fix(link-assets): match asset extensions case-insensitively

packages/cli-link-assets/src/__tests__/linkAssets.test.ts

@@ -585,4 +585,59 @@ describe('linkAssets', () => {
       ),
     ).toMatchSnapshot();
   });
+  it('should link a font asset whose extension is upper-cased', async () => {
+    writeFiles(DIR, {
+      ...baseProjectKotlin,
+      'assets/shared/fonts/Montserrat-Regular.TTF':
+        fixtureFiles.montserratRegularFont,
+    });
+
+    await linkAssets([], configMock as CLIConfig);
+
+    // Android: it is linked as a font resource, not as a custom asset.
+    expect(readMontserratXMLFontFile()).toContain('@font/montserrat_regular');
+    expect(
+      fs.existsSync(
+        path.resolve(
+          DIR,
+          'android/app/src/main/res/font/montserrat_regular.ttf',
+        ),
+      ),
+    ).toBe(true);
+    expect(
+      fs.existsSync(
+        path.resolve(
+          DIR,
+          'android/app/src/main/assets/custom/Montserrat-Regular.TTF',
+        ),
+      ),
+    ).toBe(false);
+    expect(readMainApplicationKotlinFile()).toContain(
+      'addCustomFont(this, "Montserrat", R.font.montserrat)',
+    );
+
+    // iOS: it is registered in `UIAppFonts`, otherwise the font ships in the
+    // bundle but cannot be used at runtime.
+    expect(readInfoPlistFile()).toContain('Montserrat-Regular.TTF');
+  });
+
+  it('should link an image asset whose extension is upper-cased', async () => {
+    writeFiles(DIR, {
+      ...baseProjectKotlin,
+      'assets/shared/Upper Image.PNG': fixtureFiles.imagePng,
+    });
+
+    await linkAssets([], configMock as CLIConfig);
+
+    expect(
+      fs.existsSync(
+        path.resolve(DIR, 'android/app/src/main/res/drawable/upper_image.png'),
+      ),
+    ).toBe(true);
+    expect(
+      fs.existsSync(
+        path.resolve(DIR, 'android/app/src/main/assets/custom/Upper Image.PNG'),
+      ),
+    ).toBe(false);
+  });
 });

packages/cli-link-assets/src/fileTypes.ts

@@ -1,7 +1,20 @@
+import path from 'path';
+
 const fontTypes = ['otf', 'ttf'] as const;
 
 const imageTypes = ['png', 'jpg', 'gif'] as const;
 
 const audioTypes = ['mp3'] as const;
 
-export {fontTypes, imageTypes, audioTypes};
+/**
+ * Returns the extension of an asset, without the leading dot and lower-cased.
+ *
+ * The known asset types above are all spelled in lower case, while the
+ * extension on disk can be cased in any way (`Lato-Regular.TTF`), so it has to
+ * be normalized before it is matched against them.
+ */
+function getAssetExtension(filePath: string) {
+  return path.extname(filePath).substring(1).toLowerCase();
+}
+
+export {fontTypes, imageTypes, audioTypes, getAssetExtension};

packages/cli-link-assets/src/tools/linkPlatform/index.ts

@@ -1,6 +1,7 @@
 import {CLIError, logger} from '@react-native-community/cli-tools';
 import fs from 'fs';
 import path from 'path';
+import {getAssetExtension} from '../../fileTypes';
 import sha1File from '../../sha1File';
 import {CleanAssets} from '../cleanAssets/types';
 import {CopyAssets} from '../copyAssets/types';
@@ -173,15 +174,15 @@ function linkPlatform({
     .map((fileExt): FileFilter => {
       return {
         name: fileExt,
-        filter: (asset) => path.extname(asset.path) === `.${fileExt}`,
+        filter: (asset) => getAssetExtension(asset.path) === fileExt,
         options: linkOptionsPerExt[fileExt as Extension],
       };
     })
     .concat({
       name: 'custom',
       filter: (asset) =>
         Object.keys(linkOptionsPerExt).indexOf(
-          path.extname(asset.path).substring(1),
+          getAssetExtension(asset.path),
         ) === -1,
       options: otherLinkOptions,
     });

packages/cli-link-assets/src/tools/manifest/migrations/migration2.ts

@@ -1,6 +1,5 @@
-import path from 'path';
 import {AssetPathAndSHA1} from '..';
-import {fontTypes} from '../../../fileTypes';
+import {fontTypes, getAssetExtension} from '../../../fileTypes';
 import {Platform} from '../../linkPlatform';
 
 function migration2(
@@ -12,7 +11,7 @@ function migration2(
     shouldRelinkAndroidFonts:
       platform === 'android' &&
       fontTypes.includes(
-        path.extname(asset.path).substring(1) as (typeof fontTypes)[number],
+        getAssetExtension(asset.path) as (typeof fontTypes)[number],
       ),
   }));
 }