build: patch codegen and ensure android builds correctly

android/build.gradle

@@ -113,7 +113,7 @@ android {
       main {
         if (isNewArchitectureEnabled()) {
           java.srcDirs += ['src/newarch']
-          java.srcDirs += ['src/codegen']
+          java.srcDirs += ['src/codegen/java']
         } else {
           java.srcDirs += ['src/oldarch']
         }

package.json

@@ -69,9 +69,7 @@
     "build": "genversion --es6 --semi src/version.ts && bob build && yarn codegen",
     "build:clean": "rimraf android/build && rimraf ios/build && rimraf lib && rimraf plugin/build",
     "build:plugin": "yarn tsc --build plugin",
-    "codegen": "yarn codegen:android && yarn codegen:ios",
-    "codegen:android": "npx --yes @react-native-community/cli codegen --platform android --outputPath android/src/codegen",
-    "codegen:ios": "npx --yes @react-native-community/cli codegen --platform ios --outputPath ios/RNGoogleMobileAdsSpec",
+    "codegen": "npx --yes @react-native-community/cli codegen && node scripts/patch-codegen.mjs",
     "lint:code": "yarn lint:js && yarn lint:android && yarn lint:ios:check",
     "lint:js": "eslint src/ --ext .js,.jsx,.ts,.tsx --max-warnings=0",
     "lint:android": "google-java-format --set-exit-if-changed --replace --glob=\"android/src/main/**/*.java\"",
@@ -144,6 +142,7 @@
     "eslint-plugin-react": "^7.31.10",
     "expo": "^47.0.0",
     "expo-module-scripts": "^3.5.2",
+    "fs-extra": "^11.2.0",
     "genversion": "^3.1.1",
     "google-java-format": "^1.1.0",
     "jest": "^29.2.2",
@@ -172,6 +171,10 @@
     "name": "RNGoogleMobileAdsSpec",
     "type": "all",
     "jsSrcsDir": "./src/specs",
+    "outputDir": {
+      "android": "./android/src/codegen",
+      "ios": "./ios/RNGoogleMobileAdsSpec"
+    },
     "includesGeneratedCode": true,
     "android": {
       "javaPackageName": "io.invertase.googlemobileads"

scripts/patch-codegen.mjs

@@ -0,0 +1,83 @@
+import fs from 'fs-extra';
+import path from 'node:path';
+
+/**
+ * Currently, running react-native codegen generates java files with package name `com.facebook.fbreact.specs`.
+ * This is a known issue in react-native itself.
+ * You can find the relevant line here: https://github.com/facebook/react-native/blob/dc460147bb00d6f912cc0a829f8040d85faeeb13/packages/react-native/scripts/codegen/generate-artifacts-executor.js#L459.
+ * To workaround, this function renames the package name to the one provided in the codegenConfig.
+ * @throws if codegenConfig.outputDir.android or codegenConfig.android.javaPackageName is not defined in package.json
+ * @throws if the codegenAndroidPath does not exist
+ */
+async function patchCodegen() {
+  const projectPath = path.resolve(import.meta.dirname, '..');
+  const packageJsonPath = path.resolve(projectPath, 'package.json');
+  const packageJson = await fs.readJson(packageJsonPath);
+
+  let codegenAndroidPath = packageJson.codegenConfig.outputDir.android;
+  if (!codegenAndroidPath) {
+    throw new Error('You need to define codegenConfig.outputDir.android in your package.json');
+  }
+  codegenAndroidPath = path.resolve(projectPath, codegenAndroidPath);
+
+  if (!(await fs.pathExists(codegenAndroidPath))) {
+    throw new Error(
+      `Could not find ${codegenAndroidPath}. Make sure you are in the correct directory and react-native codegen works properly.`,
+    );
+  }
+
+  const codegenJavaPackageName = packageJson.codegenConfig.android.javaPackageName;
+  if (!codegenJavaPackageName) {
+    throw new Error(
+      'You need to define codegenConfig.android.javaPackageName in your package.json',
+    );
+  }
+
+  const codegenJavaPath = path.resolve(codegenAndroidPath, `java/com/facebook/fbreact/specs`);
+
+  // If this issue is ever fixed in react-native, this check will prevent the patching from running.
+  if (!(await fs.pathExists(codegenJavaPath))) {
+    console.log(`Could not find ${codegenJavaPath}. Skipping patching codegen java files.`);
+    return;
+  }
+
+  const javaFiles = await fs.readdir(codegenJavaPath);
+
+  await Promise.all(
+    javaFiles.map(async file => {
+      const filePath = path.resolve(codegenJavaPath, file);
+      const fileContent = await fs.readFile(filePath, 'utf8');
+
+      const newFileContent = fileContent.replace(
+        'package com.facebook.fbreact.specs',
+        `package ${codegenJavaPackageName}`,
+      );
+
+      await fs.writeFile(filePath, newFileContent);
+    }),
+  );
+
+  const newPackagePath = path.resolve(
+    codegenAndroidPath,
+    `java/${codegenJavaPackageName.replace(/\./g, '/')}`,
+  );
+
+  if (!(await fs.pathExists(newPackagePath))) {
+    await fs.mkdir(newPackagePath, { recursive: true });
+  }
+
+  await Promise.all(
+    javaFiles.map(async file => {
+      const filePath = path.resolve(codegenJavaPath, file);
+      const newFilePath = path.resolve(newPackagePath, file);
+
+      await fs.rename(filePath, newFilePath);
+    }),
+  );
+
+  await fs.rm(path.resolve(codegenAndroidPath, 'java/com/facebook/fbreact'), {
+    recursive: true,
+  });
+}
+
+patchCodegen();

yarn.lock

@@ -6537,7 +6537,7 @@ fs-extra@^10.1.0:
     jsonfile "^6.0.1"
     universalify "^2.0.0"
 
-fs-extra@^11.0.0:
+fs-extra@^11.0.0, fs-extra@^11.2.0:
   version "11.2.0"
   resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-11.2.0.tgz#e70e17dfad64232287d01929399e0ea7c86b0e5b"
   integrity sha512-PmDi3uwK5nFuXh7XDTlVnS17xJS7vW36is2+w3xcv8SVxiB4NyATf4ctkVY5bkSjX0Y4nbvZCq1/EjtEyr9ktw==