Android Leak Memory on Purchases.getOfferings()

[meomap]

• I have updated Purchases SDK to the latest version
• I have read the Contribution Guidelines
• I have searched the Community
• I have read docs.revenuecat.com
• I have searched for existing Github issues

Environment

• Output of flutter doctor

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.7.12, on macOS 12.6.3 21G419 darwin-x64)
[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.2)
[✓] Xcode - develop for iOS and macOS (Xcode 14.2)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2022.2)
[✓] VS Code (version 1.78.1)
[✓] Connected device (2 available)
[✓] HTTP Host Availability

• Version of purchases-flutter
  4.12.0

• Testing device version e.g.: Android API 28

• How often the issue occurs - Problem is reproducible in dev

• [Debug logs]

┬───
│ GC Root: Input or output parameters in native code
│
├─ android.os.MessageQueue instance
│    Leaking: NO (MessageQueue#mQuitting is false)
│    HandlerThread: "main"
│    ↓ MessageQueue[1]
│                  ~~~
├─ android.os.Message instance
│    Leaking: UNKNOWN
│    Retaining 547 B in 21 objects
│    Message.what = 0
│    Message.when = 26437502 (267 ms after heap dump)
│    Message.obj = null
│    Message.callback = instance @325425960 of com.android.billingclient.api.zzz
│    Message.target = instance @325426040 of android.os.Handler
│    ↓ Message.callback
│              ~~~~~~~~
├─ com.android.billingclient.api.zzz instance
│    Leaking: UNKNOWN
│    Retaining 462 B in 19 objects
│    ↓ zzz.zzb
│          ~~~
├─ com.android.billingclient.api.zzy instance
│    Leaking: UNKNOWN
│    Retaining 418 B in 17 objects
│    ↓ zzy.zza
│          ~~~
├─ com.revenuecat.purchases.google.BillingWrapper$$ExternalSyntheticLambda5
│  instance
│    Leaking: UNKNOWN
│    Retaining 406 B in 16 objects
│    ↓ BillingWrapper$$ExternalSyntheticLambda5.f$3
│                                               ~~~
├─ com.revenuecat.purchases.google.
│  BillingWrapper$querySkuDetailsAsync$1$1$$ExternalSyntheticLambda0 instance
│    Leaking: UNKNOWN
│    Retaining 297 B in 10 objects
│    ↓ BillingWrapper$querySkuDetailsAsync$1$1$$ExternalSyntheticLambda0.f$1
│                                                                        ~~~
├─ com.revenuecat.purchases.Purchases$getSkuDetails$1 instance
│    Leaking: UNKNOWN
│    Retaining 28 B in 1 objects
│    Anonymous subclass of kotlin.jvm.internal.Lambda
│    ↓ Purchases$getSkuDetails$1.$onCompleted
│                                ~~~~~~~~~~~~
├─ com.revenuecat.purchases.Purchases$fetchAndCacheOfferings$1$1 instance
│    Leaking: UNKNOWN
│    Retaining 24 B in 1 objects
│    Anonymous subclass of kotlin.jvm.internal.Lambda
│    ↓ Purchases$fetchAndCacheOfferings$1$1.$completion
│                                           ~~~~~~~~~~~
├─ com.revenuecat.purchases.ListenerConversionsKt$receiveOfferingsCallback$1
│  instance
│    Leaking: UNKNOWN
│    Retaining 56.4 kB in 1095 objects
│    Anonymous class implementing com.revenuecat.purchases.interfaces.
│    ReceiveOfferingsCallback
│    ↓ ListenerConversionsKt$receiveOfferingsCallback$1.$onError
│                                                       ~~~~~~~~
├─ com.revenuecat.purchases.hybridcommon.CommonKt$getOfferings$1 instance
│    Leaking: UNKNOWN
│    Retaining 16 B in 1 objects
│    Anonymous subclass of kotlin.jvm.internal.Lambda
│    ↓ CommonKt$getOfferings$1.$onResult
│                              ~~~~~~~~~
├─ com.revenuecat.purchases_flutter.PurchasesFlutterPlugin$4 instance
│    Leaking: UNKNOWN
│    Retaining 56.4 kB in 1092 objects
│    Anonymous class implementing com.revenuecat.purchases.hybridcommon.OnResult
│    ↓ PurchasesFlutterPlugin$4.val$result
│                               ~~~~~~~~~~
├─ io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler$1 instance
│    Leaking: UNKNOWN
│    Retaining 56.4 kB in 1091 objects
│    Anonymous class implementing io.flutter.plugin.common.MethodChannel$Result
│    ↓ MethodChannel$IncomingMethodCallHandler$1.val$reply
│                                                ~~~~~~~~~
├─ io.flutter.embedding.engine.dart.DartMessenger$Reply instance
│    Leaking: UNKNOWN
│    Retaining 32 B in 2 objects
│    ↓ DartMessenger$Reply.flutterJNI
│                          ~~~~~~~~~~
├─ io.flutter.embedding.engine.FlutterJNI instance
│    Leaking: UNKNOWN
│    Retaining 232 B in 15 objects
│    ↓ FlutterJNI.localizationPlugin
│                 ~~~~~~~~~~~~~~~~~~
├─ io.flutter.plugin.localization.LocalizationPlugin instance
│    Leaking: UNKNOWN
│    Retaining 32 B in 2 objects
│    context instance of com.my.app.MainActivity with mDestroyed
│    = true
│    ↓ LocalizationPlugin.context
│                         ~~~~~~~
╰→ com.my.app.MainActivity instance
​     Leaking: YES (ObjectWatcher was watching this because com.my.
​     app.MainActivity received Activity#onDestroy() callback and
​     Activity#mDestroyed is true)
​     Retaining 47.0 kB in 710 objects
​     key = 83b0362b-bc37-4734-aa21-79b3af57c8e4
​     watchDurationMillis = 5604
​     retainedDurationMillis = 582
​     mApplication instance of android.app.Application
​     mBase instance of android.app.ContextImpl

