[8.x] More strict plugin type definitions (#205232) (#205778)

# Backport

This will backport the following commits from `main` to `8.x`:
- [More strict plugin type definitions
(#205232)](#205232)

<!--- Backport version: 9.4.3 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Dario
Gieselaar","email":"[email protected]"},"sourceCommit":{"committedDate":"2025-01-07T15:41:15Z","message":"More
strict plugin type definitions (#205232)\n\nStricter defaults for plugin
types: `Plugin` and `CoreSetup` now have\nempty objects as defaults
instead of `object` which is assignable to\nanything basically. This
catches some type errors, but my motivation for\nthis is to allow
something like:\n\n```ts\nfunction createPlugin
():Plugin<MySetupContract, MyStartContract, MySetupDependencies,
MyStartDependencies> {\n\treturn {\n\t\t// look ma, no additional typing
necessary\n\t\tsetup ( coreSetup, pluginsSetup ) {\n\t\t},\n\t\tstart (
coreStart, pluginsStart )
{\n\t\t}\n\t}\n}\n```","sha":"98ce312ba36cbb7e4fc4a5cf16acc841c2f1b21f","branchLabelMapping":{"^v9.0.0$":"main","^v8.18.0$":"8.x","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:skip","v9.0.0","Team:obs-ux-management","backport:version","v8.18.0"],"title":"More
strict plugin type
definitions","number":205232,"url":"https://github.com/elastic/kibana/pull/205232","mergeCommit":{"message":"More
strict plugin type definitions (#205232)\n\nStricter defaults for plugin
types: `Plugin` and `CoreSetup` now have\nempty objects as defaults
instead of `object` which is assignable to\nanything basically. This
catches some type errors, but my motivation for\nthis is to allow
something like:\n\n```ts\nfunction createPlugin
():Plugin<MySetupContract, MyStartContract, MySetupDependencies,
MyStartDependencies> {\n\treturn {\n\t\t// look ma, no additional typing
necessary\n\t\tsetup ( coreSetup, pluginsSetup ) {\n\t\t},\n\t\tstart (
coreStart, pluginsStart )
{\n\t\t}\n\t}\n}\n```","sha":"98ce312ba36cbb7e4fc4a5cf16acc841c2f1b21f"}},"sourceBranch":"main","suggestedTargetBranches":["8.x"],"targetPullRequestStates":[{"branch":"main","label":"v9.0.0","branchLabelMappingKey":"^v9.0.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/205232","number":205232,"mergeCommit":{"message":"More
strict plugin type definitions (#205232)\n\nStricter defaults for plugin
types: `Plugin` and `CoreSetup` now have\nempty objects as defaults
instead of `object` which is assignable to\nanything basically. This
catches some type errors, but my motivation for\nthis is to allow
something like:\n\n```ts\nfunction createPlugin
():Plugin<MySetupContract, MyStartContract, MySetupDependencies,
MyStartDependencies> {\n\treturn {\n\t\t// look ma, no additional typing
necessary\n\t\tsetup ( coreSetup, pluginsSetup ) {\n\t\t},\n\t\tstart (
coreStart, pluginsStart )
{\n\t\t}\n\t}\n}\n```","sha":"98ce312ba36cbb7e4fc4a5cf16acc841c2f1b21f"}},{"branch":"8.x","label":"v8.18.0","branchLabelMappingKey":"^v8.18.0$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Dario Gieselaar <[email protected]>

examples/eso_model_version_example/server/plugin.ts

@@ -61,7 +61,10 @@ export interface EsoModelVersionExamplePluginsStart {
   encryptedSavedObjects: EncryptedSavedObjectsPluginStart;
 }
 
-export class EsoModelVersionExample implements Plugin<void, void> {
+export class EsoModelVersionExample
+  implements
+    Plugin<void, void, EsoModelVersionExamplePluginSetup, EsoModelVersionExamplePluginsStart>
+{
   public setup(
     core: CoreSetup<EsoModelVersionExamplePluginsStart>,
     plugins: EsoModelVersionExamplePluginSetup

src/core/packages/lifecycle/browser/src/core_setup.ts

@@ -36,7 +36,7 @@ import type { CoreStart } from './core_start';
  * navigation in the generated docs until there's a fix for
  * https://github.com/Microsoft/web-build-tools/issues/1237
  */
-export interface CoreSetup<TPluginsStart extends object = object, TStart = unknown> {
+export interface CoreSetup<TPluginsStart extends Record<string, any> = {}, TStart = unknown> {
   /** {@link AnalyticsServiceSetup} */
   analytics: AnalyticsServiceSetup;
   /** {@link ApplicationSetup} */

