feat(pkg): support install refs in shorthand

Co-Authored-By: Virgil <virgil@lethean.io>

cmd/core/pkgcmd/cmd_install.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"strings"
 
@@ -22,10 +23,12 @@ var (
 	installAddToReg  bool
 )
 
+var errInvalidPkgInstallSource = errors.New("invalid repo format: use org/repo or org/repo@ref")
+
 // addPkgInstallCommand adds the 'pkg install' command.
 func addPkgInstallCommand(parent *cobra.Command) {
 	installCmd := &cobra.Command{
-		Use:   "install [org/]repo",
+		Use:   "install [org/]repo[@ref]",
 		Short: i18n.T("cmd.pkg.install.short"),
 		Long:  i18n.T("cmd.pkg.install.long"),
 		RunE: func(cmd *cobra.Command, args []string) error {
@@ -48,14 +51,9 @@ func runPkgInstall(repoArg, targetDir string, addToRegistry bool) error {
 	// Parse repo shorthand:
 	// - repoName -> defaults to host-uk/repoName
 	// - org/repo  -> uses the explicit org
-	org := "host-uk"
-	repoName := repoArg
-	if strings.Contains(repoArg, "/") {
-		parts := strings.Split(repoArg, "/")
-		if len(parts) != 2 || parts[0] == "" || parts[1] == "" {
-			return errors.New(i18n.T("cmd.pkg.error.invalid_repo_format"))
-		}
-		org, repoName = parts[0], parts[1]
+	org, repoName, ref, err := parsePkgInstallSource(repoArg)
+	if err != nil {
+		return err
 	}
 
 	// Determine target directory
@@ -93,11 +91,18 @@ func runPkgInstall(repoArg, targetDir string, addToRegistry bool) error {
 	}
 
 	fmt.Printf("%s %s/%s\n", dimStyle.Render(i18n.T("cmd.pkg.install.installing_label")), org, repoName)
+	if ref != "" {
+		fmt.Printf("%s %s\n", dimStyle.Render(i18n.Label("ref")), ref)
+	}
 	fmt.Printf("%s %s\n", dimStyle.Render(i18n.Label("target")), repoPath)
 	fmt.Println()
 
 	fmt.Printf("  %s... ", dimStyle.Render(i18n.T("common.status.cloning")))
-	err := gitClone(ctx, org, repoName, repoPath)
+	if ref == "" {
+		err = gitClone(ctx, org, repoName, repoPath)
+	} else {
+		err = gitCloneRef(ctx, org, repoName, repoPath, ref)
+	}
 	if err != nil {
 		fmt.Printf("%s\n", errorStyle.Render("✗ "+err.Error()))
 		return err
@@ -118,6 +123,36 @@ func runPkgInstall(repoArg, targetDir string, addToRegistry bool) error {
 	return nil
 }
 
+func parsePkgInstallSource(repoArg string) (org, repoName, ref string, err error) {
+	org = "host-uk"
+	repoName = strings.TrimSpace(repoArg)
+	if repoName == "" {
+		return "", "", "", errors.New("repository argument required")
+	}
+
+	if at := strings.LastIndex(repoName, "@"); at >= 0 {
+		ref = strings.TrimSpace(repoName[at+1:])
+		repoName = strings.TrimSpace(repoName[:at])
+		if ref == "" || repoName == "" {
+			return "", "", "", errInvalidPkgInstallSource
+		}
+	}
+
+	if strings.Contains(repoName, "/") {
+		parts := strings.Split(repoName, "/")
+		if len(parts) != 2 || parts[0] == "" || parts[1] == "" {
+			return "", "", "", errInvalidPkgInstallSource
+		}
+		org, repoName = parts[0], parts[1]
+	}
+
+	if strings.Contains(repoName, "/") {
+		return "", "", "", errInvalidPkgInstallSource
+	}
+
+	return org, repoName, ref, nil
+}
+
 func addToRegistryFile(org, repoName string) error {
 	regPath, err := repos.FindRegistry(coreio.Local)
 	if err != nil {
@@ -146,6 +181,30 @@ func addToRegistryFile(org, repoName string) error {
 	return coreio.Local.Write(regPath, content)
 }
 