• Steps to reproduce:

1. Install leakcanary debugImplementation 'com.squareup.leakcanary:leakcanary-android:2.10'
2. Fetch offering Offerings offerings = await Purchases.getOfferings()
3. Open then close the app

Other information

Problem seems gone when I replaced getOnResult(result) with a dedicated Result var for getOffering that can be set null when engine detached

Describe the bug

Plugin leaked main activity context

[RCGitBot]

👀 SDKONCALL-276 We've just linked this issue to our internal tracker and notified the team. Thank you for reporting, we're checking this out!

[vegaro]

Thanks for reporting this issue. Can you please share a snippet with the changes you did to make the leak disappear? We are using Result in the same way in all our method calls so it's kinda weird this only happens for getOfferings. Are you accessing the activity in any way from your Flutter code?

[meomap]

@vegaro Sure here is my workaround

diff --git a/android/src/main/java/com/revenuecat/purchases_flutter/PurchasesFlutterPlugin.java b/android/src/main/java/com/revenuecat/purchases_flutter/PurchasesFlutterPlugin.java
index 42fe666..edaa1ca 100644
--- a/android/src/main/java/com/revenuecat/purchases_flutter/PurchasesFlutterPlugin.java
+++ b/android/src/main/java/com/revenuecat/purchases_flutter/PurchasesFlutterPlugin.java
@@ -52,6 +52,7 @@ public class PurchasesFlutterPlugin implements FlutterPlugin, MethodCallHandler,
     @Nullable private Context applicationContext;
     @Nullable private MethodChannel channel;
     @Nullable private Activity activity;
+    @Nullable private Result offeringResult;
 
     private final Handler handler = new Handler(Looper.getMainLooper());
 
@@ -97,6 +98,7 @@ public class PurchasesFlutterPlugin implements FlutterPlugin, MethodCallHandler,
         }
         this.channel = null;
         this.applicationContext = null;
+        this.offeringResult = null;
     }
 
     @Override
@@ -389,7 +391,28 @@ public class PurchasesFlutterPlugin implements FlutterPlugin, MethodCallHandler,
     }
 
     private void getOfferings(final Result result) {
-        CommonKt.getOfferings(getOnResult(result));
+        offeringResult = result;
+        CommonKt.getOfferings(new OnResult() {
+            @Override
+            public void onReceived(Map<String, ?> map) {
+                synchronized(this) {
+                    if (offeringResult != null) {
+                        offeringResult.success(map);
+                    }
+                    offeringResult = null;
+                }
+            }
+
+            @Override
+            public void onError(ErrorContainer errorContainer) {
+                synchronized(this) {
+                    if (offeringResult != null) {
+                        reject(errorContainer, offeringResult);
+                    }
+                    offeringResult = null;
+                }
+            }
+        });
     }
 
     private void getProductInfo(ArrayList<String> productIDs, String type, final Result result) {

I use bunch of other plugins so I think they will also access the activity. I don't know but maybe the problem is at stream listener. It's weird that I don't see leak report anymore after applying this change.