feat(extensions): enforce collision policy for duplicate entity identities

Author: hopehadfield

workspaces/extensions/plugins/catalog-backend-module-extensions/src/providers/BaseEntityProvider.test.ts

@@ -0,0 +1,125 @@
+/*
+ * Copyright Red Hat, Inc.
+ *
+ * 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.
+ */
+
+import { Entity } from '@backstage/catalog-model';
+import { SchedulerServiceTaskRunner } from '@backstage/backend-plugin-api';
+import { BaseEntityProvider } from './BaseEntityProvider';
+import { JsonFileData } from '../types';
+
+class TestEntityProvider extends BaseEntityProvider<Entity> {
+  getProviderName(): string {
+    return 'test-entity-provider';
+  }
+
+  getKind(): string {
+    return 'Plugin';
+  }
+}
+
+const taskRunner: SchedulerServiceTaskRunner = {
+  run: jest.fn(async ({ fn }) => fn()),
+};
+
+const createEntity = (overrides?: Partial<Entity>): Entity => ({
+  apiVersion: 'extensions.backstage.io/v1alpha1',
+  kind: 'Plugin',
+  metadata: {
+    name: 'duplicate-plugin',
+    ...overrides?.metadata,
+  },
+  spec: {
+    owner: 'test-owner',
+    ...(overrides?.spec as object),
+  },
+  ...overrides,
+});
+
+const createFileData = (
+  filePath: string,
+  entity: Entity,
+): JsonFileData<Entity> => ({
+  filePath,
+  content: entity,
+});
+
+describe('BaseEntityProvider collision policy', () => {
+  beforeEach(() => {
+    jest.spyOn(console, 'warn').mockImplementation(() => undefined);
+  });
+
+  afterEach(() => {
+    jest.restoreAllMocks();
+  });
+
+  it('keeps first definition when duplicate entities are equivalent', () => {
+    const provider = new TestEntityProvider(taskRunner);
+    const duplicate = createEntity();
+
+    const entities = provider.getEntities([
+      createFileData('/extensions/primary/plugin.yaml', duplicate),
+      createFileData('/extensions/extra/community/plugin.yaml', duplicate),
+    ]);
+
+    expect(entities).toHaveLength(1);
+    expect(console.warn).toHaveBeenCalledWith(
+      expect.stringContaining(
+        "Skipping duplicate Extensions entity 'plugin/default/duplicate-plugin'",
+      ),
+    );
+  });
+
+  it('throws when duplicate entities have conflicting definitions', () => {
+    const provider = new TestEntityProvider(taskRunner);
+    const firstEntity = createEntity({
+      spec: { owner: 'owner-a' },
+    });
+    const secondEntity = createEntity({
+      spec: { owner: 'owner-b' },
+    });
+
+    expect(() =>
+      provider.getEntities([
+        createFileData('/extensions/primary/plugin.yaml', firstEntity),
+        createFileData('/extensions/extra/community/plugin.yaml', secondEntity),
+      ]),
+    ).toThrow(
+      "Conflicting Extensions entities detected for 'plugin/default/duplicate-plugin'",
+    );
+  });
+
+  it('keeps entities with same name when namespaces differ', () => {
+    const provider = new TestEntityProvider(taskRunner);
+    const defaultNamespaceEntity = createEntity({
+      metadata: { name: 'shared-name' },
+    });
+    const customNamespaceEntity = createEntity({
+      metadata: { name: 'shared-name', namespace: 'community' },
+    });
+
+    const entities = provider.getEntities([
+      createFileData(
+        '/extensions/primary/plugin-default.yaml',
+        defaultNamespaceEntity,
+      ),
+      createFileData(
+        '/extensions/extra/community/plugin-custom.yaml',
+        customNamespaceEntity,
+      ),
+    ]);
+
+    expect(entities).toHaveLength(2);
+  });
+});

workspaces/extensions/plugins/catalog-backend-module-extensions/src/providers/BaseEntityProvider.ts

@@ -28,6 +28,7 @@ import { readYamlFiles } from '../utils/file-utils';
 import { JsonFileData } from '../types';
 import path from 'path';
 import fs from 'fs';
+import { isDeepStrictEqual } from 'node:util';
 
 /**
  * @public
@@ -50,23 +51,69 @@ export abstract class BaseEntityProvider<T extends Entity>
   abstract getProviderName(): string;
   abstract getKind(): string;
 
+  private getEntityIdentity(entity: Entity): string {
+    const namespace = entity.metadata.namespace ?? 'default';
+    return [
+      entity.kind.toLocaleLowerCase('en-US'),
+      namespace.toLocaleLowerCase('en-US'),
+      entity.metadata.name.toLocaleLowerCase('en-US'),
+    ].join('/');
+  }
+
+  private addProviderAnnotations(entity: T): T {
+    return {
+      ...entity,
+      metadata: {
+        ...entity.metadata,
+        annotations: {
+          ...entity.metadata.annotations,
+          [ANNOTATION_LOCATION]: `file:${this.getProviderName()}`,
+          [ANNOTATION_ORIGIN_LOCATION]: `file:${this.getProviderName()}`,
+        },
+      },
+    };
+  }
+
   getEntities(allEntities: JsonFileData<T>[]): T[] {
     if (allEntities.length === 0) {
       return [];
     }
-    return allEntities
-      .filter(d => d.content.kind === this.getKind())
-      .map(file => ({
-        ...file.content,
-        metadata: {
-          ...file.content.metadata,
-          annotations: {
-            ...file.content.metadata.annotations,
-            [ANNOTATION_LOCATION]: `file:${this.getProviderName()}`,
-            [ANNOTATION_ORIGIN_LOCATION]: `file:${this.getProviderName()}`,
-          },
-        },
-      }));
+
+    const entitiesByIdentity = new Map<
+      string,
+      { entity: T; filePath: string }
+    >();
+
+    for (const fileData of allEntities) {
+      if (fileData.content.kind !== this.getKind()) {
+        continue;
+      }
+
+      const identity = this.getEntityIdentity(fileData.content);
+      const existing = entitiesByIdentity.get(identity);
+      if (!existing) {
+        entitiesByIdentity.set(identity, {
+          entity: fileData.content,
+          filePath: fileData.filePath,
+        });
+        continue;
+      }
+
+      if (isDeepStrictEqual(existing.entity, fileData.content)) {
+        console.warn(
+          `Skipping duplicate Extensions entity '${identity}' from '${fileData.filePath}'. Keeping first definition from '${existing.filePath}'.`,
+        );
+        continue;
+      }
+
+      throw new Error(
+        `Conflicting Extensions entities detected for '${identity}' in '${existing.filePath}' and '${fileData.filePath}'.`,
+      );
+    }
+
+    return Array.from(entitiesByIdentity.values()).map(({ entity }) =>
+      this.addProviderAnnotations(entity),
+    );
   }
 
   async connect(connection: EntityProviderConnection): Promise<void> {