+func clonePackageAtRef(ctx context.Context, org, repo, path, ref string) error {
+	if ghAuthenticated() {
+		httpsURL := fmt.Sprintf("https://github.com/%s/%s.git", org, repo)
+		args := []string{"repo", "clone", httpsURL, path, "--", "--branch", ref, "--single-branch"}
+		cmd := exec.CommandContext(ctx, "gh", args...)
+		output, err := cmd.CombinedOutput()
+		if err == nil {
+			return nil
+		}
+		errStr := strings.TrimSpace(string(output))
+		if strings.Contains(errStr, "already exists") {
+			return errors.New(errStr)
+		}
+	}
+
+	args := []string{"clone", "--branch", ref, "--single-branch", fmt.Sprintf("git@github.com:%s/%s.git", org, repo), path}
+	cmd := exec.CommandContext(ctx, "git", args...)
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		return errors.New(strings.TrimSpace(string(output)))
+	}
+	return nil
+}
+
 func detectRepoType(name string) string {
 	lower := strings.ToLower(name)
 	if strings.Contains(lower, "-mod-") || strings.HasSuffix(lower, "-mod") {

cmd/core/pkgcmd/cmd_install_test.go

@@ -67,3 +67,48 @@ func TestRunPkgInstall_InvalidRepoFormat_Bad(t *testing.T) {
 	require.Error(t, err)
 	assert.Contains(t, err.Error(), "invalid repo format")
 }
+
+func TestParsePkgInstallSource_Good(t *testing.T) {
+	t.Run("default org and repo", func(t *testing.T) {
+		org, repo, ref, err := parsePkgInstallSource("core-api")
+		require.NoError(t, err)
+		assert.Equal(t, "host-uk", org)
+		assert.Equal(t, "core-api", repo)
+		assert.Empty(t, ref)
+	})
+
+	t.Run("explicit org and ref", func(t *testing.T) {
+		org, repo, ref, err := parsePkgInstallSource("myorg/core-api@v1.2.3")
+		require.NoError(t, err)
+		assert.Equal(t, "myorg", org)
+		assert.Equal(t, "core-api", repo)
+		assert.Equal(t, "v1.2.3", ref)
+	})
+}
+
+func TestRunPkgInstall_WithRef_UsesRefClone_Good(t *testing.T) {
+	tmp := t.TempDir()
+	targetDir := filepath.Join(tmp, "packages")
+
+	originalGitCloneRef := gitCloneRef
+	t.Cleanup(func() {
+		gitCloneRef = originalGitCloneRef
+	})
+
+	var gotOrg, gotRepo, gotPath, gotRef string
+	gitCloneRef = func(_ context.Context, org, repoName, repoPath, ref string) error {
+		gotOrg = org
+		gotRepo = repoName
+		gotPath = repoPath
+		gotRef = ref
+		return nil
+	}
+
+	err := runPkgInstall("myorg/core-api@v1.2.3", targetDir, false)
+	require.NoError(t, err)
+
+	assert.Equal(t, "myorg", gotOrg)
+	assert.Equal(t, "core-api", gotRepo)
+	assert.Equal(t, filepath.Join(targetDir, "core-api"), gotPath)
+	assert.Equal(t, "v1.2.3", gotRef)
+}

cmd/core/pkgcmd/cmd_pkg.go

@@ -15,6 +15,7 @@ var (
 	dimStyle        = cli.DimStyle
 	ghAuthenticated = cli.GhAuthenticated
 	gitClone        = cli.GitClone
+	gitCloneRef     = clonePackageAtRef
 )
 
 // AddPkgCommands adds the 'pkg' command and subcommands for package management.

pkg/cli/utils.go

@@ -486,9 +486,19 @@ func ChooseMultiAction[T any](verb, subject string, items []T, opts ...ChooseOpt
 // GitClone clones a GitHub repository to the specified path.
 // Prefers 'gh repo clone' if authenticated, falls back to SSH.
 func GitClone(ctx context.Context, org, repo, path string) error {
+	return GitCloneRef(ctx, org, repo, path, "")
+}
+
+// GitCloneRef clones a GitHub repository at a specific ref to the specified path.
+// Prefers 'gh repo clone' if authenticated, falls back to SSH.
+func GitCloneRef(ctx context.Context, org, repo, path, ref string) error {
 	if GhAuthenticated() {
 		httpsURL := fmt.Sprintf("https://github.com/%s/%s.git", org, repo)
-		cmd := exec.CommandContext(ctx, "gh", "repo", "clone", httpsURL, path)
+		args := []string{"repo", "clone", httpsURL, path}
+		if ref != "" {
+			args = append(args, "--", "--branch", ref, "--single-branch")
+		}
+		cmd := exec.CommandContext(ctx, "gh", args...)
 		output, err := cmd.CombinedOutput()
 		if err == nil {
 			return nil
@@ -499,7 +509,12 @@ func GitClone(ctx context.Context, org, repo, path string) error {
 		}
 	}
 	// Fall back to SSH clone
-	cmd := exec.CommandContext(ctx, "git", "clone", fmt.Sprintf("git@github.com:%s/%s.git", org, repo), path)
+	args := []string{"clone"}
+	if ref != "" {
+		args = append(args, "--branch", ref, "--single-branch")
+	}
+	args = append(args, fmt.Sprintf("git@github.com:%s/%s.git", org, repo), path)
+	cmd := exec.CommandContext(ctx, "git", args...)
 	output, err := cmd.CombinedOutput()
 	if err != nil {
 		return errors.New(strings.TrimSpace(string(output)))