feat(plugin): add --version flag to plugin update command

Add support for specifying a version constraint when updating plugins,
matching the existing behavior of helm plugin install.

Changes:
- Add --version flag to plugin update command
- Update VCSInstaller.Update() to resolve and checkout specified version
- Update FindSource() to accept version parameter
- Add TestVCSInstallerUpdateWithVersion test for version support

Signed-off-by: MrJack <36191829+biagiopietro@users.noreply.github.com>

internal/plugin/installer/installer.go

@@ -157,8 +157,8 @@ func NewForSource(source, version string) (installer Installer, err error) {
 }
 
 // FindSource determines the correct Installer for the given source.
-func FindSource(location string) (Installer, error) {
+func FindSource(location string, version string) (Installer, error) {
-	installer, err := existingVCSRepo(location)
+	installer, err := existingVCSRepo(location, version)
 	if err != nil && err.Error() == "Cannot detect VCS" {
 		slog.Warn(
 			"cannot get information about plugin source",

internal/plugin/installer/vcs_installer.go

@@ -38,14 +38,15 @@ type VCSInstaller struct {
 	base
 }
 
-func existingVCSRepo(location string) (Installer, error) {
+func existingVCSRepo(location string, version string) (Installer, error) {
 	repo, err := vcs.NewRepo("", location)
 	if err != nil {
 		return nil, err
 	}
 	i := &VCSInstaller{
-		Repo: repo,
+		Repo:    repo,
-		base: newBase(repo.Remote()),
+		Version: version,
+		base:    newBase(repo.Remote()),
 	}
 	return i, nil
 }
@@ -104,6 +105,17 @@ func (i *VCSInstaller) Update() error {
 	if err := i.Repo.Update(); err != nil {
 		return err
 	}
+
+	ref, err := i.solveVersion(i.Repo)
+	if err != nil {
+		return err
+	}
+	if ref != "" {
+		if err := i.setVersion(i.Repo, ref); err != nil {
+			return err
+		}
+	}
+
 	if !isPlugin(i.Repo.LocalPath()) {
 		return ErrMissingMetadata
 	}

internal/plugin/installer/vcs_installer_test.go

@@ -49,6 +49,7 @@ func (r *testRepo) UpdateVersion(version string) error {
 	r.current = version
 	return r.err
 }
+func (r *testRepo) IsDirty() bool { return false }
 
 func TestVCSInstaller(t *testing.T) {
 	ensure.HelmHome(t)
@@ -81,7 +82,7 @@ func TestVCSInstaller(t *testing.T) {
 	require.EqualErrorf(t, Install(i), "plugin already exists", "expected error for plugin exists")
 
 	// Testing FindSource method, expect error because plugin code is not a cloned repository
-	_, err = FindSource(i.Path())
+	_, err = FindSource(i.Path(), "")
 	require.Error(t, err, "expected error for inability to find plugin source, got none")
 	require.EqualErrorf(t, err, "cannot get information about plugin source", "expected error for inability to find plugin source")
 }
@@ -131,7 +132,7 @@ func TestVCSInstallerUpdate(t *testing.T) {
 	}
 
 	// Test FindSource method for positive result
-	pluginInfo, err := FindSource(i.Path())
+	pluginInfo, err := FindSource(i.Path(), "")
 	require.NoError(t, err)
 
 	vcsInstaller := pluginInfo.(*VCSInstaller)
@@ -147,3 +148,61 @@ func TestVCSInstallerUpdate(t *testing.T) {
 	// Testing update for error
 	require.EqualErrorf(t, Update(vcsInstaller), "plugin repo was modified", "expected error for plugin modified")
 }
+
+func TestVCSInstallerUpdateWithVersion(t *testing.T) {
+	ensure.HelmHome(t)
+
+	if err := os.MkdirAll(helmpath.DataPath("plugins"), 0755); err != nil {
+		t.Fatalf("Could not create %s: %s", helmpath.DataPath("plugins"), err)
+	}
+
+	source := "https://github.com/adamreese/helm-env"
+	testRepoPath, _ := filepath.Abs("../testdata/plugdir/good/echo-v1")
+	repo := &testRepo{
+		local:  testRepoPath,
+		remote: source,
+		tags:   []string{"0.1.0", "0.1.1", "0.2.0"},
+	}
+
+	// First install without version
+	i, err := NewForSource(source, "")
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	vcsInstaller, ok := i.(*VCSInstaller)
+	if !ok {
+		t.Fatal("expected a VCSInstaller")
+	}
+	vcsInstaller.Repo = repo
+
+	if err := Install(i); err != nil {
+		t.Fatal(err)
+	}
+
+	// Now test update with specific version constraint
+	vcsInstaller.Version = "~0.1.0"
+	if err := Update(vcsInstaller); err != nil {
+		t.Fatal(err)
+	}
+	if repo.current != "0.1.1" {
+		t.Fatalf("expected version '0.1.1', got %q", repo.current)
+	}
+
+	// Test update with different version constraint
+	vcsInstaller.Version = "0.2.0"
+	if err := Update(vcsInstaller); err != nil {
+		t.Fatal(err)
+	}
+	if repo.current != "0.2.0" {
+		t.Fatalf("expected version '0.2.0', got %q", repo.current)
+	}
+
+	// Test update with non-existent version
+	vcsInstaller.Version = "0.3.0"
+	if err := Update(vcsInstaller); err == nil {
+		t.Fatal("expected error for version does not exist, got none")
+	} else if err.Error() != fmt.Sprintf("requested version %q does not exist for plugin %q", "0.3.0", source) {
+		t.Fatalf("expected error for version does not exist, got (%v)", err)
+	}
+}

pkg/cmd/plugin_update.go

@@ -29,7 +29,8 @@ import (
 )
 
 type pluginUpdateOptions struct {
-	names []string
+	names   []string
+	version string
 }
 
 func newPluginUpdateCmd(out io.Writer) *cobra.Command {
@@ -49,6 +50,7 @@ func newPluginUpdateCmd(out io.Writer) *cobra.Command {
 			return o.run(out)
 		},
 	}
+	cmd.Flags().StringVar(&o.version, "version", "", "specify a version constraint. If this is not specified, the latest version is installed")
 	return cmd
 }
 
@@ -70,8 +72,8 @@ func (o *pluginUpdateOptions) run(out io.Writer) error {
 
 	for _, name := range o.names {
 		if found := findPlugin(plugins, name); found != nil {
-			if err := updatePlugin(found); err != nil {
+			if err := updatePlugin(found, o.version); err != nil {
-				errorPlugins = append(errorPlugins, fmt.Errorf("failed to update plugin %s, got error (%w)", name, err))
+				errorPlugins = append(errorPlugins, fmt.Errorf("failed to update plugin %s, got error (%v)", name, err))
 			} else {
 				fmt.Fprintf(out, "Updated plugin: %s\n", name)
 			}
@@ -85,7 +87,7 @@ func (o *pluginUpdateOptions) run(out io.Writer) error {
 	return nil
 }
 
-func updatePlugin(p plugin.Plugin) error {
+func updatePlugin(p plugin.Plugin, version string) error {
 	exactLocation, err := filepath.EvalSymlinks(p.Dir())
 	if err != nil {
 		return err
@@ -95,7 +97,7 @@ func updatePlugin(p plugin.Plugin) error {
 		return err
 	}
 
-	i, err := installer.FindSource(absExactLocation)
+	i, err := installer.FindSource(absExactLocation, version)
 	if err != nil {
 		return err
 	}