[firebase_messaging] StrictMode LeakedClosableViolation in TopicSubscriptionClient / GzipSource

[daniel-pellier-itsap]

Describe the bug

When running the app on Android in Debug mode with StrictMode enabled, a LeakedClosableViolation is thrown during FCM topic synchronization (TopicsSyncTask).

Stack trace

D/StrictMode(24299): StrictMode policy violation: android.os.strictmode.LeakedClosableViolation: A resource was acquired at attached stack trace but never released. See java.io.Closeable for information on avoiding resource leaks.
D/StrictMode(24299): at android.os.StrictMode$AndroidCloseGuardReporter.report(StrictMode.java:1786)
D/StrictMode(24299): at dalvik.system.CloseGuard.warnIfOpen(CloseGuard.java:264)
D/StrictMode(24299): at java.util.zip.Inflater.finalize(Inflater.java:398)
D/StrictMode(24299): at java.lang.Daemons$FinalizerDaemon.doFinalize(Daemons.java:252)
D/StrictMode(24299): at java.lang.Daemons$FinalizerDaemon.runInternal(Daemons.java:239)
D/StrictMode(24299): at java.lang.Daemons$Daemon.run(Daemons.java:105)
D/StrictMode(24299): at java.lang.Thread.run(Thread.java:764)
D/StrictMode(24299): Caused by: java.lang.Throwable: Explicit termination method 'end' not called
D/StrictMode(24299): at dalvik.system.CloseGuard.open(CloseGuard.java:221)
D/StrictMode(24299): at java.util.zip.Inflater.(Inflater.java:114)
D/StrictMode(24299): at com.android.okhttp.okio.GzipSource.(GzipSource.java:62)
D/StrictMode(24299): at com.android.okhttp.internal.http.HttpEngine.unzip(HttpEngine.java:473)
D/StrictMode(24299): at com.android.okhttp.internal.http.HttpEngine.readResponse(HttpEngine.java:648)
D/StrictMode(24299): at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:471)
D/StrictMode(24299): at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:407)
D/StrictMode(24299): at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponseCode(HttpURLConnectionImpl.java:538)
D/StrictMode(24299): at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getResponseCode(DelegatingHttpsURLConnection.java:105)
D/StrictMode(24299): at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:26)
D/StrictMode(24299): at com.google.firebase.messaging.TopicSubscriptionClient.performTopicOperation(TopicSubscriptionClient.java:110)
D/StrictMode(24299): at com.google.firebase.messaging.TopicSubscriptionClient.subscribe(TopicSubscriptionClient.java:60)
D/StrictMode(24299): at com.google.firebase.messaging.TopicsSubscriber.blockingSubscribeToTopic(TopicsSubscriber.java:272)
D/StrictMode(24299): at com.google.firebase.messaging.TopicsSubscriber.performTopicOperation(TopicsSubscriber.java:232)
D/StrictMode(24299): at com.google.firebase.messaging.TopicsSubscriber.syncTopics(TopicsSubscriber.java:188)
D/StrictMode(24299): at com.google.firebase.messaging.TopicsSyncTask.run(TopicsSyncTask.java:101)
D/StrictMode(24299): at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:458)
D/StrictMode(24299): at java.util.concurrent.FutureTask.run(FutureTask.java:266)
D/StrictMode(24299): at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:301)
D/StrictMode(24299): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
D/StrictMode(24299): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
D/StrictMode(24299): at com.google.android.gms.common.util.concurrent.zza.run(com.google.android.gms:play-services-basement@@18.9.0:2)
D/StrictMode(24299): ... 1 more
D/StrictMode(24299): StrictMode policy violation: android.os.strictmode.LeakedClosableViolation: A resource was acquired at attached stack trace but never released. See java.io.Closeable for information on avoiding resource leaks.

[lehcar09]

Hi @daniel-pellier-itsap, thank you for raising this issue. Could you provide the Firebase SDK version you're using? I tried reproducing the error, however, I wasn't able to encounter the problem in BoM version 34.16.0.

Here's the StrictMode policy I used:

		if (BuildConfig.DEBUG) {
			StrictMode.setThreadPolicy(
				StrictMode.ThreadPolicy.Builder()
				.detectAll()
				.penaltyLog()
				.build()
			)
			
			StrictMode.setVmPolicy(
				StrictMode.VmPolicy.Builder()
					.detectAll()
					.penaltyLog()
					.build()
			)
		}

[RyeGordo]

Same underlying transport, different symptom: we're seeing UntaggedSocketViolation (not LeakedClosableViolation) from this exact class/call path, triggered by TopicSubscriptionClient.unsubscribe during a topic unsubscribe (the subscribe path in the original report above presumably hits the same issue).

