fix(flutter): Release Android JNI refs by buenaflor · Pull Request #3712 · getsentry/sentry-dart

buenaflor · 2026-05-19T14:13:45Z

📜 Description

Release Android JNI refs in the Flutter replay and load debug image paths

This releases the replay Hint callback object after processing replay privacy options, releases the intermediate replay recording through the existing arena, and dedupes debug-image instruction addresses before creating JString refs.

💡 Motivation and Context

These paths can otherwise retain JNI global refs longer than needed while Android replay and debug-image loading are active.

Closes #3696

💚 How did you test it?

fvm dart format lib/src/native/java/sentry_native_java.dart lib/src/native/java/sentry_native_java_init.dart

fvm flutter analyze lib/src/native/java/sentry_native_java.dart lib/src/native/java/sentry_native_java_init.dart

fvm flutter test test/native/sentry_native_java_test.dart

Tried fvm flutter test -d emulator-5554 example/integration_test/native_jni_utils_test.dart, but it fails to compile in the current device-test context because package:test is unavailable for that target.

📝 Checklist

I reviewed submitted code
I added tests to verify changes
No new PII added or SDK only sends newly added PII if sendDefaultPii is enabled
I updated the docs if needed
All tests passing
No breaking changes

🔮 Next steps

Confirm the Android JNI integration test setup separately if reviewers want device-level coverage for these helpers.

Made with Cursor

Send large Android scope payloads as JSON bytes instead of recursively constructing Java maps and lists through JNI. This keeps nested user data structured while reducing per-entry JNI object churn. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Clarify that large or arbitrary Dart collection payloads should cross JNI as JSON bytes, while primitives and small controlled payloads can use direct conversion. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Keep the Android JSON reader helper within ktlint formatting limits after adding the scope sync byte-array bridge. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Wrap all native JSON conversion when branches consistently so ktlint accepts the multiline Kotlin helper added for Android scope sync. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Use the existing native boundary normalizer before encoding Android scope payloads as JSON bytes instead of maintaining a second normalization helper. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Keep null values when converting JSON object and array payloads on Android so the bridge remains lossless before native model deserialization. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Cache JSON deserializers for scope sync payloads and replace the broad Any extension with a private helper function for Kotlin JSON conversion. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Use the Java SDK JSON reader for context payload parsing instead of a custom recursive org.json conversion helper. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Document that the Android JSON reader accepts root-level primitives so future changes do not replace it with object-only parsing. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Route Android context values through sentry-java's typed overloads so primitive Dart context values are serialized as valid context objects. Regenerate JNI bindings after removing the unused object overload entrypoint. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Release replay callback JNI handles after processing replay privacy options, and avoid creating duplicate JNI strings when loading debug images. This reduces leaked global refs in Android replay and debug image paths. Fixes #3696 Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

github-actions · 2026-05-19T14:22:59Z

Semver Impact of This PR

🟢 Patch (bug fixes)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

Fixes

Dart

Make sentryOnError synchronous in runZonedGuarded by theprantadutta in #3697
Route SDK diagnostic logs to browser console on web by theprantadutta in #3698

Flutter

Release Android JNI refs by buenaflor in #3712

Release replay JNI refs by buenaflor in #3699

Enhancements

(flutter) Optimize Android scope sync by buenaflor in #3708

Internal Changes

(flutter) Align CI with stable SwiftPM defaults by buenaflor in #3710

_{🤖 This preview updates automatically when you update the PR.}

codecov · 2026-05-19T14:25:17Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.91%. Comparing base (79df88f) to head (696867d).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3712      +/-   ##
==========================================
+ Coverage   85.07%   91.91%   +6.83%     
==========================================
  Files         238      105     -133     
  Lines        8485     3737    -4748     
==========================================
- Hits         7219     3435    -3784     
+ Misses       1266      302     -964

