fix: improve plugin name validation error messages

Signed-off-by: Benoit Tigeot <benoit.tigeot@lifen.fr>

internal/plugin/metadata_legacy.go

@@ -69,7 +69,10 @@ type MetadataLegacy struct {
 
 func (m *MetadataLegacy) Validate() error {
 	if !validPluginName.MatchString(m.Name) {
-		return fmt.Errorf("invalid plugin name")
+		if m.Name == "" {
+			return fmt.Errorf("plugin name is empty or missing: ensure plugin.yaml contains 'name:' field (lowercase)")
+		}
+		return fmt.Errorf("invalid plugin name %q: plugin names can only contain ASCII characters a-z, A-Z, 0-9, _ and -", m.Name)
 	}
 	m.Usage = sanitizeString(m.Usage)
 

internal/plugin/metadata_legacy_test.go

@@ -0,0 +1,55 @@
+/*
+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 plugin
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestMetadataLegacyValidate_EmptyName(t *testing.T) {
+	metadata := MetadataLegacy{
+		Name:    "",
+		Version: "1.0.0",
+	}
+
+	err := metadata.Validate()
+	if err == nil {
+		t.Fatal("expected error for empty plugin name")
+	}
+
+	expectedMsg := "plugin name is empty or missing"
+	if !strings.Contains(err.Error(), expectedMsg) {
+		t.Errorf("expected error to contain %q, got %q", expectedMsg, err.Error())
+	}
+}
+
+func TestMetadataLegacyValidate_InvalidName(t *testing.T) {
+	metadata := MetadataLegacy{
+		Name:    "invalid name",
+		Version: "1.0.0",
+	}
+
+	err := metadata.Validate()
+	if err == nil {
+		t.Fatal("expected error for invalid plugin name")
+	}
+
+	expectedMsg := "plugin names can only contain ASCII characters"
+	if !strings.Contains(err.Error(), expectedMsg) {
+		t.Errorf("expected error to contain %q, got %q", expectedMsg, err.Error())
+	}
+}