Add enforcement logic to prevent cross-solution plugin dependencies.

packages/core/plugins/core-plugins-server-internal/src/discovery/plugins_discovery.ts

@@ -89,6 +89,7 @@ export function discover({
         manifest,
         opaqueId: initializerContext.opaqueId,
         initializerContext,
+        categoryInfo: pkg.getPluginCategories(),
       });
     })
   );

packages/core/plugins/core-plugins-server-internal/src/plugin.test.ts

@@ -43,10 +43,10 @@ jest.doMock(join('plugin-with-wrong-initializer-path', 'server'), () => ({ plugi
   virtual: true,
 });
 
-const OSS_PLUGIN_PATH_POSIX = '/kibana/src/plugins/ossPlugin';
-const OSS_PLUGIN_PATH_WINDOWS = 'C:\\kibana\\src\\plugins\\ossPlugin';
-const XPACK_PLUGIN_PATH_POSIX = '/kibana/x-pack/plugins/xPackPlugin';
-const XPACK_PLUGIN_PATH_WINDOWS = 'C:\\kibana\\x-pack\\plugins\\xPackPlugin';
+const OSS_PLUGIN_PATH_POSIX = '/kibana/src/foo/ossPlugin';
+const OSS_PLUGIN_PATH_WINDOWS = 'C:\\kibana\\src\\foo\\ossPlugin';
+const XPACK_PLUGIN_PATH_POSIX = '/kibana/x-pack/foo/xPackPlugin';
+const XPACK_PLUGIN_PATH_WINDOWS = 'C:\\kibana\\x-pack\\foo\\xPackPlugin';
 
 function createPluginManifest(manifestProps: Partial<PluginManifest> = {}): PluginManifest {
   return {

packages/core/plugins/core-plugins-server-internal/src/plugin.ts

@@ -11,6 +11,7 @@ import typeDetect from 'type-detect';
 import { firstValueFrom, Subject } from 'rxjs';
 import { isPromise } from '@kbn/std';
 import { isConfigSchema } from '@kbn/config-schema';
+import type { PluginCategoryInfo } from '@kbn/repo-packages';
 import type { Logger } from '@kbn/logging';
 import { type PluginOpaqueId, PluginType } from '@kbn/core-base-common';
 import type {
@@ -24,8 +25,8 @@ import type {
 } from '@kbn/core-plugins-server';
 import type { CorePreboot, CoreSetup, CoreStart } from '@kbn/core-lifecycle-server';
 
-const OSS_PATH_REGEX = /[\/|\\]src[\/|\\]plugins[\/|\\]/; // Matches src/plugins directory on POSIX and Windows
-const XPACK_PATH_REGEX = /[\/|\\]x-pack[\/|\\]plugins[\/|\\]/; // Matches x-pack/plugins directory on POSIX and Windows
+const OSS_PATH_REGEX = /[\/|\\]src[\/|\\]/; // Matches src/ directory on POSIX and Windows
+const XPACK_PATH_REGEX = /[\/|\\]x-pack[\/|\\]/; // Matches x-pack/ directory on POSIX and Windows
 
 /**
  * Lightweight wrapper around discovered plugin that is responsible for instantiating
@@ -51,6 +52,7 @@ export class PluginWrapper<
   public readonly requiredBundles: PluginManifest['requiredBundles'];
   public readonly includesServerPlugin: PluginManifest['server'];
   public readonly includesUiPlugin: PluginManifest['ui'];
+  public readonly categoryInfo?: PluginCategoryInfo;
 
   private readonly log: Logger;
   private readonly initializerContext: PluginInitializerContext;
@@ -69,6 +71,7 @@ export class PluginWrapper<
       readonly manifest: PluginManifest;
       readonly opaqueId: PluginOpaqueId;
       readonly initializerContext: PluginInitializerContext;
+      readonly categoryInfo?: PluginCategoryInfo;
     }
   ) {
     this.path = params.path;
@@ -85,6 +88,7 @@ export class PluginWrapper<
     this.runtimePluginDependencies = params.manifest.runtimePluginDependencies;
     this.includesServerPlugin = params.manifest.server;
     this.includesUiPlugin = params.manifest.ui;
+    this.categoryInfo = params.categoryInfo;
   }
 