src/core/packages/lifecycle/server/src/core_setup.ts

@@ -40,7 +40,7 @@ import type { CoreStart } from './core_start';
  *                     consuming {@link Plugin}'s `TStart` type. Used by `getStartServices`.
  * @public
  */
-export interface CoreSetup<TPluginsStart extends object = object, TStart = unknown> {
+export interface CoreSetup<TPluginsStart extends Record<string, any> = {}, TStart = unknown> {
   /** {@link AnalyticsServiceSetup} */
   analytics: AnalyticsServiceSetup;
   /** {@link CapabilitiesSetup} */

src/core/packages/plugins/browser/src/plugin.ts

@@ -18,8 +18,8 @@ import type { CoreStart, CoreSetup } from '@kbn/core-lifecycle-browser';
 export interface Plugin<
   TSetup = void,
   TStart = void,
-  TPluginsSetup extends object = object,
-  TPluginsStart extends object = object
+  TPluginsSetup extends Record<string, any> = never,
+  TPluginsStart extends Record<string, any> = never
 > {
   setup(core: CoreSetup<TPluginsStart, TStart>, plugins: TPluginsSetup): TSetup;
 

src/core/packages/plugins/browser/src/plugin_initializer.ts

@@ -19,10 +19,10 @@ import type { Plugin } from './plugin';
  * @public
  */
 export type PluginInitializer<
-  TSetup,
-  TStart,
-  TPluginsSetup extends object = object,
-  TPluginsStart extends object = object
+  TSetup = void,
+  TStart = void,
+  TPluginsSetup extends Record<string, any> = never,
+  TPluginsStart extends Record<string, any> = never
 > = (core: PluginInitializerContext) => Plugin<TSetup, TStart, TPluginsSetup, TPluginsStart>;
 
 /**

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

@@ -98,7 +98,7 @@ export class PluginWrapper<
    * is the contract returned by the dependency's `setup` function.
    */
   public setup(
-    setupContext: CoreSetup<TPluginsStart> | CorePreboot,
+    setupContext: CoreSetup<TPluginsStart, TStart> | CorePreboot,
     plugins: TPluginsSetup
   ): TSetup | Promise<TSetup> {
     if (!this.instance) {
@@ -109,7 +109,7 @@ export class PluginWrapper<
       return this.instance.setup(setupContext as CorePreboot, plugins);
     }
 
-    return this.instance.setup(setupContext as CoreSetup, plugins);
+    return this.instance.setup(setupContext as CoreSetup<TPluginsStart, TStart>, plugins);
   }
 
   /**

src/core/packages/plugins/server/src/types.ts

@@ -291,10 +291,10 @@ export interface PrebootPlugin<TSetup = void, TPluginsSetup extends object = obj
 export interface Plugin<
   TSetup = void,
   TStart = void,
-  TPluginsSetup extends object = object,
-  TPluginsStart extends object = object
+  TPluginsSetup extends Record<string, any> = {},
+  TPluginsStart extends Record<string, any> = {}
 > {
-  setup(core: CoreSetup, plugins: TPluginsSetup): TSetup;
+  setup(core: CoreSetup<TPluginsStart, TStart>, plugins: TPluginsSetup): TSetup;
 
   start(core: CoreStart, plugins: TPluginsStart): TStart;
 
@@ -451,10 +451,10 @@ export interface PluginInitializerContext<ConfigSchema = unknown> {
  * @public
  */
 export type PluginInitializer<
-  TSetup,
-  TStart,
-  TPluginsSetup extends object = object,
-  TPluginsStart extends object = object
+  TSetup = void,
+  TStart = void,
+  TPluginsSetup extends Record<string, any> = never,
+  TPluginsStart extends Record<string, any> = never
 > = (
   core: PluginInitializerContext
 ) => Promise<

src/platform/plugins/private/maps_ems/server/plugin.ts

@@ -54,5 +54,7 @@ export class MapsEmsPlugin implements Plugin<MapsEmsPluginServerSetup> {
     };
   }
 