firebase-messaging BOM 34.17.0

W  android.os.strictmode.UntaggedSocketViolation: Untagged socket detected; use TrafficStats.setTrafficStatsTag() to track all network usage
    at android.os.StrictMode.onUntaggedSocket(StrictMode.java:2581)
    at android.os.StrictMode.noteUntaggedSocket(StrictMode.java:3079)
    at android.net.TrafficStats$SocketTagger.tag(TrafficStats.java:433)
    at libcore.io.BlockGuardOs.tagSocket(BlockGuardOs.java:55)
    at libcore.io.BlockGuardOs.socket(BlockGuardOs.java:419)
    at libcore.io.ForwardingOs.socket(ForwardingOs.java:848)
    at libcore.io.IoBridge.socket(IoBridge.java:840)
    at java.net.PlainSocketImpl.socketCreate(PlainSocketImpl.java:128)
    at java.net.AbstractPlainSocketImpl.create(AbstractPlainSocketImpl.java:128)
    at java.net.Socket.createImpl(Socket.java:514)
    at java.net.Socket.getImpl(Socket.java:577)
    at java.net.Socket.setSoTimeout(Socket.java:1203)
    at com.android.okhttp.internal.io.RealConnection.connectSocket(RealConnection.java:143)
    at com.android.okhttp.internal.io.RealConnection.connect(RealConnection.java:116)
    at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:186)
    at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:128)
    at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:97)
    at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:289)
    at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:232)
    at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:465)
    at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:411)
    at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponseCode(HttpURLConnectionImpl.java:542)
    at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getResponseCode(DelegatingHttpsURLConnection.java:106)
    at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:30)
    at com.google.firebase.messaging.TopicSubscriptionClient.performTopicOperation(TopicSubscriptionClient.java:110)
    at com.google.firebase.messaging.TopicSubscriptionClient.unsubscribe(TopicSubscriptionClient.java:69)
    at com.google.firebase.messaging.TopicsSubscriber.blockingUnsubscribeFromTopic(TopicsSubscriber.java:277)
    at com.google.firebase.messaging.TopicsSubscriber.performTopicOperation(TopicsSubscriber.java:238)
    at com.google.firebase.messaging.TopicsSubscriber.syncTopics(TopicsSubscriber.java:188)
    at com.google.firebase.messaging.TopicsSyncTask.run(TopicsSyncTask.java:101)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:520)
    at java.util.concurrent.FutureTask.run(FutureTask.java:328)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:323)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1100)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at com.google.android.gms.common.util.concurrent.zza.run(com.google.android.gms:play-services-basement@@18.10.0:2)
    at java.lang.Thread.run(Thread.java:1572)

Both violations trace back to the same root cause: TopicSubscriptionClient still goes through the platform's default HttpURLConnection, which on this device resolves to the legacy bundled com.android.okhttp (not the public okhttp3 artifact) -- a transport that doesn't tag its sockets and apparently doesn't reliably close its gzip/inflater resources either. This looks like the same category of issue closed as "won't fix from our side" in #1133 for Remote Config's ConfigFetchHttpClient (same legacy transport, same UntaggedSocketViolation), so flagging here in case a fix for one of these ends up covering the other, since it's the same transport across both Messaging and Remote Config.

[daniel-pellier-itsap]