   public async init() {

packages/core/plugins/core-plugins-server-internal/src/plugins_service.ts

@@ -368,7 +368,14 @@ export class PluginsService
     plugin: PluginWrapper,
     pluginEnableStatuses: Map<PluginName, { plugin: PluginWrapper; isEnabled: boolean }>
   ) {
-    const { name, manifest, requiredBundles, requiredPlugins } = plugin;
+    const {
+      name,
+      manifest,
+      optionalPlugins,
+      requiredBundles,
+      requiredPlugins,
+      runtimePluginDependencies,
+    } = plugin;
 
     // validate that `requiredBundles` ids point to a discovered plugin which `includesUiPlugin`
     for (const requiredBundleId of requiredBundles) {
@@ -403,6 +410,44 @@ export class PluginsService
         }
       }
     }
+
+    // validate that non-platform plugins do not have dependencies on each other
+    for (const id of [
+      ...requiredPlugins,
+      ...requiredBundles,
+      ...optionalPlugins,
+      ...runtimePluginDependencies,
+    ]) {
+      const dependency = pluginEnableStatuses.get(id);
+      const pluginTier = this.getPluginTier(plugin);
+      const dependencyPluginTier = this.getPluginTier(dependency?.plugin);
+      if (
+        dependency &&
+        !this.isPublicPlatformPlugin(dependency.plugin) &&
+        pluginTier !== dependencyPluginTier
+      ) {
+        throw new Error(
+          `Plugin or bundle with id "${id}" is required by plugin "${name}", which is prohibited. Plugin "${name}" may only have dependencies on public platform plugins, or other ${pluginTier} plugins.`
+        );
+      }
+    }
+  }
+
+  private getPluginTier(plugin?: PluginWrapper) {
+    if (plugin?.categoryInfo?.platform) return 'platform';
+    if (plugin?.categoryInfo?.observability) return 'observability';
+    if (plugin?.categoryInfo?.search) return 'search';
+    if (plugin?.categoryInfo?.security) return 'security';
+    return 'unknown';
+  }
+
+  private isPublicPlatformPlugin(plugin: PluginWrapper) {
+    const isPlatformPlugin = this.getPluginTier(plugin) === 'platform';
+    // TODO: find a nicer way to do this
+    const isInternalPlatformPlugin =
+      plugin.path.includes('src/platform/internal') ||
+      plugin.path.includes('x-pack/platform/internal');
+    return isPlatformPlugin && !isInternalPlatformPlugin;
   }
 
   private shouldEnablePlugin(

packages/kbn-repo-packages/modern/package.js

@@ -157,10 +157,19 @@ class Package {
     const oss = !dir.startsWith('x-pack/');
     const example = dir.startsWith('examples/') || dir.startsWith('x-pack/examples/');
     const testPlugin = dir.startsWith('test/') || dir.startsWith('x-pack/test/');
+    const platform = dir.startsWith('src/platform/') || dir.startsWith('x-pack/platform/');
+    const observability =
+      dir.startsWith('src/observability/') || dir.startsWith('x-pack/observability/');
+    const search = dir.startsWith('src/search/') || dir.startsWith('x-pack/search/');
+    const security = dir.startsWith('src/security/') || dir.startsWith('x-pack/security/');
     return {
       oss,
       example,
       testPlugin,
+      platform,
+      observability,
+      search,
+      security,
     };
   }
 

packages/kbn-repo-packages/modern/types.ts

@@ -194,4 +194,12 @@ export interface PluginCategoryInfo {
   example: boolean;
   /** is this a test plugin? */
   testPlugin: boolean;
+  /** is this a platform plugin? */
+  platform: boolean;
+  /** is this a observability plugin? */
+  observability: boolean;
+  /** is this a search plugin? */
+  search: boolean;
+  /** is this a security plugin? */
+  security: boolean;
 }