[Cases] Make spaces plugin optional (#150252)

## Summary

This PR makes the spaces plugin an optional dependency for the cases
plugin.

Related: #149687

### Checklist

Delete any items that are not applicable to this PR.

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

### For maintainers

- [x] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

x-pack/plugins/cases/kibana.jsonc

@@ -23,14 +23,14 @@
       "kibanaUtils",
       "triggersActionsUi",
       "management",
-      "spaces",
       "security",
       "notifications"
     ],
     "optionalPlugins": [
       "home",
       "taskManager",
-      "usageCollection"
+      "usageCollection",
+      "spaces"
     ],
     "requiredBundles": [
       "savedObjects"

x-pack/plugins/cases/server/authorization/authorization.test.ts

@@ -69,6 +69,38 @@ describe('authorization', () => {
       await expect(authPromise).resolves.not.toThrow();
     });
 
+    it('creates an Authorization object without spaces', async () => {
+      expect.assertions(2);
+
+      const authPromise = Authorization.create({
+        request,
+        securityAuth: securityStart.authz,
+        features: featuresStart,
+        auditLogger: new AuthorizationAuditLogger(mockLogger),
+        logger: loggingSystemMock.createLogger(),
+      });
+
+      await expect(authPromise).resolves.toBeDefined();
+      await expect(authPromise).resolves.not.toThrow();
+    });
+
+    it('if spaces are disabled it does not filtered out disabled features', async () => {
+      (spacesStart.spacesService.getActiveSpace as jest.Mock).mockImplementation(() => {
+        return { disabledFeatures: ['1'] } as Space;
+      });
+
+      const auth = await Authorization.create({
+        request,
+        securityAuth: securityStart.authz,
+        features: featuresStart,
+        auditLogger: new AuthorizationAuditLogger(mockLogger),
+        logger: loggingSystemMock.createLogger(),
+      });
+
+      // @ts-expect-error: featureCaseOwners is a private method of the auth class
+      expect([...auth.featureCaseOwners.values()]).toEqual(['a']);
+    });
+
     it('throws and error when a failure occurs', async () => {
       expect.assertions(1);
 

x-pack/plugins/cases/server/authorization/authorization.ts

@@ -57,19 +57,21 @@ export class Authorization {
   }: {
     request: KibanaRequest;
     securityAuth?: SecurityPluginStart['authz'];
-    spaces: SpacesPluginStart;
+    spaces?: SpacesPluginStart;
     features: FeaturesPluginStart;
     auditLogger: AuthorizationAuditLogger;
     logger: Logger;
   }): Promise<Authorization> {
-    const getSpace = async (): Promise<Space> => {
-      return spaces.spacesService.getActiveSpace(request);
+    const getSpace = async (): Promise<Space | undefined> => {
+      return spaces?.spacesService.getActiveSpace(request);
     };
 
     // Since we need to do async operations, this static method handles that before creating the Auth class
     let caseOwners: Set<string>;
+
     try {
-      const disabledFeatures = new Set((await getSpace()).disabledFeatures ?? []);
+      const maybeSpace = await getSpace();
+      const disabledFeatures = new Set(maybeSpace?.disabledFeatures ?? []);
 
       caseOwners = new Set(
         features

x-pack/plugins/cases/server/client/factory.ts

@@ -26,6 +26,7 @@ import type { LensServerPluginSetup } from '@kbn/lens-plugin/server';
 import type { SpacesPluginStart } from '@kbn/spaces-plugin/server';
 import type { LicensingPluginStart } from '@kbn/licensing-plugin/server';
 import type { NotificationsPluginStart } from '@kbn/notifications-plugin/server';
+import { DEFAULT_SPACE_ID } from '@kbn/spaces-plugin/common';
 import { SAVED_OBJECT_TYPES } from '../../common/constants';
 import { Authorization } from '../authorization/authorization';
 import {
@@ -49,7 +50,7 @@ import { EmailNotificationService } from '../services/notifications/email_notifi
 interface CasesClientFactoryArgs {
   securityPluginSetup: SecurityPluginSetup;
   securityPluginStart: SecurityPluginStart;
-  spacesPluginStart: SpacesPluginStart;
+  spacesPluginStart?: SpacesPluginStart;
   featuresPluginStart: FeaturesPluginStart;
   actionsPluginStart: ActionsPluginStart;
   licensingPluginStart: LicensingPluginStart;
@@ -144,7 +145,8 @@ export class CasesClientFactory {
       externalReferenceAttachmentTypeRegistry: this.options.externalReferenceAttachmentTypeRegistry,
       securityStartPlugin: this.options.securityPluginStart,
       publicBaseUrl: this.options.publicBaseUrl,
-      spaceId: this.options.spacesPluginStart.spacesService.getSpaceId(request),
+      spaceId:
+        this.options.spacesPluginStart?.spacesService.getSpaceId(request) ?? DEFAULT_SPACE_ID,
       savedObjectsSerializer,
     });
   }
@@ -197,7 +199,8 @@ export class CasesClientFactory {
       notifications: this.options.notifications,
       security: this.options.securityPluginStart,
       publicBaseUrl: this.options.publicBaseUrl,
-      spaceId: this.options.spacesPluginStart.spacesService.getSpaceId(request),
+      spaceId:
+        this.options.spacesPluginStart?.spacesService.getSpaceId(request) ?? DEFAULT_SPACE_ID,
     });
 
     return {

x-pack/plugins/cases/server/plugin.ts

@@ -72,7 +72,7 @@ export interface PluginsStart {
   licensing: LicensingPluginStart;
   taskManager?: TaskManagerStartContract;
   security: SecurityPluginStart;
-  spaces: SpacesPluginStart;
+  spaces?: SpacesPluginStart;
   notifications: NotificationsPluginStart;
 }
 

x-pack/plugins/cases/server/services/user_profiles/index.ts

@@ -14,6 +14,7 @@ import type { KibanaRequest, Logger } from '@kbn/core/server';
 import type { SecurityPluginSetup, SecurityPluginStart } from '@kbn/security-plugin/server';
 import type { UserProfile } from '@kbn/security-plugin/common';
 import type { SpacesPluginStart } from '@kbn/spaces-plugin/server';
+import { DEFAULT_SPACE_ID } from '@kbn/spaces-plugin/common';
 
 import type { LicensingPluginStart } from '@kbn/licensing-plugin/server';
 import { excess, SuggestUserProfilesRequestRt, throwErrors } from '../../../common/api';
@@ -28,7 +29,7 @@ const MIN_PROFILES_SIZE = 0;
 interface UserProfileOptions {
   securityPluginSetup: SecurityPluginSetup;
   securityPluginStart: SecurityPluginStart;
-  spaces: SpacesPluginStart;
+  spaces?: SpacesPluginStart;
   licensingPluginStart: LicensingPluginStart;
 }
 
@@ -110,7 +111,7 @@ export class UserProfileService {
         size,
         owners,
         securityPluginStart: this.options.securityPluginStart,
-        spaceId: spaces.spacesService.getSpaceId(request),
+        spaceId: spaces?.spacesService.getSpaceId(request) ?? DEFAULT_SPACE_ID,
       });
     } catch (error) {
       throw createCaseError({