2025-08-29T21:37:25.235962-07:00

doc/includes/cli-reference.md

@@ -12,7 +12,7 @@ gs (git-spice) is a command line tool for stacking Git branches.
 * `-C`, `--dir=DIR`: Change to DIR before doing anything
 * `--[no-]prompt`: Whether to prompt for missing information
 
-**Configuration**: [spice.forge.github.apiUrl](/cli/config.md#spiceforgegithubapiurl), [spice.forge.github.url](/cli/config.md#spiceforgegithuburl), [spice.forge.gitlab.apiURL](/cli/config.md#spiceforgegitlabapiurl), [spice.forge.gitlab.oauth.clientID](/cli/config.md#spiceforgegitlaboauthclientid), [spice.forge.gitlab.url](/cli/config.md#spiceforgegitlaburl)
+**Configuration**: [spice.forge.github.apiUrl](/cli/config.md#spiceforgegithubapiurl), [spice.forge.github.url](/cli/config.md#spiceforgegithuburl), [spice.forge.gitlab.apiURL](/cli/config.md#spiceforgegitlabapiurl), [spice.forge.gitlab.oauth.clientID](/cli/config.md#spiceforgegitlaboauthclientid), [spice.forge.gitlab.removeSourceBranch](/cli/config.md#spiceforgegitlabremovesourcebranch), [spice.forge.gitlab.url](/cli/config.md#spiceforgegitlaburl)
 
 ## Shell
 

doc/src/cli/config.md

@@ -172,6 +172,17 @@ For Self-Hosted GitLab instances, you must set this value to a custom Client ID.
 
 See also [GitLab Self-Hosted](../setup/auth.md#gitlab-self-hosted).
 
+### spice.forge.gitlab.removeSourceBranch
+
+<!-- gs:unreleased -->
+
+Whether to remove the source branch when a Merge Request is merged.
+
+**Accepted values:**
+
+- `true` (default)
+- `false`
+
 ### spice.log.all
 
 Whether $$gs log short$$ and $$gs log long$$ should show all stacks by default,

internal/fixturetest/fixturetest.go

@@ -44,11 +44,10 @@ type TestingT interface {
 
 // Config configures the behavior of the fixture system.
 type Config struct {
-	// Update is a pointer to a value speciftying
-	// whether we're in update mode or read mode.
+	// Update reports whether we're in update more or read mode.
 	//
 	// This must not be nil.
-	Update *bool // required
+	Update func() bool // required
 }
 
 // Fixture is a value that is sourced from a function in update mode,
@@ -71,7 +70,7 @@ func (f Fixture[T]) Get(t TestingT) T {
 	t.Helper()
 
 	fpath := filepath.Join("testdata", t.Name(), f.name)
-	if *f.cfg.Update {
+	if f.cfg.Update() {
 		v := f.gen()
 
 		require.NoError(t, os.MkdirAll(filepath.Dir(fpath), 0o755))

internal/fixturetest/fixturetest_test.go

@@ -12,19 +12,21 @@ import (
 func TestFixture(t *testing.T) {
 	t.Chdir(t.TempDir())
 
-	cfg := fixturetest.Config{Update: new(bool)}
+	var giveUpdate bool
+
+	cfg := fixturetest.Config{Update: func() bool { return giveUpdate }}
 	fixture := fixturetest.New(cfg, "number", rand.Int)
 
 	// Initial generation.
-	*cfg.Update = true
+	giveUpdate = true
 	v1 := fixture.Get(t)
 
 	// Read from disk.
-	*cfg.Update = false
+	giveUpdate = false
 	assert.Equal(t, v1, fixture.Get(t))
 
 	// Update again.
-	*cfg.Update = true
+	giveUpdate = true
 	// At least one attempt out of N should succeed.
 	assert.EventuallyWithT(t, func(t *assert.CollectT) {
 		v2 := fixture.Get(collectTAdapter{t, "Update"})

internal/forge/github/flag_test.go

@@ -2,13 +2,12 @@ package github
 
 import "flag"
 
-var UpdateFixtures *bool
+func UpdateFixtures() bool {
+	return flag.Lookup("update").Value.(flag.Getter).Get().(bool)
+}
 
 func init() {
-	if updateFlag := flag.Lookup("update"); updateFlag != nil {
-		value := updateFlag.Value.(flag.Getter).Get().(bool)
-		UpdateFixtures = &value
-	} else {
-		UpdateFixtures = flag.Bool("update", false, "update test fixtures")
+	if flag.Lookup("update") == nil {
+		flag.Bool("update", false, "update test fixtures")
 	}
 }

internal/forge/github/integration_test.go

@@ -31,10 +31,7 @@ import (
 // This file tests basic, end-to-end interactions with the GitHub API
 // using recorded fixtures.
 