-  public start() {}
+  public start() {
+    return {};
+  }
 }

src/platform/plugins/shared/dashboard/server/plugin.ts

@@ -45,15 +45,15 @@ interface StartDeps {
 }
 
 export class DashboardPlugin
-  implements Plugin<DashboardPluginSetup, DashboardPluginStart, SetupDeps>
+  implements Plugin<DashboardPluginSetup, DashboardPluginStart, SetupDeps, StartDeps>
 {
   private readonly logger: Logger;
 
   constructor(private initializerContext: PluginInitializerContext) {
     this.logger = initializerContext.logger.get();
   }
 
-  public setup(core: CoreSetup<StartDeps>, plugins: SetupDeps) {
+  public setup(core: CoreSetup<StartDeps, DashboardPluginStart>, plugins: SetupDeps) {
     this.logger.debug('dashboard: Setup');
 
     core.savedObjects.registerType(

src/plugins/data/server/search/search_service.ts

@@ -15,7 +15,6 @@ import {
   CoreStart,
   KibanaRequest,
   Logger,
-  Plugin,
   PluginInitializerContext,
   SharedGlobalConfig,
   StartServicesAccessor,
@@ -124,7 +123,7 @@ export interface SearchRouteDependencies {
   globalConfig$: Observable<SharedGlobalConfig>;
 }
 
-export class SearchService implements Plugin<ISearchSetup, ISearchStart> {
+export class SearchService {
   private readonly aggsService = new AggsService();
   private readonly searchSourceService = new SearchSourceService();
   private searchStrategies: StrategyMap = {};

src/plugins/unified_search/server/plugin.ts

@@ -25,7 +25,15 @@ export interface UnifiedSearchServerPluginSetupDependencies {}
 // eslint-disable-next-line @typescript-eslint/no-empty-interface
 export interface UnifiedSearchServerPluginStartDependencies {}
 
-export class UnifiedSearchServerPlugin implements Plugin<UnifiedSearchServerPluginSetup> {
+export class UnifiedSearchServerPlugin
+  implements
+    Plugin<
+      UnifiedSearchServerPluginSetup,
+      UnifiedSearchServerPluginStart,
+      UnifiedSearchServerPluginSetupDependencies,
+      UnifiedSearchServerPluginStartDependencies
+    >
+{
   private readonly autocompleteService: AutocompleteService;
 
   constructor(initializerContext: PluginInitializerContext<ConfigSchema>) {

src/plugins/vis_types/timeseries/server/plugin.ts

@@ -82,7 +82,15 @@ export interface Framework {
   getEsShardTimeout: () => Promise<number>;
 }
 
-export class VisTypeTimeseriesPlugin implements Plugin<VisTypeTimeseriesSetup> {
+export class VisTypeTimeseriesPlugin
+  implements
+    Plugin<
+      VisTypeTimeseriesSetup,
+      void,
+      VisTypeTimeseriesPluginSetupDependencies,
+      VisTypeTimeseriesPluginStartDependencies
+    >
+{
   constructor(private readonly initializerContext: PluginInitializerContext) {
     this.initializerContext = initializerContext;
   }

x-pack/examples/gen_ai_streaming_response_example/server/plugin.ts

@@ -26,7 +26,9 @@ interface MessageBody {
   messages: Message[];
 }
 
-export class GenAiStreamingResponseExamplePlugin implements Plugin<void, void> {
+export class GenAiStreamingResponseExamplePlugin
+  implements Plugin<void, void, {}, GenAiStreamingResponseExamplePluginStart>
+{
   public setup({ http, getStartServices }: CoreSetup<GenAiStreamingResponseExamplePluginStart>) {
     const router = http.createRouter();
 

x-pack/examples/screenshotting_example/server/plugin.ts

@@ -15,7 +15,7 @@ interface StartDeps {
   screenshotting: ScreenshottingStart;
 }
 
-export class ScreenshottingExamplePlugin implements Plugin<void, void> {
+export class ScreenshottingExamplePlugin implements Plugin<void, void, {}, StartDeps> {
   setup({ http, getStartServices }: CoreSetup<StartDeps>) {
     const router = http.createRouter();
 

x-pack/platform/plugins/private/canvas/server/plugin.ts

@@ -41,7 +41,7 @@ interface PluginsStart {
   data: DataPluginStart;
 }
 
-export class CanvasPlugin implements Plugin {
+export class CanvasPlugin implements Plugin<void, void, PluginsSetup, PluginsStart> {
   private readonly logger: Logger;
 
   constructor(public readonly initializerContext: PluginInitializerContext) {

x-pack/platform/plugins/private/data_visualizer/server/plugin.ts

@@ -17,7 +17,7 @@ import { registerWithCustomIntegrations } from './register_custom_integration';
 import { routes } from './routes';
 import type { ConfigSchema } from '../common/app';
 
