[firebase_crashlytics] OutOfMemoryError inside CrashlyticsReportPersistence.writeTextFile on Firebase background thread

[Milap-GSM]

Is there an existing issue for this?

• I have searched the existing issues.

Which plugins are affected?

Crashlytics, Core

Which platforms are affected?

Android

Description

We are seeing a Fatal OutOfMemoryError triggered inside Firebase Crashlytics’ internal crash-persistence pipeline.
The crash occurs when Crashlytics attempts to persist event files through:

CrashlyticsReportPersistence.writeTextFile() SessionReportingCoordinator.persistEvent()

This is happening in production, across multiple app versions and devices (mainly Samsung, Google).
Crashlytics is failing to allocate even small byte arrays (~128 KB), which suggests:

• A possible memory leak inside Crashlytics’ persistence layer
• Large or repeatedly queued reports
• A threadpool backlog created by Firebase’s CustomThreadFactory
• This is not caused by our app code—we do not write custom large Crashlytics events.
• Occurs in background Firebase worker threads
• Affects users running Android 13+ and even Android 15 (preview)

Reproducing the issue

This issue is not directly reproducible inside development, but visible consistently in production Crashlytics.

General pattern:

• App runs normally.
• Crashlytics captures an event and attempts to persist it.
• Firebase background thread (CustomThreadFactory) tries to write event file.
• Device has low free heap.
• Crashlytics throws:
  java.lang.OutOfMemoryError: Failed to allocate 131584 bytes
  No custom steps on app side reliably trigger this; it appears internal to Crashlytics.

Firebase Core version

3.12.1

Flutter Version

3.27.3

Relevant Log Output

Fatal Exception: java.lang.OutOfMemoryError
Failed to allocate a 131584 byte allocation with 124824 free bytes and 121KB until OOM

at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:145)
at java.io.OutputStreamWriter.write(OutputStreamWriter.java:223)
at java.io.Writer.write(Writer.java:249)
at com.google.firebase.crashlytics.internal.persistence.CrashlyticsReportPersistence.writeTextFile(CrashlyticsReportPersistence.java:415)
at com.google.firebase.crashlytics.internal.persistence.CrashlyticsReportPersistence.persistEvent(CrashlyticsReportPersistence.java:140)
at com.google.firebase.crashlytics.internal.common.SessionReportingCoordinator.lambda$persistEvent$0(SessionReportingCoordinator.java:352)
at com.google.firebase.crashlytics.internal.concurrency.CrashlyticsWorker.lambda$submit$1(CrashlyticsWorker.java:96)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1156)
at com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0(CustomThreadFactory.java:47)
at java.lang.Thread.run(Thread.java:1119)

Flutter dependencies

Expand Flutter dependencies snippet

- firebase_core_platform_interface 5.4.2 [collection flutter flutter_test meta plugin_platform_interface]
- firebase_core_web 2.24.0 [firebase_core_platform_interface flutter flutter_web_plugins meta web]
- firebase_crashlytics_platform_interface 3.8.4 [_flutterfire_internals collection firebase_core flutter meta plugin_platform_interface]

transitive dependencies:
- _flutterfire_internals 1.3.53 [collection firebase_core firebase_core_platform_interface flutter meta]
- firebase_analytics_platform_interface 4.3.4 [_flutterfire_internals firebase_core flutter meta plugin_platform_interface]
- firebase_analytics_web 0.5.10+10 [_flutterfire_internals firebase_analytics_platform_interface firebase_core firebase_core_web flutter flutter_web_plugins]
- firebase_core_platform_interface 5.4.2 [collection flutter flutter_test meta plugin_platform_interface]
- firebase_core_web 2.24.0 [firebase_core_platform_interface flutter flutter_web_plugins meta web]
- firebase_crashlytics_platform_interface 3.8.4 [_flutterfire_internals collection firebase_core flutter meta plugin_platform_interface]
 

Additional context and comments

• Crash appears across multiple app versions, so it’s not tied to a specific release.
• We do not generate unusually large Crashlytics logs.
• This appears strongly related to Crashlytics’ internal event queue / file writing.
• A fix or investigation would help significantly as this is currently a production-level crash.
  If maintainers need additional logs, symbolicated events, I can provide them.

[SelaseKay]

Hi @Milap-GSM, I see you're using an outdated version of firebase_core. Could you update firebase_core and firebase_crashlytics to the latest versions and observe if issue still persists?

[google-oss-bot]

Hey @Milap-GSM. We need more information to resolve this issue but there hasn't been an update in 7 weekdays. I'm marking the issue as stale and if there are no new updates in the next 7 days I will close it automatically.

If you have more information that will help us get to the bottom of this, just add a comment!