Fix Windows path detection in GetHooksPath and add tests

- Use filepath.IsAbs() instead of Unix-only "/" prefix check
- Add test coverage for GetHooksPath with default, absolute, and
  relative core.hooksPath configurations

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: wesm

internal/git/git.go

@@ -230,7 +230,7 @@ func GetHooksPath(repoPath string) (string, error) {
 	hooksPath := strings.TrimSpace(string(out))
 
 	// If the path is relative, make it absolute relative to repoPath
-	if !strings.HasPrefix(hooksPath, "/") {
+	if !filepath.IsAbs(hooksPath) {
 		hooksPath = filepath.Join(repoPath, hooksPath)
 	}
 

internal/git/git_test.go

@@ -0,0 +1,98 @@
+package git
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestGetHooksPath(t *testing.T) {
+	// Create a temp git repo
+	tmpDir := t.TempDir()
+
+	cmd := exec.Command("git", "init")
+	cmd.Dir = tmpDir
+	if out, err := cmd.CombinedOutput(); err != nil {
+		t.Fatalf("git init failed: %v\n%s", err, out)
+	}
+
+	t.Run("default hooks path", func(t *testing.T) {
+		hooksPath, err := GetHooksPath(tmpDir)
+		if err != nil {
+			t.Fatalf("GetHooksPath failed: %v", err)
+		}
+
+		// Should be absolute
+		if !filepath.IsAbs(hooksPath) {
+			t.Errorf("hooks path should be absolute, got: %s", hooksPath)
+		}
+
+		// Should end with .git/hooks (or .git\hooks on Windows)
+		expectedSuffix := filepath.Join(".git", "hooks")
+		if !strings.HasSuffix(hooksPath, expectedSuffix) {
+			t.Errorf("hooks path should end with %s, got: %s", expectedSuffix, hooksPath)
+		}
+
+		// Should be under tmpDir
+		if !strings.HasPrefix(hooksPath, tmpDir) {
+			t.Errorf("hooks path should be under %s, got: %s", tmpDir, hooksPath)
+		}
+	})
+
+	t.Run("custom core.hooksPath absolute", func(t *testing.T) {
+		// Create a custom hooks directory
+		customHooksDir := filepath.Join(tmpDir, "my-hooks")
+		if err := os.MkdirAll(customHooksDir, 0755); err != nil {
+			t.Fatal(err)
+		}
+
+		// Set core.hooksPath to absolute path
+		cmd := exec.Command("git", "config", "core.hooksPath", customHooksDir)
+		cmd.Dir = tmpDir
+		if out, err := cmd.CombinedOutput(); err != nil {
+			t.Fatalf("git config failed: %v\n%s", err, out)
+		}
+
+		hooksPath, err := GetHooksPath(tmpDir)
+		if err != nil {
+			t.Fatalf("GetHooksPath failed: %v", err)
+		}
+
+		// Should return the custom absolute path
+		if hooksPath != customHooksDir {
+			t.Errorf("expected %s, got %s", customHooksDir, hooksPath)
+		}
+
+		// Reset for other tests
+		cmd = exec.Command("git", "config", "--unset", "core.hooksPath")
+		cmd.Dir = tmpDir
+		cmd.Run() // ignore error if not set
+	})
+
+	t.Run("custom core.hooksPath relative", func(t *testing.T) {
+		// Set core.hooksPath to relative path
+		cmd := exec.Command("git", "config", "core.hooksPath", "custom-hooks")
+		cmd.Dir = tmpDir
+		if out, err := cmd.CombinedOutput(); err != nil {
+			t.Fatalf("git config failed: %v\n%s", err, out)
+		}
+
+		hooksPath, err := GetHooksPath(tmpDir)
+		if err != nil {
+			t.Fatalf("GetHooksPath failed: %v", err)
+		}
+
+		// Should be made absolute
+		if !filepath.IsAbs(hooksPath) {
+			t.Errorf("hooks path should be absolute, got: %s", hooksPath)
+		}
+
+		// Should resolve to tmpDir/custom-hooks
+		expected := filepath.Join(tmpDir, "custom-hooks")
+		if hooksPath != expected {
+			t.Errorf("expected %s, got %s", expected, hooksPath)
+		}
+	})
+}