From f5066b25a604518784f0e2c89de233afaa6d7fb5 Mon Sep 17 00:00:00 2001
From: Brian Giori <brian.giori@amplitude.com>
Date: Thu, 4 Apr 2024 08:02:10 -0700
Subject: [PATCH] feat: add method to get device ID synchronously (#490)

---
 Sources/Amplitude/Amplitude.m | 15 ++++++++++-----
 Tests/AmplitudeTests.m        |  8 ++++++++
 Tests/SetupTests.m            |  3 ---
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/Sources/Amplitude/Amplitude.m b/Sources/Amplitude/Amplitude.m
index c080ecf6..2c9f3d11 100644
--- a/Sources/Amplitude/Amplitude.m
+++ b/Sources/Amplitude/Amplitude.m
@@ -1669,6 +1669,9 @@ - (NSString *)getAdSupportID {
 }
 
 - (NSString *)getDeviceId {
+    if (self.deviceId == nil) {
+        return [self initializeDeviceId];
+    }
     return self.deviceId;
 }
 
@@ -1677,11 +1680,13 @@ - (long long)getSessionId {
 }
 
 - (NSString *)initializeDeviceId {
-    if (self.deviceId == nil) {
-        self.deviceId = [self.dbHelper getValue:DEVICE_ID];
-        if (![self isValidDeviceId:self.deviceId]) {
-            self.deviceId = [self _getDeviceId];
-            [self.dbHelper insertOrReplaceKeyValue:DEVICE_ID value:self.deviceId];
+    @synchronized (self) {
+        if (self.deviceId == nil) {
+            self.deviceId = [self.dbHelper getValue:DEVICE_ID];
+            if (![self isValidDeviceId:self.deviceId]) {
+                self.deviceId = [self _getDeviceId];
+                [self.dbHelper insertOrReplaceKeyValue:DEVICE_ID value:self.deviceId];
+            }
         }
     }
     return self.deviceId;
diff --git a/Tests/AmplitudeTests.m b/Tests/AmplitudeTests.m
index af997e1f..48ae32ed 100644
--- a/Tests/AmplitudeTests.m
+++ b/Tests/AmplitudeTests.m
@@ -1705,4 +1705,12 @@ - (void)testOpenURLFiresDeepLinkEvent {
     XCTAssertEqualObjects([[event objectForKey:@"event_properties"] objectForKey:kAMPEventPropLinkUrl], @"https://test-app.com");
 }
 
+- (void)testGetDeviceIdAfterInit {
+    NSString *instanceName = @"testGetDeviceIdAfterInit";
+    Amplitude *client = [Amplitude instanceWithName:instanceName];
+    [client initializeApiKey:@"testGetDeviceIdAfterInit"];
+    NSString *deviceId = [client getDeviceId];
+    XCTAssertNotEqualObjects(deviceId, @"");
+}
+
 @end
diff --git a/Tests/SetupTests.m b/Tests/SetupTests.m
index 3d9fdcf4..d1a85467 100644
--- a/Tests/SetupTests.m
+++ b/Tests/SetupTests.m
@@ -115,15 +115,12 @@ - (void)testUserPropertiesSet {
 
 - (void)testSetDeviceId {
     AMPDatabaseHelper *dbHelper = [AMPDatabaseHelper getDatabaseHelper];
-    NSString *initialDeviceId = [self.amplitude getDeviceId];
-    XCTAssertNil(initialDeviceId);  // device id not initialized yet
 
     [self.amplitude initializeApiKey:apiKey];
     [self.amplitude flushQueueWithQueue:self.amplitude.initializerQueue];
     [self.amplitude flushQueue];
     NSString *generatedDeviceId = [self.amplitude getDeviceId];
     XCTAssertNotNil(generatedDeviceId);
-    XCTAssertNotEqualObjects(initialDeviceId, generatedDeviceId);
 #if !TARGET_OS_OSX
     XCTAssertEqual(generatedDeviceId.length, 36);
 #else