Don't expose core namespace conversion methods in the public contract

This partially reverts commit fa6ae1c.

docs/development/core/server/kibana-plugin-core-server.md

@@ -224,8 +224,6 @@ The plugin integrates with the core system via lifecycle events: `setup`<!-- -->
 |  Variable | Description |
 |  --- | --- |
 |  [kibanaResponseFactory](./kibana-plugin-core-server.kibanaresponsefactory.md) | Set of helpers used to create <code>KibanaResponse</code> to form HTTP response on an incoming request. Should be returned as a result of [RequestHandler](./kibana-plugin-core-server.requesthandler.md) execution. |
-|  [namespaceIdToString](./kibana-plugin-core-server.namespaceidtostring.md) | Converts a given saved object namespace ID to its string representation. All namespace IDs have an identical string representation, with the exception of the <code>undefined</code> namespace ID (which has a namespace string of <code>'default'</code>). |
-|  [namespaceStringToId](./kibana-plugin-core-server.namespacestringtoid.md) | Converts a given saved object namespace string to its ID representation. All namespace strings have an identical ID representation, with the exception of the <code>'default'</code> namespace string (which has a namespace ID of <code>undefined</code>). |
 |  [ServiceStatusLevels](./kibana-plugin-core-server.servicestatuslevels.md) | The current "level" of availability of a service. |
 |  [validBodyOutput](./kibana-plugin-core-server.validbodyoutput.md) | The set of valid body.output |
 

src/core/server/index.ts

@@ -303,8 +303,6 @@ export {
   exportSavedObjectsToStream,
   importSavedObjectsFromStream,
   resolveSavedObjectsImportErrors,
-  namespaceIdToString,
-  namespaceStringToId,
 } from './saved_objects';
 
 export {

src/core/server/saved_objects/service/index.ts

@@ -58,8 +58,6 @@ export {
   SavedObjectsErrorHelpers,
   SavedObjectsClientFactory,
   SavedObjectsClientFactoryProvider,
-  namespaceIdToString,
-  namespaceStringToId,
 } from './lib';
 
 export * from './saved_objects_client';

src/core/server/saved_objects/service/lib/index.ts

@@ -30,5 +30,3 @@ export {
 } from './scoped_client_provider';
 
 export { SavedObjectsErrorHelpers } from './errors';
-
-export { namespaceIdToString, namespaceStringToId } from './namespace';

src/core/server/server.api.md

@@ -1596,12 +1596,6 @@ export function modifyUrl(url: string, urlModifier: (urlParts: URLMeaningfulPart
 // @public
 export type MutatingOperationRefreshSetting = boolean | 'wait_for';
 
-// @public
-export const namespaceIdToString: (namespace?: string | undefined) => string;
-
-// @public
-export const namespaceStringToId: (namespace: string) => string | undefined;
-
 // Warning: (ae-missing-release-tag) "NodesVersionCompatibility" is exported by the package, but it is missing a release tag (@alpha, @beta, @public, or @internal)
 //
 // @public (undocumented)

x-pack/plugins/spaces/server/lib/copy_to_spaces/copy_to_spaces.test.ts

@@ -20,7 +20,6 @@ import { copySavedObjectsToSpacesFactory } from './copy_to_spaces';
 
 jest.mock('../../../../../../src/core/server', () => {
   return {
-    ...(jest.requireActual('../../../../../../src/core/server') as Record<string, unknown>),
     exportSavedObjectsToStream: jest.fn(),
     importSavedObjectsFromStream: jest.fn(),
   };

x-pack/plugins/spaces/server/lib/copy_to_spaces/resolve_copy_conflicts.test.ts

@@ -20,7 +20,6 @@ import { resolveCopySavedObjectsToSpacesConflictsFactory } from './resolve_copy_
 
 jest.mock('../../../../../../src/core/server', () => {
   return {
-    ...(jest.requireActual('../../../../../../src/core/server') as Record<string, unknown>),
     exportSavedObjectsToStream: jest.fn(),
     resolveSavedObjectsImportErrors: jest.fn(),
   };

x-pack/plugins/spaces/server/lib/utils/namespace.test.ts

@@ -4,29 +4,45 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { mockNamespaceIdToString, mockNamespaceStringToId } from './__mocks__';
+import { DEFAULT_SPACE_ID } from '../../../common/constants';
 import { spaceIdToNamespace, namespaceToSpaceId } from './namespace';
 