-var (
-	_update   = github.UpdateFixtures
-	_fixtures = fixturetest.Config{Update: _update}
-)
+var _fixtures = fixturetest.Config{Update: github.UpdateFixtures}
 
 // To avoid looking this up for every test that needs the repo ID,
 // we'll just hardcode it here.
@@ -52,7 +49,7 @@ func newRecorder(t *testing.T, name string) *recorder.Recorder {
 	})
 
 	return httptest.NewTransportRecorder(t, name, httptest.TransportRecorderOptions{
-		Update: _update,
+		Update: github.UpdateFixtures,
 		WrapRealTransport: func(t testing.TB, transport http.RoundTripper) http.RoundTripper {
 			githubToken := os.Getenv("GITHUB_TOKEN")
 			require.NotEmpty(t, githubToken,
@@ -247,7 +244,7 @@ func TestIntegration_Repository_SubmitEditChange(t *testing.T) {
 		gitRepo *git.Repository // only when _update is true
 		gitWork *git.Worktree
 	)
-	if *_update {
+	if github.UpdateFixtures() {
 		t.Setenv("GIT_AUTHOR_EMAIL", "bot@example.com")
 		t.Setenv("GIT_AUTHOR_NAME", "gs-test[bot]")
 		t.Setenv("GIT_COMMITTER_EMAIL", "bot@example.com")
@@ -331,7 +328,7 @@ func TestIntegration_Repository_SubmitEditChange(t *testing.T) {
 
 		newBase := newBaseFixture.Get(t)
 		t.Logf("Pushing new base: %s", newBase)
-		if *_update {
+		if github.UpdateFixtures() {
 			require.NoError(t,
 				gitWork.Push(t.Context(), git.PushOptions{
 					Remote:  "origin",
@@ -409,7 +406,7 @@ func TestIntegration_Repository_SubmitEditChange_labels(t *testing.T) {
 		gitRepo *git.Repository // only when _update is true
 		gitWork *git.Worktree
 	)
-	if *_update {
+	if github.UpdateFixtures() {
 		t.Setenv("GIT_AUTHOR_EMAIL", "bot@example.com")
 		t.Setenv("GIT_AUTHOR_NAME", "gs-test[bot]")
 		t.Setenv("GIT_COMMITTER_EMAIL", "bot@example.com")
@@ -566,7 +563,7 @@ func TestIntegration_Repository_SubmitChange_baseBranchDoesNotExist(t *testing.T
 		gitRepo *git.Repository // only when _update is true
 		gitWork *git.Worktree
 	)
-	if *_update {
+	if github.UpdateFixtures() {
 		t.Setenv("GIT_AUTHOR_EMAIL", "bot@example.com")
 		t.Setenv("GIT_AUTHOR_NAME", "gs-test[bot]")
 		t.Setenv("GIT_COMMITTER_EMAIL", "bot@example.com")

internal/forge/gitlab/comment_test.go

@@ -162,7 +162,7 @@ func TestListChangeComments(t *testing.T) {
 				"owner", "repo",
 				silogtest.New(t),
 				client,
-				&repoID,
+				&repositoryOptions{RepositoryID: &repoID},
 			)
 			require.NoError(t, err)
 

internal/forge/gitlab/flag_test.go

@@ -2,13 +2,12 @@ package gitlab
 
 import "flag"
 
-var UpdateFixtures *bool
+func UpdateFixtures() bool {
+	return flag.Lookup("update").Value.(flag.Getter).Get().(bool)
+}
 
 func init() {
-	if updateFlag := flag.Lookup("update"); updateFlag != nil {
-		value := updateFlag.Value.(flag.Getter).Get().(bool)
-		UpdateFixtures = &value
-	} else {
-		UpdateFixtures = flag.Bool("update", false, "update test fixtures")
+	if flag.Lookup("update") == nil {
+		flag.Bool("update", false, "update test fixtures")
 	}
 }

internal/forge/gitlab/forge.go

@@ -38,6 +38,10 @@ type Options struct {
 	// ClientID is the OAuth client ID for GitLab OAuth device flow.
 	// This should be used if the GitLab instance is Self Managed.
 	ClientID string `name:"gitlab-oauth-client-id" hidden:"" env:"GITLAB_OAUTH_CLIENT_ID" config:"forge.gitlab.oauth.clientID" help:"GitLab OAuth client ID"`
+
+	// RemoveSourceBranch specifies whether a branch should be deleted
+	// after its Merge Request is merged.
+	RemoveSourceBranch bool `name:"gitlab-remove-source-branch" hidden:"" config:"forge.gitlab.removeSourceBranch" default:"true" help:"Remove source branch after merging a merge request"`
 }
 
 // Forge builds a GitLab Forge.
@@ -101,7 +105,9 @@ func (f *Forge) OpenRepository(ctx context.Context, token forge.AuthenticationTo
 		return nil, fmt.Errorf("create GitLab client: %w", err)
 	}
 
-	return newRepository(ctx, f, rid.owner, rid.name, f.logger(), glc, nil)
+	return newRepository(ctx, f, rid.owner, rid.name, f.logger(), glc, &repositoryOptions{
+		RemoveSourceBranchOnMerge: f.Options.RemoveSourceBranch,
+	})
 }
 
 // RepositoryID is a unique identifier for a GitLab repository.