Add test to prove #20864 is unneccesary

And set things up for #20863

code/lib/core-server/src/utils/StoryIndexGenerator.test.ts

@@ -463,25 +463,103 @@ describe('StoryIndexGenerator', () => {
         );
       });
 
-      it('throws an error if you attach a MetaOf entry to a tagged autodocs entry', async () => {
+      it('throws an error if you attach a named MetaOf entry which clashes with a tagged autodocs entry', async () => {
         const csfSpecifier: NormalizedStoriesSpecifier = normalizeStoriesEntry(
           './src/B.stories.ts',
           options
         );
 
         const docsSpecifier: NormalizedStoriesSpecifier = normalizeStoriesEntry(
-          './errors/MetaOfAutodocs.mdx',
+          './errors/MetaOfClashingDefaultName.mdx',
           options
         );
 
         const generator = new StoryIndexGenerator([csfSpecifier, docsSpecifier], autodocsOptions);
         await generator.initialize();
 
         await expect(generator.getIndex()).rejects.toThrowError(
-          `You created a component docs page for B (./errors/MetaOfAutodocs.mdx), but also tagged the CSF file (./src/B.stories.ts) with 'autodocs'. This is probably a mistake.`
+          `You created a component docs page for B (./errors/MetaOfClashingDefaultName.mdx), but also tagged the CSF file (./src/B.stories.ts) with 'autodocs'. This is probably a mistake.`
         );
       });
 
+      it('throws an error if you attach a unnamed MetaOf entry which clashes with a tagged autodocs entry', async () => {
+        const csfSpecifier: NormalizedStoriesSpecifier = normalizeStoriesEntry(
+          './src/B.stories.ts',
+          options
+        );
+
+        const docsSpecifier: NormalizedStoriesSpecifier = normalizeStoriesEntry(
+          './errors/MetaOfNoName.mdx',
+          options
+        );
+
+        const generator = new StoryIndexGenerator([csfSpecifier, docsSpecifier], autodocsOptions);
+        await generator.initialize();
+
+        await expect(generator.getIndex()).rejects.toThrowError(
+          `You created a component docs page for B (./errors/MetaOfNoName.mdx), but also tagged the CSF file (./src/B.stories.ts) with 'autodocs'. This is probably a mistake.`
+        );
+      });
+
+      it('allows you to create a second MetaOf entry with a different name to autodocs', async () => {
+        const csfSpecifier: NormalizedStoriesSpecifier = normalizeStoriesEntry(
+          './src/B.stories.ts',
+          options
+        );
+
+        const docsSpecifier: NormalizedStoriesSpecifier = normalizeStoriesEntry(
+          './errors/MetaOfName.mdx',
+          options
+        );
+
+        const generator = new StoryIndexGenerator([csfSpecifier, docsSpecifier], autodocsOptions);
+        await generator.initialize();
+
+        expect(await generator.getIndex()).toMatchInlineSnapshot(`
+          Object {
+            "entries": Object {
+              "b--docs": Object {
+                "id": "b--docs",
+                "importPath": "./src/B.stories.ts",
+                "name": "docs",
+                "storiesImports": Array [],
+                "tags": Array [
+                  "autodocs",
+                  "docs",
+                ],
+                "title": "B",
+                "type": "docs",
+              },
+              "b--name": Object {
+                "id": "b--name",
+                "importPath": "./errors/MetaOfName.mdx",
+                "name": "name",
+                "storiesImports": Array [
+                  "./src/B.stories.ts",
+                ],
+                "tags": Array [
+                  "docs",
+                ],
+                "title": "B",
+                "type": "docs",
+              },
+              "b--story-one": Object {
+                "id": "b--story-one",
+                "importPath": "./src/B.stories.ts",
+                "name": "Story One",
+                "tags": Array [
+                  "autodocs",
+                  "story",
+                ],
+                "title": "B",
+                "type": "story",
+              },
+            },
+            "v": 4,
+          }
+        `);
+      });
+
       it('allows you to override autodocs with MetaOf if it is automatic', async () => {
         const csfSpecifier: NormalizedStoriesSpecifier = normalizeStoriesEntry(
           './src/A.stories.js',
@@ -829,7 +907,7 @@ describe('StoryIndexGenerator', () => {
     describe('duplicates', () => {
       it('warns when two MDX entries reference the same CSF file without a name', async () => {
         const docsErrorSpecifier: NormalizedStoriesSpecifier = normalizeStoriesEntry(
-          './errors/DuplicateMetaOf.mdx',
+          './errors/DuplicateMetaOfNoName.mdx',
           options
         );
 

code/lib/core-server/src/utils/__mockdata__/errors/MetaOfClashingDefaultName.mdx

@@ -0,0 +1,9 @@
+import * as BStories from '../src/B.stories';
+
+{/* This is the same name as the default name (i.e. autodocs entry) */}
+
+<Meta of={BStories} name="Docs" />
+
+# Docs with of
+
+hello docs

code/lib/core-server/src/utils/__mockdata__/errors/MetaOfName.mdx

@@ -0,0 +1,7 @@
+import * as BStories from '../src/B.stories';
+
+<Meta of={BStories} name="name" />
+
+# Docs with of
+
+hello docs