New registry plugin func GetPluginName. Re-use regsitry.reference

Signed-off-by: Scott Rigby <scott@r6by.com>

internal/plugin/installer/oci_installer.go

@@ -24,7 +24,6 @@ import (
 	"log/slog"
 	"os"
 	"path/filepath"
-	"strings"
 
 	"helm.sh/helm/v4/internal/plugin/cache"
 	"helm.sh/helm/v4/internal/third_party/dep/fs"
@@ -45,21 +44,10 @@ type OCIInstaller struct {
 
 // NewOCIInstaller creates a new OCIInstaller with optional getter options
 func NewOCIInstaller(source string, options ...getter.Option) (*OCIInstaller, error) {
-	ref := strings.TrimPrefix(source, fmt.Sprintf("%s://", registry.OCIScheme))
-
-	// Extract plugin name from OCI reference
-	// e.g., "ghcr.io/user/plugin-name:v1.0.0" -> "plugin-name"
-	parts := strings.Split(ref, "/")
-	if len(parts) < 2 {
-		return nil, fmt.Errorf("invalid OCI reference: %s", source)
-	}
-	lastPart := parts[len(parts)-1]
-	pluginName := lastPart
-	if idx := strings.LastIndex(lastPart, ":"); idx > 0 {
-		pluginName = lastPart[:idx]
-	}
-	if idx := strings.LastIndex(lastPart, "@"); idx > 0 {
-		pluginName = lastPart[:idx]
+	// Extract plugin name from OCI reference using robust registry parsing
+	pluginName, err := registry.GetPluginName(source)
+	if err != nil {
+		return nil, err
 	}
 
 	key, err := cache.Key(source)

pkg/registry/plugin.go

@@ -174,3 +174,28 @@ func PluginPullOptWithPluginName(name string) PluginPullOption {
 		operation.pluginName = name
 	}
 }
+
+// GetPluginName extracts the plugin name from an OCI reference using proper reference parsing
+func GetPluginName(source string) (string, error) {
+	ref, err := newReference(source)
+	if err != nil {
+		return "", fmt.Errorf("invalid OCI reference: %w", err)
+	}
+
+	// Extract plugin name from the repository path
+	// e.g., "ghcr.io/user/plugin-name:v1.0.0" -> Repository: "user/plugin-name"
+	repository := ref.Repository
+	if repository == "" {
+		return "", fmt.Errorf("invalid OCI reference: missing repository")
+	}
+
+	// Get the last part of the repository path as the plugin name
+	parts := strings.Split(repository, "/")
+	pluginName := parts[len(parts)-1]
+
+	if pluginName == "" {
+		return "", fmt.Errorf("invalid OCI reference: cannot determine plugin name from repository %s", repository)
+	}
+
+	return pluginName, nil
+}

pkg/registry/plugin_test.go

@@ -0,0 +1,93 @@
+/*
+Copyright The Helm Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package registry
+
+import (
+	"testing"
+)
+
+func TestGetPluginName(t *testing.T) {
+	tests := []struct {
+		name      string
+		source    string
+		expected  string
+		expectErr bool
+	}{
+		{
+			name:     "valid OCI reference with tag",
+			source:   "oci://ghcr.io/user/plugin-name:v1.0.0",
+			expected: "plugin-name",
+		},
+		{
+			name:     "valid OCI reference with digest",
+			source:   "oci://ghcr.io/user/plugin-name@sha256:1234567890abcdef",
+			expected: "plugin-name",
+		},
+		{
+			name:     "valid OCI reference without tag",
+			source:   "oci://ghcr.io/user/plugin-name",
+			expected: "plugin-name",
+		},
+		{
+			name:     "valid OCI reference with multiple path segments",
+			source:   "oci://registry.example.com/org/team/plugin-name:latest",
+			expected: "plugin-name",
+		},
+		{
+			name:     "valid OCI reference with plus signs in tag",
+			source:   "oci://registry.example.com/user/plugin-name:v1.0.0+build.1",
+			expected: "plugin-name",
+		},
+		{
+			name:     "valid OCI reference - single path segment",
+			source:   "oci://registry.example.com/plugin",
+			expected: "plugin",
+		},
+		{
+			name:      "invalid OCI reference - no repository",
+			source:    "oci://registry.example.com",
+			expectErr: true,
+		},
+		{
+			name:      "invalid OCI reference - malformed",
+			source:    "not-an-oci-reference",
+			expectErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			pluginName, err := GetPluginName(tt.source)
+
+			if tt.expectErr {
+				if err == nil {
+					t.Errorf("expected error but got none")
+				}
+				return
+			}
+
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+				return
+			}
+
+			if pluginName != tt.expected {
+				t.Errorf("expected plugin name %q, got %q", tt.expected, pluginName)
+			}
+		})
+	}
+}