Fix error message when there's no xcode-select'ed Xcode

Summary:
This error messaging is confusing for device only users. These users may only be running against a device **without xcode installed**, which is supported.

However, we also need to handle the case where a user has a sim running and they haven't xcode-select'd as this will mean that the sim is working fine, but the user has no way of knowing why Flipper is not working.

Reviewed By: passy

Differential Revision: D34140277

fbshipit-source-id: f9b035b6c7918424d6131d1dfcdba10acf438fa8

desktop/flipper-server-core/src/devices/ios/__tests__/iOSDevice.node.tsx

@@ -75,6 +75,14 @@ test('test checkXcodeVersionMismatch with correct Simulator.app', () => {
   expect(invalidVersion).toEqual(undefined);
 });
 
+test('test checkXcodeVersionMismatch with no running Simulator.app', () => {
+  const invalidVersion = checkXcodeVersionMismatch(
+    [],
+    '/Applications/Xcode.app/Contents/Developer',
+  );
+  expect(invalidVersion).toEqual(undefined);
+});
+
 test('test checkXcodeVersionMismatch with an incorrect Simulator.app', () => {
   const invalidVersion = checkXcodeVersionMismatch(
     [
@@ -82,11 +90,31 @@ test('test checkXcodeVersionMismatch with an incorrect Simulator.app', () => {
     ],
     '/Applications/Xcode.app/Contents/Developer',
   );
-  expect(invalidVersion).toEqual(
+  expect(invalidVersion).toContain(
     '/Applications/Xcode_Incorrect.app/Contents/Developer',
   );
 });
 
+test('test checkXcodeVersionMismatch with no sims running and no xcode-select', () => {
+  const invalidVersion = checkXcodeVersionMismatch(
+    [],
+    '/Library/Developer/CommandLineTools',
+  );
+  expect(invalidVersion).toEqual(undefined);
+});
+
+test('test checkXcodeVersionMismatch with no sims running and no xcode-select', () => {
+  const invalidVersion = checkXcodeVersionMismatch(
+    [
+      '/Applications/Xcode.app/Contents/Developer/Applications/Simulator.app/Contents/MacOS/Simulator',
+    ],
+    '/Library/Developer/CommandLineTools',
+  );
+  expect(invalidVersion).toContain(
+    'A Simulator is running and "xcode-select" has not been used',
+  );
+});
+
 test('test queryDevices when simctl used', async () => {
   const ios = new IOSDeviceManager(
     fakeFlipperServer,

desktop/flipper-server-core/src/devices/ios/iOSDeviceManager.tsx

@@ -204,18 +204,17 @@ export class IOSDeviceManager {
         .toString()
         .split('\n')
         .filter((application) => application.length > 0);
-      const mismatchedVersion = checkXcodeVersionMismatch(
+      const errorMessage = checkXcodeVersionMismatch(
         runningSimulatorApplications,
         xcodeCLIVersion,
       );
-      if (mismatchedVersion === undefined) {
+      if (errorMessage === undefined) {
         return;
       }
-      const errorMessage = `Xcode version mismatch: Simulator is running from "${mismatchedVersion}" while Xcode CLI is "${xcodeCLIVersion}". Running "xcode-select --switch ${xcodeCLIVersion}" can fix this. For example: "sudo xcode-select -s /Applications/Xcode.app/Contents/Developer"`;
       this.flipperServer.emit('notification', {
         type: 'error',
         title: 'Xcode version mismatch',
-        description: '' + errorMessage,
+        description: errorMessage,
       });
     } catch (e) {
       console.error('Failed to determine Xcode version:', e);
@@ -223,7 +222,7 @@ export class IOSDeviceManager {
   }
 }
 
-export function checkXcodeVersionMismatch(
+function confirmSimulatorAppMatchesThatOfXcodeSelect(
   runningSimulatorApps: Array<string>,
   xcodeCLIVersion: string,
 ): string | undefined {
@@ -241,3 +240,23 @@ export function checkXcodeVersionMismatch(
   }
   return undefined;
 }
+
+export function checkXcodeVersionMismatch(
+  runningSimulatorApps: Array<string>,
+  xcodeCLIVersion: string,
+): string | undefined {
+  if (runningSimulatorApps.length === 0) {
+    return undefined;
+  }
+  if (xcodeCLIVersion == '/Library/Developer/CommandLineTools') {
+    return `A Simulator is running and "xcode-select" has not been used, please run "xcode-select" for the Xcode that is running the simulator at ${runningSimulatorApps}`;
+  }
+  const mismatchedVersion = confirmSimulatorAppMatchesThatOfXcodeSelect(
+    runningSimulatorApps,
+    xcodeCLIVersion,
+  );
+  if (mismatchedVersion === undefined) {
+    return;
+  }
+  return `Xcode version mismatch: Simulator is running from "${mismatchedVersion}" while Xcode CLI is "${xcodeCLIVersion}". Running "xcode-select --switch ${xcodeCLIVersion}" can fix this. For example: "sudo xcode-select -s /Applications/Xcode.app/Contents/Developer"`;
+}