-export class DataVisualizerPlugin implements Plugin {
+export class DataVisualizerPlugin implements Plugin<void, void, SetupDeps, StartDeps> {
   private readonly _logger: Logger;
 
   constructor(initializerContext: PluginInitializerContext<ConfigSchema>) {

x-pack/platform/plugins/shared/actions/server/plugin.ts

@@ -208,7 +208,10 @@ const includedHiddenTypes = [
   CONNECTOR_TOKEN_SAVED_OBJECT_TYPE,
 ];
 
-export class ActionsPlugin implements Plugin<PluginSetupContract, PluginStartContract> {
+export class ActionsPlugin
+  implements
+    Plugin<PluginSetupContract, PluginStartContract, ActionsPluginsSetup, ActionsPluginsStart>
+{
   private readonly logger: Logger;
   private readonly actionsConfig: ActionsConfig;
   private taskRunnerFactory?: TaskRunnerFactory;
@@ -237,7 +240,7 @@ export class ActionsPlugin implements Plugin<PluginSetupContract, PluginStartCon
   }
 
   public setup(
-    core: CoreSetup<ActionsPluginsStart>,
+    core: CoreSetup<ActionsPluginsStart, PluginStartContract>,
     plugins: ActionsPluginsSetup
   ): PluginSetupContract {
     this.licenseState = new LicenseState(plugins.licensing.license$);

x-pack/platform/plugins/shared/integration_assistant/server/plugin.ts

@@ -13,29 +13,36 @@ import type {
   Logger,
   CustomRequestHandlerContext,
 } from '@kbn/core/server';
-import type { PluginStartContract as ActionsPluginsStart } from '@kbn/actions-plugin/server/plugin';
 import { MINIMUM_LICENSE_TYPE } from '../common/constants';
 import { registerRoutes } from './routes';
 import type {
   IntegrationAssistantPluginSetup,
   IntegrationAssistantPluginStart,
   IntegrationAssistantPluginStartDependencies,
+  IntegrationAssistantPluginSetupDependencies,
 } from './types';
 import { parseExperimentalConfigValue } from '../common/experimental_features';
 import { IntegrationAssistantConfigType } from './config';
 
 export type IntegrationAssistantRouteHandlerContext = CustomRequestHandlerContext<{
   integrationAssistant: {
-    getStartServices: CoreSetup<{
-      actions: ActionsPluginsStart;
-    }>['getStartServices'];
+    getStartServices: CoreSetup<
+      IntegrationAssistantPluginStartDependencies,
+      IntegrationAssistantPluginStart
+    >['getStartServices'];
     isAvailable: () => boolean;
     logger: Logger;
   };
 }>;
 
 export class IntegrationAssistantPlugin
-  implements Plugin<IntegrationAssistantPluginSetup, IntegrationAssistantPluginStart>
+  implements
+    Plugin<
+      IntegrationAssistantPluginSetup,
+      IntegrationAssistantPluginStart,
+      IntegrationAssistantPluginSetupDependencies,
+      IntegrationAssistantPluginStartDependencies
+    >
 {
   private readonly logger: Logger;
   private readonly config: IntegrationAssistantConfigType;
@@ -50,9 +57,7 @@ export class IntegrationAssistantPlugin
   }
 
   public setup(
-    core: CoreSetup<{
-      actions: ActionsPluginsStart;
-    }>
+    core: CoreSetup<IntegrationAssistantPluginStartDependencies, IntegrationAssistantPluginStart>
   ): IntegrationAssistantPluginSetup {
     core.http.registerRouteHandlerContext<
       IntegrationAssistantRouteHandlerContext,

x-pack/platform/plugins/shared/integration_assistant/server/types.ts

@@ -12,6 +12,10 @@ import {
   ActionsClientSimpleChatModel,
 } from '@kbn/langchain/server';
 import type { LicensingPluginSetup, LicensingPluginStart } from '@kbn/licensing-plugin/server';
+import type {
+  PluginStartContract as ActionsPluginStart,
+  PluginSetupContract as ActionsPluginSetup,
+} from '@kbn/actions-plugin/server/plugin';
 import { ESProcessorItem, SamplesFormat } from '../common';
 
