[fix] Check against origin/<mainBranch> in clean --merged (#31)

* fix: use origin/<mainBranch> after successful fetch in clean --merged

After git fetch updates remote-tracking refs, check merged status against
origin/<mainBranch> instead of local <mainBranch>. This correctly detects
branches merged via GitHub PRs, where local main is typically behind.

Falls back to local <mainBranch> when fetch fails (no remote).

* test: verify merge ref selection in clean --merged

- Rewrite TestCleanMergedFetchFails to assert local main is used as
  merge ref when fetch fails
- Add TestCleanMergedFetchSucceeds to assert origin/main is used when
  fetch succeeds
- Update findMergedCandidates calls for new two-param signature
- Remove unused fetchFailRunner helper

Author: lugassawan

cmd/clean.go

@@ -99,14 +99,17 @@ func cleanMerged(cmd *cobra.Command, r git.Runner) error {
 	defer s.Stop()
 
 	// Fetch latest (non-fatal)
+	mergeRef := mainBranch
 	s.Start("Fetching from origin...")
 	if err := git.Fetch(r, "origin"); err != nil {
 		s.Stop()
 		fmt.Fprintf(cmd.OutOrStdout(), "Warning: fetch failed (no remote?): continuing with local state\n")
+	} else {
+		mergeRef = "origin/" + mainBranch
 	}
 
 	s.Update("Analyzing branches...")
-	candidates, err := findMergedCandidates(r, mainBranch)
+	candidates, err := findMergedCandidates(r, mergeRef, mainBranch)
 	if err != nil {
 		return err
 	}
@@ -134,8 +137,8 @@ func cleanMerged(cmd *cobra.Command, r git.Runner) error {
 	return nil
 }
 
-func findMergedCandidates(r git.Runner, mainBranch string) ([]mergedCandidate, error) {
-	mergedList, err := git.MergedBranches(r, mainBranch)
+func findMergedCandidates(r git.Runner, mergeRef, mainBranch string) ([]mergedCandidate, error) {
+	mergedList, err := git.MergedBranches(r, mergeRef)
 	if err != nil {
 		return nil, fmt.Errorf("failed to list merged branches: %w", err)
 	}

cmd/clean_test.go

@@ -33,9 +33,9 @@ func TestFindMergedCandidatesFound(t *testing.T) {
 		"HEAD abc123",
 		"branch refs/heads/main",
 		"",
-		"worktree " + pathWtDone,
+		wtDone,
 		"HEAD def456",
-		"branch refs/heads/" + branchDone,
+		branchRefPrefix + branchDone,
 		"",
 		"worktree /wt/feature-active",
 		"HEAD ghi789",
@@ -44,9 +44,35 @@ func TestFindMergedCandidatesFound(t *testing.T) {
 	}, "\n")
 
 	r := mergedWorktreeRunner("  "+branchDone+"\n  bugfix/old", worktreeOut)
-	candidates, err := findMergedCandidates(r, branchMain)
+	candidates, err := findMergedCandidates(r, branchMain, branchMain)
 	if err != nil {
-		t.Fatalf("findMergedCandidates: %v", err)
+		t.Fatalf(fatalFindMerged, err)
+	}
+	if len(candidates) != 1 {
+		t.Fatalf("got %d candidates, want 1", len(candidates))
+	}
+	if candidates[0].branch != branchDone {
+		t.Errorf("branch = %q, want %q", candidates[0].branch, branchDone)
+	}
+}
+
+func TestFindMergedCandidatesRemoteRef(t *testing.T) {
+	worktreeOut := strings.Join([]string{
+		wtRepo,
+		headABC123,
+		branchRefMain,
+		"",
+		wtDone,
+		headDEF456,
+		branchRefPrefix + branchDone,
+		"",
+	}, "\n")
+
+	// mergeRef differs from mainBranch — simulates post-fetch scenario
+	r := mergedWorktreeRunner("  "+branchDone+"\n  main", worktreeOut)
+	candidates, err := findMergedCandidates(r, "origin/"+branchMain, branchMain)
+	if err != nil {
+		t.Fatalf(fatalFindMerged, err)
 	}
 	if len(candidates) != 1 {
 		t.Fatalf("got %d candidates, want 1", len(candidates))
@@ -58,9 +84,9 @@ func TestFindMergedCandidatesFound(t *testing.T) {
 
