From 5d8937e22cbaf6e96d7fbd5811de33244b5d5c87 Mon Sep 17 00:00:00 2001
From: Paul Buetow <paul@buetow.org>
Date: Thu, 28 May 2026 09:40:56 +0300
Subject: fix(sync): correct local tag peel syntax in getTagCommitHash (kp)

---
 internal/sync/git_operations.go      | 15 ++++++--
 internal/sync/git_operations_test.go | 75 +++++++++++++++++++++++++++++++++++-
 2 files changed, 86 insertions(+), 4 deletions(-)

diff --git a/internal/sync/git_operations.go b/internal/sync/git_operations.go
index 6619349..08eea34 100644
--- a/internal/sync/git_operations.go
+++ b/internal/sync/git_operations.go
@@ -181,7 +181,7 @@ func handleTagConflict(repoPath, remote string, output []byte) error {
 func getTagCommitHash(repoPath, tag, source string) (string, error) {
 	var cmd *exec.Cmd
 	if source == "local" {
-		cmd = gitCommand(repoPath, "rev-parse", tag+"^{\\}")
+		cmd = gitCommand(repoPath, "rev-parse", tag+"^{}")
 	} else {
 		cmd = gitCommand(repoPath, "ls-remote", "--tags", source, tag)
 	}
@@ -191,8 +191,17 @@ func getTagCommitHash(repoPath, tag, source string) (string, error) {
 		return "", err
 	}
 
-	hash := strings.Fields(string(output))[0]
-	return hash, nil
+	return parseTagHashOutput(output, tag, source)
+}
+
+// parseTagHashOutput extracts the first whitespace-separated field from output
+// as the commit hash for a tag, returning an error when output is empty.
+func parseTagHashOutput(output []byte, tag, source string) (string, error) {
+	fields := strings.Fields(string(output))
+	if len(fields) == 0 {
+		return "", fmt.Errorf("no hash found for tag %s from %s", tag, source)
+	}
+	return fields[0], nil
 }
 
 // checkoutExistingBranch tries to checkout an existing branch
diff --git a/internal/sync/git_operations_test.go b/internal/sync/git_operations_test.go
index 03ddb81..e696fb7 100644
--- a/internal/sync/git_operations_test.go
+++ b/internal/sync/git_operations_test.go
@@ -1,6 +1,10 @@
 package sync
 
-import "testing"
+import (
+	"os/exec"
+	"strings"
+	"testing"
+)
 
 func TestGitCommand_SetsDir(t *testing.T) {
 	cmd := gitCommand("/tmp/example-repo", "status")
@@ -17,3 +21,72 @@ func TestGitCommand_LeavesDirEmptyForGlobalCommands(t *testing.T) {
 		t.Fatalf("expected empty dir for global command, got %q", cmd.Dir)
 	}
 }
+
+func TestParseTagHashOutput_EmptyOutput(t *testing.T) {
+	for _, in := range [][]byte{nil, []byte(""), []byte("   \n\t  \n")} {
+		hash, err := parseTagHashOutput(in, "v1.0.0", "origin")
+		if err == nil {
+			t.Fatalf("expected error for empty output %q, got hash %q", in, hash)
+		}
+		if hash != "" {
+			t.Fatalf("expected empty hash for empty output, got %q", hash)
+		}
+		if !strings.Contains(err.Error(), "v1.0.0") || !strings.Contains(err.Error(), "origin") {
+			t.Fatalf("expected error to mention tag and source, got %v", err)
+		}
+	}
+}
+
+func TestParseTagHashOutput_ReturnsFirstField(t *testing.T) {
+	hash, err := parseTagHashOutput([]byte("abc123\trefs/tags/v1.0.0\n"), "v1.0.0", "origin")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if hash != "abc123" {
+		t.Fatalf("expected hash %q, got %q", "abc123", hash)
+	}
+}
+
+func TestGetTagCommitHash_LocalTagPeelsToCommitHash(t *testing.T) {
+	repoPath := t.TempDir()
+
+	runGit(t, repoPath, "init")
+	runGit(t, repoPath, "-c", "user.name=Test", "-c", "user.email=test@example.com", "commit", "--allow-empty", "-m", "initial commit")
+	runGit(t, repoPath, "tag", "-a", "v1.0.0", "-m", "release v1.0.0")
+
+	headHash := runGit(t, repoPath, "rev-parse", "HEAD")
+	tagHash, err := getTagCommitHash(repoPath, "v1.0.0", "local")
+	if err != nil {
+		t.Fatalf("expected local tag hash lookup to succeed, got error: %v", err)
+	}
+	if tagHash != headHash {
+		t.Fatalf("expected peeled local tag hash %q, got %q", headHash, tagHash)
+	}
+}
+
+func TestGetTagCommitHash_LocalTagMissingReturnsError(t *testing.T) {
+	repoPath := t.TempDir()
+	runGit(t, repoPath, "init")
+
+	tagHash, err := getTagCommitHash(repoPath, "v9.9.9", "local")
+	if err == nil {
+		t.Fatalf("expected error for missing local tag, got hash %q", tagHash)
+	}
+	if tagHash != "" {
+		t.Fatalf("expected empty hash for missing local tag, got %q", tagHash)
+	}
+}
+
+func runGit(t *testing.T, repoPath string, args ...string) string {
+	t.Helper()
+
+	cmd := exec.Command("git", args...)
+	cmd.Dir = repoPath
+
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("git %v failed: %v\n%s", args, err, string(output))
+	}
+
+	return strings.TrimSpace(string(output))
+}
-- 
cgit v1.2.3