Fix `react-native link` issue when using multiple manifests

Summary:
`react-native link` often fails due to the wrong manifest being used when you use a debug manifest. `findManifest` returns `debug/AndroidManifest.xml` instead of `main/AndroidManifest.xml`. And the debug manifest usually does not have the package name defined so `projectConfigAndroid` throws a cryptic "Cannot read property 'replace' of undefined" error.

This fixes the issue by throwing a more user friendly error and providing a `manifestPath` userConfig.

This is mostly based on comments to #10050.
Closes https://github.com/facebook/react-native/pull/13373

Differential Revision: D4945690

Pulled By: shergin

fbshipit-source-id: b177f916fd4799c873d2515c18cbb87bef3203f0

local-cli/core/__fixtures__/android.js

@@ -20,6 +20,25 @@ exports.valid = {
   },
 };
 
+exports.userConfigManifest = {
+  src: {
+    main: {
+      'AndroidManifest.xml': manifest,
+      com: {
+        some: {
+          example: {
+            'Main.java': mainJavaClass,
+            'ReactPackage.java': fs.readFileSync(path.join(__dirname, './files/ReactPackage.java')),
+          },
+        },
+      },
+    },
+    debug: {
+      'AndroidManifest.xml': fs.readFileSync(path.join(__dirname, './files/AndroidManifest-debug.xml')),
+    },
+  },
+};
+
 exports.corrupted = {
   src: {
     'AndroidManifest.xml': manifest,

local-cli/core/__fixtures__/files/AndroidManifest-debug.xml

@@ -0,0 +1,3 @@
+<manifest
+  xmlns:android="http://schemas.android.com/apk/res/android">
+</manifest>

local-cli/core/__tests__/android/getProjectConfig.spec.js

@@ -15,6 +15,9 @@ describe('android::getProjectConfig', () => {
     flat: {
       android: mocks.valid,
     },
+    multiple: {
+      android: mocks.userConfigManifest,
+    },
     noManifest: {
       android: {},
     },
@@ -43,6 +46,16 @@ describe('android::getProjectConfig', () => {
       expect(getProjectConfig(folder, userConfig)).not.toBe(null);
       expect(typeof getProjectConfig(folder, userConfig)).toBe('object');
     });
+
+    it('multiple', () => {
+      const userConfig = {
+        manifestPath: 'src/main/AndroidManifest.xml'
+      };
+      const folder = 'multiple';
+
+      expect(getProjectConfig(folder, userConfig)).not.toBe(null);
+      expect(typeof getProjectConfig(folder, userConfig)).toBe('object');
+    });
   });
 
   it('should return `null` if android project was not found', () => {

local-cli/core/android/index.js

@@ -29,7 +29,9 @@ exports.projectConfig = function projectConfigAndroid(folder, userConfig) {
 
   const sourceDir = path.join(folder, src);
   const isFlat = sourceDir.indexOf('app') === -1;
-  const manifestPath = findManifest(sourceDir);
+  const manifestPath = userConfig.manifestPath
+    ? path.join(sourceDir, userConfig.manifestPath)
+    : findManifest(sourceDir);
 
   if (!manifestPath) {
     return null;
@@ -38,6 +40,11 @@ exports.projectConfig = function projectConfigAndroid(folder, userConfig) {
   const manifest = readManifest(manifestPath);
 
   const packageName = userConfig.packageName || getPackageName(manifest);
+
+  if (!packageName) {
+    throw new Error(`Package name not found in ${manifestPath}`);
+  }
+
   const packageFolder = userConfig.packageFolder ||
     packageName.replace(/\./g, path.sep);
 
@@ -92,7 +99,9 @@ exports.dependencyConfig = function dependencyConfigAndroid(folder, userConfig)
   }
 
   const sourceDir = path.join(folder, src);
-  const manifestPath = findManifest(sourceDir);
+  const manifestPath = userConfig.manifestPath
+    ? path.join(sourceDir, userConfig.manifestPath)
+    : findManifest(sourceDir);
 
   if (!manifestPath) {
     return null;