Flag	Coverage Δ
sentry	`?`
sentry_dio	`?`
sentry_drift	`?`
sentry_file	`?`
sentry_firebase_remote_config	`100.00% <ø> (ø)`
sentry_flutter	`91.53% <ø> (?)`
sentry_hive	`?`
sentry_isar	`?`
sentry_link	`?`
sentry_logging	`?`
sentry_sqflite	`?`
sentry_supabase	`97.27% <ø> (ø)`

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

Update the native context sync test to match the Android bridge's valid serialized shape for primitive context values. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Use a single arena for replay callback JNI temporaries and avoid releasing map keys before removing privacy options from the payload. Refs #3696 Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Copilot

Pull request overview

This PR tightens JNI reference cleanup in the Android-specific Flutter paths to prevent global ref retention while replay and debug-image loading are active. It deduplicates instruction addresses before allocating JString refs, switches the rrweb privacy-option mutation to explicit arena-managed handles (replacing removeWhere with a manual iterator so each materialized key/value can be released), and releases the replay callback's hint reference once the callback finishes.

Changes:

In loadDebugImages, dedupe instruction-address strings before converting them to JString, so duplicate addresses don't produce duplicate JNI refs that all need to be released.
In createBeforeSendReplayCallback, route every intermediate JNI object (replayRecording, payload data, optionsEvent, options payload map, key iterator and current keys, removed values, and jMap) through the existing arena.
Wrap the callback body in try/finally so hint.release() is always invoked after processing.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
packages/flutter/lib/src/native/java/sentry_native_java.dart	Deduplicate instruction addresses before allocating `JString` refs in `loadDebugImages`.
packages/flutter/lib/src/native/java/sentry_native_java_init.dart	Arena-release intermediate replay JNI handles and release the `hint` ref in a `finally` block in the `BeforeSendReplay` callback.

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…r-android-jni-leaks

github-actions · 2026-05-19T22:47:05Z

Android Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	368.82 ms	355.98 ms	-12.84 ms
Size	14.55 MiB	15.87 MiB	1.31 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`fec56a1`	370.66 ms	369.28 ms	-1.38 ms
`ea06d23`	371.10 ms	358.56 ms	-12.54 ms
`dbd526b`	504.88 ms	569.02 ms	64.15 ms
`2cf9161`	454.12 ms	512.67 ms	58.55 ms
`640ad0c`	466.00 ms	552.67 ms	86.67 ms
`79f6b41`	469.66 ms	525.90 ms	56.24 ms
`40751bf`	421.09 ms	424.82 ms	3.73 ms
`13b8895`	372.91 ms	370.13 ms	-2.79 ms
`cba2765`	405.98 ms	422.02 ms	16.04 ms
`a920b0f`	391.75 ms	378.98 ms	-12.77 ms

App size

Revision	Plain	With Sentry	Diff
`fec56a1`	14.31 MiB	15.49 MiB	1.19 MiB
`ea06d23`	13.93 MiB	15.18 MiB	1.25 MiB
`dbd526b`	6.54 MiB	7.69 MiB	1.15 MiB
`2cf9161`	6.54 MiB	7.70 MiB	1.16 MiB
`640ad0c`	6.54 MiB	7.69 MiB	1.15 MiB
`79f6b41`	6.54 MiB	7.69 MiB	1.15 MiB
`40751bf`	14.31 MiB	15.49 MiB	1.19 MiB
`13b8895`	13.93 MiB	15.18 MiB	1.25 MiB
`cba2765`	13.93 MiB	15.18 MiB	1.25 MiB
`a920b0f`	14.09 MiB	15.28 MiB	1.19 MiB

Previous results on branch: buenaflor/fix/flutter-android-jni-leaks

Startup times

Revision	Plain	With Sentry	Diff
`f4d8991`	351.66 ms	342.51 ms	-9.15 ms
`68412d3`	430.18 ms	442.46 ms	12.27 ms