 export interface IntegrationAssistantPluginSetup {
@@ -22,9 +26,11 @@ export interface IntegrationAssistantPluginStart {}
 
 export interface IntegrationAssistantPluginSetupDependencies {
   licensing: LicensingPluginSetup;
+  actions: ActionsPluginSetup;
 }
 export interface IntegrationAssistantPluginStartDependencies {
   licensing: LicensingPluginStart;
+  actions: ActionsPluginStart;
 }
 
 export interface SimplifiedProcessor {

x-pack/platform/plugins/shared/maps/server/plugin.ts

@@ -35,7 +35,7 @@ import { registerIntegrations } from './register_integrations';
 import { StartDeps, SetupDeps } from './types';
 import { MapsStorage } from './content_management';
 
-export class MapsPlugin implements Plugin {
+export class MapsPlugin implements Plugin<void, void, SetupDeps, StartDeps> {
   readonly _initializerContext: PluginInitializerContext<MapsXPackConfig>;
   private readonly _logger: Logger;
 

x-pack/platform/plugins/shared/observability_solution/dataset_quality/server/plugin.ts

@@ -12,12 +12,21 @@ import { getDatasetQualityServerRouteRepository } from './routes';
 import { registerRoutes } from './routes/register_routes';
 import { DatasetQualityRouteHandlerResources } from './routes/types';
 import {
+  DatasetQualityPluginSetup,
   DatasetQualityPluginSetupDependencies,
   DatasetQualityPluginStart,
   DatasetQualityPluginStartDependencies,
 } from './types';
 
-export class DatasetQualityServerPlugin implements Plugin {
+export class DatasetQualityServerPlugin
+  implements
+    Plugin<
+      DatasetQualityPluginSetup,
+      DatasetQualityPluginStart,
+      DatasetQualityPluginSetupDependencies,
+      DatasetQualityPluginStartDependencies
+    >
+{
   private readonly logger: Logger;
   private readonly dataTelemetryService: DataTelemetryService;
 

x-pack/platform/plugins/shared/stack_connectors/server/plugin.ts

@@ -26,7 +26,9 @@ export interface ConnectorsPluginsStart {
   actions: ActionsPluginSetupContract;
 }
 
-export class StackConnectorsPlugin implements Plugin<void, void> {
+export class StackConnectorsPlugin
+  implements Plugin<void, void, ConnectorsPluginsSetup, ConnectorsPluginsStart>
+{
   private readonly logger: Logger;
   private config: StackConnectorsConfigType;
   readonly experimentalFeatures: ExperimentalFeatures;

x-pack/platform/plugins/shared/task_manager/server/kibana_discovery_service/delete_inactive_nodes_task.ts

@@ -12,6 +12,7 @@ import { TaskTypeDictionary } from '../task_type_dictionary';
 import { BackgroundTaskNode } from '../saved_objects/schemas/background_task_node';
 import { BACKGROUND_TASK_NODE_SO_NAME } from '../saved_objects';
 import { TaskManagerStartContract } from '..';
+import { TaskManagerPluginsStart } from '../plugin';
 
 export const TASK_ID = 'delete_inactive_background_task_nodes';
 const TASK_TYPE = `task_manager:${TASK_ID}`;
@@ -40,7 +41,7 @@ export async function scheduleDeleteInactiveNodesTaskDefinition(
 
 export function registerDeleteInactiveNodesTaskDefinition(
   logger: Logger,
-  coreStartServices: () => Promise<[CoreStart, TaskManagerStartContract, unknown]>,
+  coreStartServices: () => Promise<[CoreStart, TaskManagerPluginsStart, TaskManagerStartContract]>,
   taskTypeDictionary: TaskTypeDictionary
 ) {
   taskTypeDictionary.registerTaskDefinitions({
@@ -53,7 +54,7 @@ export function registerDeleteInactiveNodesTaskDefinition(
 
 export function taskRunner(
   logger: Logger,
-  coreStartServices: () => Promise<[CoreStart, TaskManagerStartContract, unknown]>
+  coreStartServices: () => Promise<[CoreStart, TaskManagerPluginsStart, TaskManagerStartContract]>
 ) {
   return () => {
     return {