fix(codegen): read react-native.config.cjs so ESM projects are not silently skipped

packages/react-native/scripts/codegen/__tests__/generate-artifacts-executor-test.js

@@ -21,6 +21,7 @@ const {
 const {
   cleanupEmptyFilesAndFolders,
   extractLibrariesFromJSON,
+  readReactNativeConfig,
 } = require('../generate-artifacts-executor/utils');
 const fs = require('node:fs');
 const os = require('node:os');
@@ -142,6 +143,58 @@ const packageJson = JSON.stringify({
   });
 });
 
+describe('readReactNativeConfig', () => {
+  const CONFIG_JS = "module.exports = {dependencies: {'from-js': {root: '/js'}}};";
+  const CONFIG_CJS = "module.exports = {dependencies: {'from-cjs': {root: '/cjs'}}};";
+
+  function withProjectRoot(files, assertion) {
+    const projectRoot = fs.mkdtempSync(
+      path.join(os.tmpdir(), 'react-native-codegen-config-'),
+    );
+    try {
+      for (const [name, contents] of Object.entries(files)) {
+        fs.writeFileSync(path.join(projectRoot, name), contents);
+      }
+      // baseOutputPath is a directory with no generated autolinking output, so
+      // resolution falls through to the react-native.config file.
+      assertion(readReactNativeConfig(projectRoot, projectRoot));
+    } finally {
+      fs.rmSync(projectRoot, {recursive: true, force: true});
+    }
+  }
+
+  it('reads react-native.config.js', () => {
+    withProjectRoot({'react-native.config.js': CONFIG_JS}, config => {
+      expect(config.dependencies).toHaveProperty('from-js');
+    });
+  });
+
+  it('reads react-native.config.cjs when there is no .js config', () => {
+    withProjectRoot({'react-native.config.cjs': CONFIG_CJS}, config => {
+      expect(config.dependencies).toHaveProperty('from-cjs');
+    });
+  });
+
+  it('prefers react-native.config.js when both exist', () => {
+    withProjectRoot(
+      {
+        'react-native.config.js': CONFIG_JS,
+        'react-native.config.cjs': CONFIG_CJS,
+      },
+      config => {
+        expect(config.dependencies).toHaveProperty('from-js');
+        expect(config.dependencies).not.toHaveProperty('from-cjs');
+      },
+    );
+  });
+
+  it('returns an empty config when neither exists', () => {
+    withProjectRoot({}, config => {
+      expect(config).toEqual({});
+    });
+  });
+});
+
 describe('extractSupportedApplePlatforms', () => {
   it('extracts platforms when podspec specifies object of platforms', () => {
     const myDependency = 'test-library';

packages/react-native/scripts/codegen/generate-artifacts-executor/utils.js

@@ -126,14 +126,16 @@ function readReactNativeConfig(
     projectRoot,
     baseOutputPath,
   );
-  const rnConfigFilePath = path.resolve(projectRoot, 'react-native.config.js');
+  const rnConfigFilePath = ['react-native.config.js', 'react-native.config.cjs']
+    .map(fileName => path.resolve(projectRoot, fileName))
+    .find(candidatePath => fs.existsSync(candidatePath));
   if (autolinkingOutput) {
     return autolinkingOutput;
-  } else if (fs.existsSync(rnConfigFilePath)) {
+  } else if (rnConfigFilePath != null) {
     // $FlowFixMe[unsupported-syntax]
     return require(rnConfigFilePath);
   } else {
-    codegenLog(`Could not find React Native config at: ${rnConfigFilePath}`);
+    codegenLog(`Could not find React Native config in: ${projectRoot}`);
     return {};
   }
 }