-beforeEach(() => {
-  jest.clearAllMocks();
-});
-
 describe('#spaceIdToNamespace', () => {
-  it('returns result of namespaceStringToId', () => {
-    mockNamespaceStringToId.mockReturnValue('bar');
+  it('converts the default space to undefined', () => {
+    expect(spaceIdToNamespace(DEFAULT_SPACE_ID)).toBeUndefined();
+  });
+
+  it('returns non-default spaces as-is', () => {
+    expect(spaceIdToNamespace('foo')).toEqual('foo');
+  });
 
-    const result = spaceIdToNamespace('foo');
-    expect(mockNamespaceStringToId).toHaveBeenCalledWith('foo');
-    expect(result).toEqual('bar');
+  it('throws an error when a spaceId is not provided', () => {
+    // @ts-ignore ts knows this isn't right
+    expect(() => spaceIdToNamespace()).toThrowErrorMatchingInlineSnapshot(`"spaceId is required"`);
+
+    // @ts-ignore ts knows this isn't right
+    expect(() => spaceIdToNamespace(null)).toThrowErrorMatchingInlineSnapshot(
+      `"spaceId is required"`
+    );
+
+    expect(() => spaceIdToNamespace('')).toThrowErrorMatchingInlineSnapshot(
+      `"spaceId is required"`
+    );
   });
 });
 
 describe('#namespaceToSpaceId', () => {
-  it('returns result of namespaceIdToString', () => {
-    mockNamespaceIdToString.mockReturnValue('bar');
+  it('returns the default space id for undefined namespaces', () => {
+    expect(namespaceToSpaceId(undefined)).toEqual(DEFAULT_SPACE_ID);
+  });
+
+  it('returns all other namespaces as-is', () => {
+    expect(namespaceToSpaceId('foo')).toEqual('foo');
+  });
 
-    const result = namespaceToSpaceId('foo');
-    expect(mockNamespaceIdToString).toHaveBeenCalledWith('foo');
-    expect(result).toEqual('bar');
+  it('throws an error when an empty string is provided', () => {
+    expect(() => namespaceToSpaceId('')).toThrowErrorMatchingInlineSnapshot(
+      `"namespace cannot be an empty string"`
+    );
   });
 });

x-pack/plugins/spaces/server/lib/utils/namespace.ts

@@ -4,22 +4,28 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { namespaceStringToId, namespaceIdToString } from '../../../../../../src/core/server';
+import { DEFAULT_SPACE_ID } from '../../../common/constants';
 
-/**
- * Converts a Space ID string to its namespace ID representation. Note that a Space ID string is equivalent to a namespace string.
- *
- * See also: {@link namespaceStringToId}.
- */
-export function spaceIdToNamespace(spaceId: string) {
-  return namespaceStringToId(spaceId);
+export function spaceIdToNamespace(spaceId: string): string | undefined {
+  if (!spaceId) {
+    throw new TypeError('spaceId is required');
+  }
+
+  if (spaceId === DEFAULT_SPACE_ID) {
+    return undefined;
+  }
+
+  return spaceId;
 }
 
-/**
- * Converts a namespace ID to its Space ID string representation. Note that a Space ID string is equivalent to a namespace string.
- *
- * See also: {@link namespaceIdToString}.
- */
-export function namespaceToSpaceId(namespace?: string) {
-  return namespaceIdToString(namespace);
+export function namespaceToSpaceId(namespace: string | undefined): string {
+  if (namespace === '') {
+    throw new TypeError('namespace cannot be an empty string');
+  }
+
+  if (!namespace) {
+    return DEFAULT_SPACE_ID;
+  }
+
+  return namespace;
 }

x-pack/plugins/spaces/server/routes/api/external/copy_to_space.test.ts

@@ -30,10 +30,10 @@ import { securityMock } from '../../../../../security/server/mocks';
 import { ObjectType } from '@kbn/config-schema';
 jest.mock('../../../../../../../src/core/server', () => {
   return {
-    ...(jest.requireActual('../../../../../../../src/core/server') as Record<string, unknown>),
     exportSavedObjectsToStream: jest.fn(),
     importSavedObjectsFromStream: jest.fn(),
     resolveSavedObjectsImportErrors: jest.fn(),
+    kibanaResponseFactory: jest.requireActual('src/core/server').kibanaResponseFactory,
   };
 });
 import {