App size

Revision	Plain	With Sentry	Diff
`f4d8991`	14.55 MiB	15.87 MiB	1.31 MiB
`68412d3`	14.55 MiB	15.87 MiB	1.31 MiB

github-actions · 2026-05-19T22:51:20Z

iOS Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1252.49 ms	1257.56 ms	5.07 ms
Size	5.83 MiB	6.28 MiB	461.20 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`79df88f`	1255.16 ms	1263.51 ms	8.35 ms
`765aa8b`	1259.09 ms	1269.90 ms	10.82 ms
`7cfee3b`	1260.90 ms	1273.14 ms	12.24 ms
`dc53d48`	1252.06 ms	1255.61 ms	3.55 ms
`027fcfd`	1239.04 ms	1243.65 ms	4.61 ms
`584a4b7`	1235.62 ms	1233.62 ms	-2.00 ms
`396cb30`	1265.06 ms	1265.73 ms	0.67 ms
`e1ab497`	1260.92 ms	1260.22 ms	-0.69 ms
`a920b0f`	1254.67 ms	1261.62 ms	6.95 ms
`640ad0c`	1241.04 ms	1253.96 ms	12.92 ms

App size

Revision	Plain	With Sentry	Diff
`79df88f`	5.83 MiB	6.28 MiB	461.20 KiB
`765aa8b`	7.86 MiB	9.44 MiB	1.58 MiB
`7cfee3b`	20.70 MiB	22.46 MiB	1.75 MiB
`dc53d48`	5.65 MiB	6.09 MiB	446.96 KiB
`027fcfd`	5.73 MiB	6.17 MiB	455.48 KiB
`584a4b7`	5.66 MiB	6.10 MiB	451.31 KiB
`396cb30`	5.53 MiB	6.01 MiB	488.17 KiB
`e1ab497`	5.53 MiB	6.01 MiB	487.96 KiB
`a920b0f`	5.66 MiB	6.10 MiB	453.28 KiB
`640ad0c`	7.86 MiB	9.44 MiB	1.58 MiB

Previous results on branch: buenaflor/fix/flutter-android-jni-leaks

Startup times

Revision	Plain	With Sentry	Diff
`68412d3`	1235.45 ms	1240.79 ms	5.34 ms
`f4d8991`	1246.58 ms	1257.05 ms	10.47 ms

App size

Revision	Plain	With Sentry	Diff
`68412d3`	5.83 MiB	6.28 MiB	461.19 KiB
`f4d8991`	5.83 MiB	6.28 MiB	461.20 KiB

buenaflor · 2026-05-21T08:41:17Z

+      final instructionAddresses =
+          stackTrace.frames.map((f) => f.instructionAddr).nonNulls.toSet();
+
+      instructionAddressJStrings =
+          instructionAddresses.map((s) => s.toJString()).toSet();


dedupe before transforming to java string (micro optimization)

buenaflor · 2026-05-21T08:41:44Z

+            final data = replayRecording?.getPayload()?.use(
+                  (payload) => payload.firstOrNull,
+                )?..releasedBy(arena);
+            if (data?.isA(native.RRWebOptionsEvent.type) ?? false) {
+              final optionsEvent = data!.as(native.RRWebOptionsEvent.type)
+                ..releasedBy(arena);
+              final payload = optionsEvent.getOptionsPayload()
+                ..releasedBy(arena);

-            final jMap = dartToJMap(options.privacy.toJson());
-            payload?.addAll(jMap);
-            jMap.release();
-          }
-        });
-        return sentryReplayEvent;
+              final keys = payload.keys..releasedBy(arena);
+              final iterator = keys.iterator..releasedBy(arena);
+              final keysToRemove = <JString>[];
+              while (iterator.moveNext()) {
+                final key = iterator.current?..releasedBy(arena);
+                if (key?.toDartString().contains('mask') ?? false) {
+                  keysToRemove.add(key!);
+                }
+              }
+
+              for (final key in keysToRemove) {
+                payload.remove(key)?.releasedBy(arena);
+              }
+
+              final jMap = dartToJMap(options.privacy.toJson())
+                ..releasedBy(arena);
+              payload.addAll(jMap);
+            }
+          });
+          return sentryReplayEvent;
+        } finally {
+          hint.release();