 func TestFindMergedCandidatesNone(t *testing.T) {
 	r := mergedWorktreeRunner("", wtRepo + headMainBlock)
-	candidates, err := findMergedCandidates(r, branchMain)
+	candidates, err := findMergedCandidates(r, branchMain, branchMain)
 	if err != nil {
-		t.Fatalf("findMergedCandidates: %v", err)
+		t.Fatalf(fatalFindMerged, err)
 	}
 	if len(candidates) != 0 {
 		t.Errorf("expected 0 candidates, got %d", len(candidates))
@@ -78,7 +104,7 @@ func TestFindMergedCandidatesError(t *testing.T) {
 		runInDir: noopRunInDir,
 	}
 
-	_, err := findMergedCandidates(r, branchMain)
+	_, err := findMergedCandidates(r, branchMain, branchMain)
 	if err == nil {
 		t.Fatal(errExpected)
 	}
@@ -98,50 +124,94 @@ func TestFindMergedCandidatesWorktreeError(t *testing.T) {
 		runInDir: noopRunInDir,
 	}
 
-	_, err := findMergedCandidates(r, branchMain)
+	_, err := findMergedCandidates(r, branchMain, branchMain)
 	if err == nil {
 		t.Fatal("expected error from ListWorktrees failure")
 	}
 }
 
-func fetchFailRunner(topLevel, worktreeOut string) *mockRunner {
-	return &mockRunner{
+func TestCleanMergedFetchFails(t *testing.T) {
+	worktreeOut := cleanMergedWorktreeOut()
+	cmd, buf := newCleanMergedCmd()
+	_ = cmd.Flags().Set(flagForce, "true")
+
+	var mergedRef string
+	r := &mockRunner{
 		run: func(args ...string) (string, error) {
 			if len(args) >= 2 && args[1] == cmdShowToplevel {
-				return topLevel, nil
+				return t.TempDir(), nil
 			}
 			if args[0] == cmdSymbolicRef {
 				return refsRemotesOriginMain, nil
 			}
-			if len(args) >= 1 && args[0] == "fetch" {
+			if args[0] == cmdFetch {
 				return "", errors.New("no remote")
 			}
-			if len(args) >= 1 && args[0] == cmdBranch {
+			if args[0] == cmdBranch {
+				mergedRef = args[len(args)-1]
 				return "", nil
 			}
-			if len(args) >= 1 && args[0] == cmdWorktreeTest {
+			if args[0] == cmdWorktreeTest {
 				return worktreeOut, nil
 			}
 			return "", nil
 		},
 		runInDir: noopRunInDir,
 	}
+
+	err := cleanMerged(cmd, r)
+	if err != nil {
+		t.Fatalf(fatalCleanMerged, err)
+	}
+	out := buf.String()
+	if !strings.Contains(out, "Warning: fetch failed") {
+		t.Errorf("expected fetch warning, got %q", out)
+	}
+	if mergedRef != branchMain {
+		t.Errorf("merged ref = %q, want %q (local fallback)", mergedRef, branchMain)
+	}
 }
 
-func TestCleanMergedFetchFails(t *testing.T) {
+func TestCleanMergedFetchSucceeds(t *testing.T) {
 	worktreeOut := cleanMergedWorktreeOut()
 	cmd, buf := newCleanMergedCmd()
 	_ = cmd.Flags().Set(flagForce, "true")
 
-	r := fetchFailRunner(t.TempDir(), worktreeOut)
+	var mergedRef string
+	r := &mockRunner{
+		run: func(args ...string) (string, error) {
+			if len(args) >= 2 && args[1] == cmdShowToplevel {
+				return t.TempDir(), nil
+			}
+			if args[0] == cmdSymbolicRef {
+				return refsRemotesOriginMain, nil
+			}
+			if args[0] == cmdFetch {
+				return "", nil // fetch succeeds
+			}
+			if args[0] == cmdBranch {
+				mergedRef = args[len(args)-1]
+				return "", nil
+			}
+			if args[0] == cmdWorktreeTest {
+				return worktreeOut, nil
+			}
+			return "", nil
+		},
+		runInDir: noopRunInDir,
+	}
 
