CLI: Warn the user when stories glob does not match any file

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

@@ -11,7 +11,7 @@ import { normalizeStoriesEntry } from '@storybook/core-common';
 import type { NormalizedStoriesSpecifier, StoryIndexer, StoryIndexEntry } from '@storybook/types';
 import { loadCsf, getStorySortParameter } from '@storybook/csf-tools';
 import { toId } from '@storybook/csf';
-import { logger } from '@storybook/node-logger';
+import { logger, once } from '@storybook/node-logger';
 
 import { StoryIndexGenerator } from './StoryIndexGenerator';
 
@@ -61,6 +61,7 @@ describe('StoryIndexGenerator', () => {
     const actual = jest.requireActual('@storybook/csf-tools');
     loadCsfMock.mockImplementation(actual.loadCsf);
     jest.mocked(logger.warn).mockClear();
+    jest.mocked(once.warn).mockClear();
   });
   describe('extraction', () => {
     const storiesSpecifier: NormalizedStoriesSpecifier = normalizeStoriesEntry(
@@ -925,6 +926,21 @@ describe('StoryIndexGenerator', () => {
       });
     });
 
+    describe('warnings', () => {
+      it('when entries do not match any files', async () => {
+        const generator = new StoryIndexGenerator(
+          [normalizeStoriesEntry('./src/docs2/wrong.js', options)],
+          options
+        );
+        await generator.initialize();
+        await generator.getIndex();
+
+        expect(once.warn).toHaveBeenCalledTimes(1);
+        const logMessage = jest.mocked(once.warn).mock.calls[0][0];
+        expect(logMessage).toContain(`No story files found for the specified pattern`);
+      });
+    });
+
     describe('duplicates', () => {
       it('warns when two MDX entries reference the same CSF file without a name', async () => {
         const docsErrorSpecifier: NormalizedStoriesSpecifier = normalizeStoriesEntry(

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

@@ -21,7 +21,7 @@ import type {
 } from '@storybook/types';
 import { userOrAutoTitleFromSpecifier, sortStoriesV7 } from '@storybook/preview-api';
 import { normalizeStoryPath } from '@storybook/core-common';
-import { logger } from '@storybook/node-logger';
+import { logger, once } from '@storybook/node-logger';
 import { getStorySortParameter } from '@storybook/csf-tools';
 import { toId } from '@storybook/csf';
 import { analyze } from '@storybook/docs-mdx';
@@ -122,6 +122,15 @@ export class StoryIndexGenerator {
           path.join(this.options.workingDir, specifier.directory, specifier.files)
         );
         const files = await glob(fullGlob);
+
+        if (files.length === 0) {
+          once.warn(
+            `No story files found for the specified pattern: ${chalk.blue(
+              path.join(specifier.directory, specifier.files)
+            )}`
+          );
+        }
+
         files.sort().forEach((absolutePath: Path) => {
           const ext = path.extname(absolutePath);
           if (ext === '.storyshot') {