Let the caller of buildAheadBehindForEachRefArgs choose the refs

The function always asked about every ref under refs/heads. Sorting refs
by ancestry needs the ahead-behind values of a handful of named refs, and
for remote branches those live under refs/remotes, so take the patterns
as an argument. The bases can be commit hashes as well as ref names.

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

pkg/commands/git_commands/ahead_behind.go

@@ -74,23 +74,25 @@ func selectBehindForBranch(aheadBehinds []aheadBehind) int {
 	}).behind
 }
 
-// The output format is:
+// Builds a for-each-ref command that reports, for each ref matched by one of
+// refPatterns, how far it is ahead and behind each of the bases. A base is a
+// ref name or a commit hash. The output format is:
 //
 //	<refname>\x00<ahead> <behind>\x00<ahead> <behind>...\n
 //
-// with one ahead-behind field per base, in the same order as mainBranchRefs.
+// with one ahead-behind field per base, in the same order as bases.
 //
 // Requires git >= 2.41 (when %(ahead-behind:...) was added).
-func buildAheadBehindForEachRefArgs(mainBranchRefs []string) []string {
-	formatParts := make([]string, 0, 1+len(mainBranchRefs))
+func buildAheadBehindForEachRefArgs(bases []string, refPatterns []string) []string {
+	formatParts := make([]string, 0, 1+len(bases))
 	formatParts = append(formatParts, "%(refname)")
-	for _, ref := range mainBranchRefs {
-		formatParts = append(formatParts, "%(ahead-behind:"+ref+")")
+	for _, base := range bases {
+		formatParts = append(formatParts, "%(ahead-behind:"+base+")")
 	}
 	format := strings.Join(formatParts, "%00")
 
 	return NewGitCmd("for-each-ref").
 		Arg("--format=" + format).
-		Arg("refs/heads").
+		Arg(refPatterns...).
 		ToArgv()
 }

pkg/commands/git_commands/ahead_behind_test.go

@@ -197,15 +197,17 @@ func TestSelectBehindForBranch(t *testing.T) {
 
 func TestBuildAheadBehindForEachRefArgs(t *testing.T) {
 	type scenario struct {
-		testName       string
-		mainBranchRefs []string
-		expected       []string
+		testName    string
+		bases       []string
+		refPatterns []string
+		expected    []string
 	}
 
 	scenarios := []scenario{
 		{
-			testName:       "single base",
-			mainBranchRefs: []string{"refs/heads/master"},
+			testName:    "single base",
+			bases:       []string{"refs/heads/master"},
+			refPatterns: []string{"refs/heads"},
 			expected: []string{
 				"git",
 				"for-each-ref",
@@ -214,8 +216,9 @@ func TestBuildAheadBehindForEachRefArgs(t *testing.T) {
 			},
 		},
 		{
-			testName:       "two bases",
-			mainBranchRefs: []string{"refs/heads/master", "refs/remotes/origin/develop"},
+			testName:    "two bases",
+			bases:       []string{"refs/heads/master", "refs/remotes/origin/develop"},
+			refPatterns: []string{"refs/heads"},
 			expected: []string{
 				"git",
 				"for-each-ref",
@@ -224,8 +227,9 @@ func TestBuildAheadBehindForEachRefArgs(t *testing.T) {
 			},
 		},
 		{
-			testName:       "four bases",
-			mainBranchRefs: []string{"refs/heads/a", "refs/heads/b", "refs/heads/c", "refs/heads/d"},
+			testName:    "four bases",
+			bases:       []string{"refs/heads/a", "refs/heads/b", "refs/heads/c", "refs/heads/d"},
+			refPatterns: []string{"refs/heads"},
 			expected: []string{
 				"git",
 				"for-each-ref",
@@ -233,11 +237,23 @@ func TestBuildAheadBehindForEachRefArgs(t *testing.T) {
 				"refs/heads",
 			},
 		},
+		{
+			testName:    "commit hashes as bases, individual refs as patterns",
+			bases:       []string{"1234567", "89abcde"},
+			refPatterns: []string{"refs/heads/a", "refs/remotes/origin/b"},
+			expected: []string{
+				"git",
+				"for-each-ref",
+				"--format=%(refname)%00%(ahead-behind:1234567)%00%(ahead-behind:89abcde)",
+				"refs/heads/a",
+				"refs/remotes/origin/b",
+			},
+		},
 	}
 
 	for _, s := range scenarios {
 		t.Run(s.testName, func(t *testing.T) {
-			result := buildAheadBehindForEachRefArgs(s.mainBranchRefs)
+			result := buildAheadBehindForEachRefArgs(s.bases, s.refPatterns)
 			assert.Equal(t, s.expected, result)
 		})
 	}

pkg/commands/git_commands/branch_loader.go

@@ -214,7 +214,7 @@ func (self *BranchLoader) getBehindBaseBranchValuesFast(
 	t := time.Now()
 
 	output, err := self.cmd.New(
-		buildAheadBehindForEachRefArgs(mainBranchRefs),
+		buildAheadBehindForEachRefArgs(mainBranchRefs, []string{"refs/heads"}),
 	).DontLog().RunWithOutput()
 	if err != nil {
 		return err