 	err := cleanMerged(cmd, r)
 	if err != nil {
 		t.Fatalf(fatalCleanMerged, err)
 	}
 	out := buf.String()
-	if !strings.Contains(out, "Warning: fetch failed") {
-		t.Errorf("expected fetch warning, got %q", out)
+	if strings.Contains(out, "Warning: fetch failed") {
+		t.Errorf("unexpected fetch warning in output: %q", out)
+	}
+	wantRef := "origin/" + branchMain
+	if mergedRef != wantRef {
+		t.Errorf("merged ref = %q, want %q", mergedRef, wantRef)
 	}
 }
 
@@ -343,7 +413,7 @@ func cleanMergedTestRunner(t *testing.T, mergedOut, worktreeOut string) *mockRun
 			if len(args) >= 1 && args[0] == cmdWorktreeTest {
 				return worktreeOut, nil
 			}
-			if len(args) >= 1 && args[0] == "fetch" {
+			if len(args) >= 1 && args[0] == cmdFetch {
 				return "", errors.New("no remote")
 			}
 			return "", nil
@@ -366,9 +436,9 @@ func cleanMergedWorktreeOut() string {
 		"HEAD abc123",
 		"branch refs/heads/main",
 		"",
-		"worktree " + pathWtDone,
+		wtDone,
 		"HEAD def456",
-		"branch refs/heads/" + branchDone,
+		branchRefPrefix + branchDone,
 		"",
 	}, "\n")
 }

cmd/completions_test.go

@@ -15,7 +15,7 @@ func TestCompleteWorktreeTasks(t *testing.T) {
 		"",
 		wtFeatureLogin,
 		"HEAD def456",
-		"branch refs/heads/" + branchFeature,
+		branchRefPrefix + branchFeature,
 		"",
 		"worktree /wt/bugfix-typo",
 		"HEAD ghi789",
@@ -114,7 +114,7 @@ func TestCompleteWorktreeTasksSkipsBare(t *testing.T) {
 		"",
 		wtFeatureLogin,
 		"HEAD def456",
-		"branch refs/heads/" + branchFeature,
+		branchRefPrefix + branchFeature,
 		"",
 	}, "\n")
 

cmd/helpers_test.go

@@ -80,7 +80,7 @@ func TestListWorktreeInfos(t *testing.T) {
 		"",
 		"worktree /repo-worktrees/feature-login",
 		"HEAD def456",
-		"branch refs/heads/" + branchFeature,
+		branchRefPrefix + branchFeature,
 		"",
 	}, "\n")
 
@@ -122,7 +122,7 @@ func TestFindWorktree(t *testing.T) {
 		"",
 		"worktree /repo-worktrees/feature-login",
 		"HEAD def456",
-		"branch refs/heads/" + branchFeature,
+		branchRefPrefix + branchFeature,
 		"",
 	}, "\n")
 

cmd/mock_runner_test.go

@@ -34,11 +34,14 @@ const (
 	branchBugfixTypo      = "bugfix/typo"
 	msgRemovedWorktree    = "Removed worktree"
 
+	branchRefPrefix           = "branch refs/heads/"
+	wtDone                    = "worktree " + pathWtDone
 	wtFeatureLogin            = "worktree /wt/feature-login"
 	pathWorktreesFeatureLogin = "/worktrees/feature-login"
 	cmdRevList                = "rev-list"
 
 	// Shared git command and value constants
+	cmdFetch             = "fetch"
 	cmdRemove            = "remove"
 	cmdSymbolicRef       = "symbolic-ref"
 	cmdStatus            = "status"
@@ -53,7 +56,8 @@ const (
 	useTestCmd       = "test-cmd"
 
 	// Shared fatalf format strings
-	fatalMergeRunE = "mergeCmd.RunE: %v"
+	fatalFindMerged  = "findMergedCandidates: %v"
+	fatalMergeRunE   = "mergeCmd.RunE: %v"
 	fatalCleanPrune  = "cleanPrune: %v"
 	fatalCleanMerged = "cleanMerged: %v"
 	fatalListRunE    = "listCmd.RunE: %v"