Demonstrate that the recent repos menu shows ".invalid" for a reftable repo

A repo that keeps its refs in a reftable shows ".invalid" in the branch
column. Git stores the real HEAD in a binary table there and leaves
"ref: refs/heads/.invalid" in the HEAD file, so that anything still
reading the HEAD file fails loudly instead of getting a stale answer.
We read that file and take the placeholder for a branch name.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

pkg/gui/controllers/helpers/repos_helper_test.go

@@ -66,6 +66,19 @@ func TestReadHeadInfo(t *testing.T) {
 			expected:   headInfo{branch: "mybranch"},
 			expectedOk: true,
 		},
+		{
+			name: "repo that keeps its refs in a reftable, so HEAD holds a placeholder",
+			files: map[string]string{
+				"repo/.git/HEAD": "ref: refs/heads/.invalid\n",
+			},
+			/* EXPECTED:
+			repoPath:   "repo",
+			expectedOk: false,
+			ACTUAL: */
+			repoPath:   "repo",
+			expected:   headInfo{branch: ".invalid"},
+			expectedOk: true,
+		},
 		{
 			name:       "directory without a .git entry",
 			repoPath:   "notarepo",

pkg/integration/tests/misc/recent_repos_reftable_repo.go

@@ -0,0 +1,40 @@
+package misc
+
+import (
+	"path/filepath"
+
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var RecentReposReftableRepo = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "The recent repositories menu shows the branch of a repo that keeps its refs in a reftable",
+	ExtraCmdArgs: []string{},
+	ExtraEnvVars: map[string]string{
+		"SHOW_RECENT_REPOS": "true",
+	},
+	Skip:       false,
+	GitVersion: AtLeast("2.45.0"),
+	SetupConfig: func(cfg *config.AppConfig) {
+		// the first entry is the repo we're in, so it isn't offered
+		current, _ := filepath.Abs(".")
+		reftable, _ := filepath.Abs("../reftable")
+		cfg.GetAppState().RecentRepos = []string{current, reftable}
+	},
+	SetupRepo: func(shell *Shell) {
+		shell.EmptyCommit("one")
+		shell.RunCommand([]string{"git", "clone", "--ref-format=reftable", ".", "../reftable"})
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.ExpectPopup().Menu().
+			Title(Equals("Recent repositories")).
+			Lines(
+				/* EXPECTED:
+				Contains("reftable").Contains("master").IsSelected(),
+				ACTUAL: */
+				Contains("reftable").Contains(".invalid").IsSelected(),
+				Contains("Cancel"),
+			).
+			Cancel()
+	},
+})

pkg/integration/tests/test_list.go

@@ -368,6 +368,7 @@ var tests = []*components.IntegrationTest{
 	misc.RecentReposBranchColumn,
 	misc.RecentReposColumnWidths,
 	misc.RecentReposOnLaunch,
+	misc.RecentReposReftableRepo,
 	misc.RecentReposWithLongNames,
 	misc.StartInGitDir,
 	patch_building.Apply,