fix(ios): don't end device discovery on the wrong device

With 100 ms polling, an unrelated device ended the wait almost immediately. A requested device now only ends it by being found, and otherwise the 2 seconds the old polling allowed still apply, so device indexes stay stable.

Author: rigor789

lib/common/mobile/ios/device/ios-device-operations.ts

@@ -11,6 +11,22 @@ import {
 } from "../../../declarations";
 import { injector } from "../../../yok";
 
+// Other devices can still be arriving by then, and device indexes follow the
+// order they were discovered in.
+const MIN_DISCOVERY_WAIT_MS = 2000;
+
+export function isDeviceDiscoveryDone(
+	foundDevice: boolean,
+	waitedMs: number,
+	options?: Mobile.IDeviceLookingOptions,
+): boolean {
+	if (options?.isRequestedDeviceFound) {
+		return options.isRequestedDeviceFound();
+	}
+
+	return foundDevice && !options?.fullDiscovery && waitedMs >= MIN_DISCOVERY_WAIT_MS;
+}
+
 export class IOSDeviceOperations
 	extends EventEmitter
 	implements IIOSDeviceOperations, IDisposable, IShouldDispose
@@ -91,16 +107,11 @@ export class IOSDeviceOperations
 				let waited = 0;
 
 				const intervalHandle: NodeJS.Timer = setInterval(() => {
+					waited += pollInterval;
 					if (
-						(foundDevice && !options.fullDiscovery) ||
-						options.isRequestedDeviceFound?.()
+						waited >= maxWait ||
+						isDeviceDiscoveryDone(foundDevice, waited, options)
 					) {
-						resolve();
-						return clearInterval(intervalHandle as unknown as number);
-					}
-
-					waited += pollInterval;
-					if (waited >= maxWait) {
 						clearInterval(intervalHandle as unknown as number);
 						return resolve();
 					}

lib/common/test/unit-tests/mobile/ios-device-operations.ts

@@ -0,0 +1,39 @@
+import { assert } from "chai";
+import { isDeviceDiscoveryDone } from "../../../mobile/ios/device/ios-device-operations";
+
+describe("isDeviceDiscoveryDone", () => {
+	const options = (extra: object = {}) => <any>{ ...extra };
+
+	it("ends as soon as the requested device is found", () => {
+		const isRequestedDeviceFound = () => true;
+		assert.isTrue(
+			isDeviceDiscoveryDone(false, 100, options({ isRequestedDeviceFound })),
+		);
+	});
+
+	it("keeps waiting for the requested device when another one shows up", () => {
+		const isRequestedDeviceFound = () => false;
+		assert.isFalse(
+			isDeviceDiscoveryDone(true, 5000, options({ isRequestedDeviceFound })),
+		);
+	});
+
+	it("gives other devices time to arrive when none was requested", () => {
+		assert.isFalse(isDeviceDiscoveryDone(true, 100, options()));
+		assert.isTrue(isDeviceDiscoveryDone(true, 2000, options()));
+	});
+
+	it("keeps waiting while no device was found", () => {
+		assert.isFalse(isDeviceDiscoveryDone(false, 5000, options()));
+	});
+
+	it("doesn't end early on a full discovery", () => {
+		assert.isFalse(
+			isDeviceDiscoveryDone(true, 5000, options({ fullDiscovery: true })),
+		);
+	});
+
+	it("works without options", () => {
+		assert.isTrue(isDeviceDiscoveryDone(true, 2000));
+	});
+});