release hint and consolidate to releasing via the arena

buenaflor and others added 12 commits May 19, 2026 11:05

style(flutter): Wrap JNI JSON reader helper

b85800e

Keep the Android JSON reader helper within ktlint formatting limits after adding the scope sync byte-array bridge. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

style(flutter): Apply ktlint when-branch formatting

e15b49d

Wrap all native JSON conversion when branches consistently so ktlint accepts the multiline Kotlin helper added for Android scope sync. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

ref(flutter): Reuse native data normalizer

7d8ec5f

Use the existing native boundary normalizer before encoding Android scope payloads as JSON bytes instead of maintaining a second normalization helper. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

fix(flutter): Preserve nulls in Android JSON bridge

b43bb60

Keep null values when converting JSON object and array payloads on Android so the bridge remains lossless before native model deserialization. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

perf(flutter): Reuse Android JSON deserializers

a713631

Cache JSON deserializers for scope sync payloads and replace the broad Any extension with a private helper function for Kotlin JSON conversion. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

ref(flutter): Use SDK JSON object reader

c666afd

Use the Java SDK JSON reader for context payload parsing instead of a custom recursive org.json conversion helper. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

Merge branch 'main' into perf/android-scope-sync-json

ab3bce0

docs(flutter): Clarify JSON reader parsing

f9a84b1

Document that the Android JSON reader accepts root-level primitives so future changes do not replace it with object-only parsing. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

buenaflor and others added 2 commits May 19, 2026 16:35

test(flutter): Expect wrapped Android contexts

e2bd84b

Update the native context sync test to match the Android bridge's valid serialized shape for primitive context values. Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

fix(flutter): Release replay JNI refs safely

68412d3

Use a single arena for replay callback JNI temporaries and avoid releasing map keys before removing privacy options from the payload. Refs #3696 Co-Authored-By: GPT-5.5 <[email protected]> Co-authored-by: Cursor <[email protected]>

buenaflor marked this pull request as ready for review May 19, 2026 16:26

buenaflor requested a review from denrase as a code owner May 19, 2026 16:26

Copilot AI review requested due to automatic review settings May 19, 2026 16:26

Copilot started reviewing on behalf of buenaflor May 19, 2026 16:27 View session

Copilot AI reviewed May 19, 2026

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Merge branch 'perf/android-scope-sync-json' into buenaflor/fix/flutte…

f5c65b6

…r-android-jni-leaks

Base automatically changed from perf/android-scope-sync-json to main May 19, 2026 22:25

Merge branch 'main' into buenaflor/fix/flutter-android-jni-leaks

696867d

buenaflor commented May 21, 2026

View reviewed changes

denrase approved these changes May 21, 2026

View reviewed changes

buenaflor merged commit 3fe9e80 into main May 21, 2026
92 of 93 checks passed

buenaflor deleted the buenaflor/fix/flutter-android-jni-leaks branch May 21, 2026 13:46

github-actions Bot mentioned this pull request May 29, 2026

Investigate JNI for possible memory leaks and misuse #3696

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buenaflor commented May 19, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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📜 Description

💡 Motivation and Context

💚 How did you test it?

📝 Checklist

🔮 Next steps

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Semver Impact of This PR

Fixes

Dart

Flutter

Enhancements

Internal Changes

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github-actions Bot commented May 19, 2026

Android Performance metrics 🚀

Baseline results on branch: main

Startup times

App size

Previous results on branch: buenaflor/fix/flutter-android-jni-leaks

Startup times

App size

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github-actions Bot commented May 19, 2026

iOS Performance metrics 🚀

Baseline results on branch: main

Startup times

App size

Previous results on branch: buenaflor/fix/flutter-android-jni-leaks

Startup times

App size

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buenaflor May 21, 2026

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buenaflor commented May 19, 2026 •

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