Hi and thanks for your response, This is an embedded version with Flutter ( https://pub.dev/packages/firebase_core/changelog). We are currently using this one: *4.0.0* Note: This release has breaking changes. BREAKING FEAT: bump iOS SDK to version 12.0.0 (#17549). (b2619e68) BREAKING FEAT: bump Android SDK to version 34.0.0 (#17554). (a5bdc051) I'm going to upgrade our versions to align with the latest releases. We are currently in the dev phase so versions move pretty fast—it's not an issue though, it just shows the project is very active! I'm mostly looking into memory leaks in my app—I've already fixed a few, but I noticed this one was still remaining. We'll probably have to wait for the next SDK release (now 34.15.0). *After upgrading the Flutter versions:* - firebase_core: ^4.12.1 - firebase_analytics: ^12.4.5 - firebase_messaging: ^16.4.3 +--- com.google.firebase:firebase-bom:34.15.0 +--- com.google.firebase:firebase-bom:{strictly 34.15.0} -> 34.15.0 (c) +--- com.google.firebase:firebase-bom:34.15.0 | | +--- com.google.firebase:firebase-bom:34.15.0 (*) | +--- com.google.firebase:firebase-bom:34.15.0 (*) | +--- com.google.firebase:firebase-bom:34.15.0 (*) I/.hyperion.loca(19131): Background concurrent copying GC freed 46920(2MB) AllocSpace objects, 90(2MB) LOS objects, 49% free, 6MB/12MB, paused 193us total 119.156ms D/StrictMode(19131): StrictMode policy violation: android.os.strictmode.LeakedClosableViolation: A resource was acquired at attached stack trace but never released. See java.io.Closeable for information on avoiding resource leaks. D/StrictMode(19131): at android.os.StrictMode$AndroidCloseGuardReporter.report(StrictMode.java:1786) D/StrictMode(19131): at dalvik.system.CloseGuard.warnIfOpen(CloseGuard.java:264) D/StrictMode(19131): at java.util.zip.Inflater.finalize(Inflater.java:398) D/StrictMode(19131): at java.lang.Daemons$FinalizerDaemon.doFinalize(Daemons.java:252) D/StrictMode(19131): at java.lang.Daemons$FinalizerDaemon.runInternal(Daemons.java:239) D/StrictMode(19131): at java.lang.Daemons$Daemon.run(Daemons.java:105) D/StrictMode(19131): at java.lang.Thread.run(Thread.java:764) D/StrictMode(19131): Caused by: java.lang.Throwable: Explicit termination method 'end' not called D/StrictMode(19131): at dalvik.system.CloseGuard.open(CloseGuard.java:221) D/StrictMode(19131): at java.util.zip.Inflater.<init>(Inflater.java:114) D/StrictMode(19131): at com.android.okhttp.okio.GzipSource.<init>(GzipSource.java:62) D/StrictMode(19131): at com.android.okhttp.internal.http.HttpEngine.unzip(HttpEngine.java:473) D/StrictMode(19131): at com.android.okhttp.internal.http.HttpEngine.readResponse(HttpEngine.java:648) D/StrictMode(19131): at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:471) D/StrictMode(19131): at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:407) D/StrictMode(19131): at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponseCode(HttpURLConnectionImpl.java:538) D/StrictMode(19131): at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getResponseCode(DelegatingHttpsURLConnection.java:105) D/StrictMode(19131): at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:26) D/StrictMode(19131): at com.google.firebase.messaging.TopicSubscriptionClient.performTopicOperation(TopicSubscriptionClient.java:110) D/StrictMode(19131): at com.google.firebase.messaging.TopicSubscriptionClient.subscribe(TopicSubscriptionClient.java:60) D/StrictMode(19131): at com.google.firebase.messaging.TopicsSubscriber.blockingSubscribeToTopic(TopicsSubscriber.java:272) D/StrictMode(19131): at com.google.firebase.messaging.TopicsSubscriber.performTopicOperation(TopicsSubscriber.java:232) D/StrictMode(19131): at com.google.firebase.messaging.TopicsSubscriber.syncTopics(TopicsSubscriber.java:188) D/StrictMode(19131): at com.google.firebase.messaging.TopicsSyncTask.run(TopicsSyncTask.java:101) D/StrictMode(19131): at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:458) D/StrictMode(19131): at java.util.concurrent.FutureTask.run(FutureTask.java:266) D/StrictMode(19131): at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:301) D/StrictMode(19131): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) D/StrictMode(19131): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) D/StrictMode(19131): at com.google.android.gms.common.util.concurrent.zza.run(com.google.android.gms:play-services-basement@ @18.9.0:2) D/StrictMode(19131): ... 1 more Have a great day Le ven. 31 juil. 2026 à 19:09, lehcar09 ***@***.***> a écrit :

…

*lehcar09* left a comment (firebase/firebase-android-sdk#8496) <#8496 (comment)> Hi @daniel-pellier-itsap <https://github.com/daniel-pellier-itsap>, thank you for raising this issue. Could you provide the Firebase SDK version you're using? I tried reproducing the error, however, I wasn't able to encounter the problem in BoM version 34.16.0. Here's the StrictMode policy I used: if (BuildConfig.DEBUG) { StrictMode.setThreadPolicy( StrictMode.ThreadPolicy.Builder() .detectAll() .penaltyLog() .build() ) StrictMode.setVmPolicy( StrictMode.VmPolicy.Builder() .detectAll() .penaltyLog() .build() ) } — Reply to this email directly, view it on GitHub <#8496?email_source=notifications&email_token=CKFMXZD77TRRUIVPXYP4F6D5HTHETA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKMJUGU2TGMBTHEY2M4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLDGN5XXIZLSL5RWY2LDNM#issuecomment-5145530391>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/CKFMXZAHDU7DJX74EOXLNH35HTHETAVCNFSNUABFKJSXA33TNF2G64TZHMYTINRZGQYTCOBVHNEXG43VMU5TKMBSGEYTONRYHA32C5QC> . Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS <https://github.com/notifications/mobile/ios/CKFMXZA5WXVFTJYYTRMAGUL5HTHETA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKMJUGU2TGMBTHEY2M4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJKTGN5XXIZLSL5UW64Y> and Android <https://github.com/notifications/mobile/android/CKFMXZG3O4R4CFN76RBYGXD5HTHETA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKMJUGU2TGMBTHEY2M4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLTGN5XXIZLSL5QW4ZDSN5UWI>. Download it today! You are receiving this because you were mentioned.Message ID: ***@***.***>

-- [image: logo-itsap] Daniel PELLIER Développeur(euse) Java Confirmé(e) 85 boulevard Marie et Alexandre Oyon CS 85533 72055 Le Mans Cedex 2

[lehcar09]

Hey @daniel-pellier-itsap, I wasn't able to reproduce the issue in Firebase SDK version 34.15.0 in native Android. I do encounter the issue that was shared by @RyeGordo.

From what I gather, this seems to be native Android issue rather than the SDK, but I'll raise this to our engineers and see what we can do here. Thanks!

--
Update: This has been escalated in b/543352048

[eldhosembabu]

Added a possible fix here: #8534

Hopefully this should resolve the issue.

The fix will be rolled out in next release (25.1.2). Closing this issue for now. Feel free to re-open if the fix is not working with the latest SDK release.