Sdk path should be used when launching emulator

Summary:
Changelog: Fixed issue where a missing ANDROID_SDK_ROOT env var made it impossible to launch emulators

Run into an issue where ANDROID_SDK_ROOT wasn't set for my user, causing Flipper not to be able to launch emulator, which was looked up from the path rather than using the flipper settings.

Fixes: https://github.com/facebook/flipper/issues/3119

Reviewed By: timur-valiev

Differential Revision: D33158280

fbshipit-source-id: ea5616b10265ed43f1012c58da081be275ff1d5b

desktop/app/src/init.tsx

@@ -204,6 +204,7 @@ function setProcessState(settings: Settings) {
 
   if (!process.env.ANDROID_HOME && !process.env.ANDROID_SDK_ROOT) {
     process.env.ANDROID_HOME = androidHome;
+    process.env.ANDROID_SDK_ROOT = androidHome;
   }
 
   // emulator/emulator is more reliable than tools/emulator, so prefer it if

desktop/flipper-server-core/src/FlipperServerImpl.tsx

@@ -337,7 +337,7 @@ export class FlipperServerImpl implements FlipperServer {
     },
     'android-get-emulators': async () => this.android.getAndroidEmulators(),
     'android-launch-emulator': async (name, coldBoot) =>
-      launchEmulator(name, coldBoot),
+      launchEmulator(this.config.settings.androidHome, name, coldBoot),
     'ios-get-simulators': async (bootedOnly) =>
       this.ios.getSimulators(bootedOnly),
     'ios-launch-simulator': async (udid) => launchSimulator(udid),

desktop/flipper-server-core/src/devices/android/AndroidDevice.tsx

@@ -276,34 +276,32 @@ export default class AndroidDevice extends ServerDevice {
   }
 }
 
-export async function launchEmulator(name: string, coldBoot: boolean = false) {
+export async function launchEmulator(
+  androidHome: string,
+  name: string,
+  coldBoot: boolean = false,
+) {
+  try {
     // On Linux, you must run the emulator from the directory it's in because
     // reasons ...
-  return which('emulator')
-    .catch(() =>
-      join(
-        process.env.ANDROID_HOME || process.env.ANDROID_SDK_ROOT || '',
-        'emulator',
-        'emulator',
-      ),
-    )
-    .then((emulatorPath) => {
-      if (emulatorPath) {
+    const emulatorPath = join(androidHome, 'emulator', 'emulator');
     const child = spawn(
       emulatorPath,
       [`@${name}`, ...(coldBoot ? ['-no-snapshot-load'] : [])],
       {
         detached: true,
         cwd: dirname(emulatorPath),
+        env: {
+          ...process.env,
+          ANDROID_SDK_ROOT: androidHome,
+        },
       },
     );
     child.stderr.on('data', (data) => {
       console.warn(`Android emulator stderr: ${data}`);
     });
     child.on('error', (e) => console.warn('Android emulator error:', e));
-      } else {
-        throw new Error('Could not get emulator path');
+  } catch (e) {
+    console.warn('Android emulator startup failed:', e);
   }
-    })
-    .catch((e) => console.error('Android emulator startup failed:', e));
 }

desktop/flipper-server-core/src/devices/android/androidDeviceManager.tsx

@@ -23,9 +23,6 @@ import {
 } from '../../FlipperServerConfig';
 
 export class AndroidDeviceManager {
-  // cache emulator path
-  private emulatorPath: string | undefined;
-
   constructor(public flipperServer: FlipperServerImpl) {}
 
   private createDevice(
@@ -119,25 +116,16 @@ export class AndroidDeviceManager {
     });
   }
 
-  async getEmulatorPath(): Promise<string> {
-    if (this.emulatorPath) {
-      return this.emulatorPath;
-    }
-    // TODO: this doesn't respect the currently configured android_home in settings!
-    try {
-      this.emulatorPath = (await promisify(which)('emulator')) as string;
-    } catch (_e) {
-      this.emulatorPath = join(
-        process.env.ANDROID_HOME || process.env.ANDROID_SDK_ROOT || '',
+  getEmulatorPath(): string {
+    return join(
+      this.flipperServer.config.settings.androidHome,
       'emulator',
       'emulator',
     );
   }
-    return this.emulatorPath;
-  }
 
   async getAndroidEmulators(): Promise<string[]> {
-    const emulatorPath = await this.getEmulatorPath();
+    const emulatorPath = this.getEmulatorPath();
     return new Promise<string[]>((resolve) => {
       child_process.execFile(
         emulatorPath as string,