fix runIOS: appPath is hardcoded, read from log

Summary:
The runIOS command currently assumes the path to the `xcodebuild` product - it's hardcoded

```
  const appPath = `build/Build/Products/Debug-iphonesimulator/${inferredSchemeName}.app`;
```
https://github.com/facebook/react-native/blob/master/local-cli/runIOS/runIOS.js#L87

This can be a problem, when you e.g. install a release version of the app to the simulator using the cli. We use a separate schema for that, which can be selected with `--scheme`.

This fix reads the output of the `xcodebuild` call and searches for the path and the name of the *.app file. If it's found, then it will be used to spawn in the simulator. If not, the default (as before) is used.
Closes https://github.com/facebook/react-native/pull/8250

Differential Revision: D3469074

Pulled By: javache

fbshipit-source-id: b10c7e6f48268b0c71dfcbfa661f8e5960c3aaa6

local-cli/runIOS/runIOS.js

@@ -22,7 +22,6 @@ const Promise = require('promise');
 function runIOS(argv, config) {
   return new Promise((resolve, reject) => {
     _runIOS(argv, config, resolve, reject);
-    resolve();
   });
 }
 
@@ -51,7 +50,7 @@ function _runIOS(argv, config, resolve, reject) {
   process.chdir(args['project-path']);
   const xcodeProject = findXcodeProject(fs.readdirSync('.'));
   if (!xcodeProject) {
-    throw new Error(`Could not find Xcode project files in ios folder`);
+    reject(new Error(`Could not find Xcode project files in ios folder`));
   }
 
   const inferredSchemeName = path.basename(xcodeProject.name, path.extname(xcodeProject.name));
@@ -63,7 +62,7 @@ function _runIOS(argv, config, resolve, reject) {
   );
   const selectedSimulator = matchingSimulator(simulators, args.simulator);
   if (!selectedSimulator) {
-    throw new Error(`Cound't find ${args.simulator} simulator`);
+    reject(new Error(`Cound't find ${args.simulator} simulator`));
   }
 
   const simulatorFullName = `${selectedSimulator.name} (${selectedSimulator.version})`;
@@ -82,9 +81,28 @@ function _runIOS(argv, config, resolve, reject) {
     '-derivedDataPath', 'build',
   ];
   console.log(`Building using "xcodebuild ${xcodebuildArgs.join(' ')}"`);
-  child_process.spawnSync('xcodebuild', xcodebuildArgs, {stdio: 'inherit'});
 
-  const appPath = `build/Build/Products/Debug-iphonesimulator/${inferredSchemeName}.app`;
+  let appPath = `build/Build/Products/Debug-iphonesimulator/${inferredSchemeName}.app`;
+  const xcodeBuildProcess = child_process.spawn('xcodebuild', xcodebuildArgs, {
+    stdio: [process.stdin, 'pipe', process.stderr]
+  });
+
+  xcodeBuildProcess.stdout.on('data', (data) => {
+    process.stdout.write(data);
+
+    // search this part of the process output for a path to the generated app and replace default
+    const appPathFromLog = data.toString().match(/Touch (build\/Build\/Products\/.*\/.*\.app)/);
+    if (appPathFromLog) {
+      appPath = appPathFromLog[1];
+    }
+  });
+
+  xcodeBuildProcess.on('close', (code) => {
+    if (code !== 0) {
+      reject(new Error(`xcodebuild process exited with code ${code}`));
+      return;
+    }
+
     console.log(`Installing ${appPath}`);
     child_process.spawnSync('xcrun', ['simctl', 'install', 'booted', appPath], {stdio: 'inherit'});
 
@@ -96,6 +114,9 @@ function _runIOS(argv, config, resolve, reject) {
 
     console.log(`Launching ${bundleID}`);
     child_process.spawnSync('xcrun', ['simctl', 'launch', 'booted', bundleID], {stdio: 'inherit'});
+
+    resolve();
+  });
 }
 
 function matchingSimulator(simulators, simulatorName) {