fix(replay): Route network detail through sentry-java's own hint by hkarmoush · Pull Request #3980 · getsentry/sentry-dart

hkarmoush · 2026-08-24T12:47:26Z

📜 Description

Reworks the Session Replay network-detail leak fix per @buenaflor's review on #3900.

Dart side keeps captured HTTP request/response detail off the shared http breadcrumb, passing it via a Hint instead (unchanged from the earlier attempt).
Android side no longer uses a bespoke JNI side channel (ReplayNetworkDetailCache, keyed by a generated replay_request_id) to get that detail into a replay recording. Instead it's delivered through sentry-java's own SENTRY_REPLAY_NETWORK_DETAILS hint - the same mechanism SentryOkHttpInterceptor already uses - so DefaultReplayBreadcrumbConverter's own (already-tested) conversion logic builds the replay event, rather than a hand-rolled reimplementation.
addBreadcrumb now carries the network detail directly instead of a separate captureReplayNetworkDetail call, so there's one atomic native call instead of two - removing the race Bugbot flagged on the previous side-channel approach (fix(replay): Stop network detail capture leaking into non-replay events #3947).

💡 Motivation and Context

Closes the leak in #3900: captured HTTP bodies/headers (opt-in via enableReplayNetworkDetailsCapturing) were riding along on the shared http breadcrumb and ending up on unrelated events and native crash events, not just replay recordings.

Supersedes #3947, which used a bespoke JNI cache that Bugbot flagged a race in and @buenaflor asked to be reworked to route through sentry-java's existing mechanism instead: #3900 (comment)

💚 How did you test it?

Unit tests updated at the NativeScopeObserver / SentryNativeJava.addBreadcrumb seams (single-call contract, request/response detail merging).
dart analyze clean on both sentry and sentry_flutter; full test suites pass.
The new Android JNI binding entry (addBreadcrumbFromJsonBytes overload) is hand-authored, mirroring the existing pattern for [B descriptors in binding.dart, since regenerating it needs a full Android build toolchain not available in this environment - flagging for verification against a real jnigen run before merge.

📝 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
Public API changes reviewed by another Mobile SDK team member or implemented according to the develop docs spec
No breaking changes

🔮 Next steps

Would like a maintainer (or CI with a real Android toolchain) to verify the hand-authored JNI binding entry in binding.dart against an actual jnigen run before merging.

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buenaflor · 2026-09-01T15:38:36Z

+        if (scopeObserver is HintAwareScopeObserver) {
+          await (scopeObserver as HintAwareScopeObserver)
+              .addBreadcrumbWithHint(addedBreadcrumb, resolvedHint);
+        } else {
+          await scopeObserver.addBreadcrumb(addedBreadcrumb);
+        }


Suggested change

if (scopeObserver is HintAwareScopeObserver) {

await (scopeObserver as HintAwareScopeObserver)

.addBreadcrumbWithHint(addedBreadcrumb, resolvedHint);

} else {

await scopeObserver.addBreadcrumb(addedBreadcrumb);

}

if (scopeObserver case final HintAwareScopeObserver observer) {

await observer.addBreadcrumbWithHint(addedBreadcrumb, resolvedHint);

} else {

await scopeObserver.addBreadcrumb(addedBreadcrumb);

}

making it a bit more nicer with newer Dart features

buenaflor · 2026-09-01T15:40:56Z

+  // Hand-authored overload, mirroring addBreadcrumbFromJsonBytes above but
+  // for the two-byte-array descriptor shape (`([B[B)V`), since regenerating
+  // this file requires `scripts/generate-jni-bindings.sh`, which needs a
+  // full Android build toolchain not available in this environment. Re-run
+  // that script (or otherwise verify against a real jnigen run) before
+  // merging.
+  static final _id_addBreadcrumbFromJsonBytes$1 = _class.staticMethodId(
+    r'addBreadcrumbFromJsonBytes',
+    r'([B[B)V',
+  );
+
+  static final _addBreadcrumbFromJsonBytes$1 =


let's not hand-roll this. please re-generate this with e.g Flutter 3.44

Use a pattern match instead of an `is` test followed by a redundant `as` cast when dispatching breadcrumbs to HintAwareScopeObserver. Review feedback from getsentry#3980.

Session Replay's opt-in HTTP body/header capture attached its data to the shared http breadcrumb, which then rode along into every subsequent Dart-captured error/transaction event and, on Android, into native crash events too - not just replay recordings (getsentry#3900). Request/response detail is now delivered via a Hint instead of breadcrumb.data, so it's never stored on the Scope. On Android it reaches the replay breadcrumb converter through a new side channel (ReplayNetworkDetailCache, correlated by an opaque replay_request_id) that never touches native Scope, closing the crash-event leak without touching the shipped Android replay rendering. iOS/FFI/Web never see the detail at all now, closing a zero-benefit leak there too (iOS doesn't render it in replay). Note: the Kotlin/Android native changes, including a hand-authored addition to the auto-generated JNI bindings in lib/src/native/java/binding.dart, could not be compiled or tested in this environment (no Android SDK/JDK/cmake available). They mirror existing generated/native patterns exactly but need verification via scripts/generate-jni-bindings.sh and a real device/emulator run before this is considered ready to ship.

…er API Populate ReplayNetworkDetailCache before the breadcrumb lands on the native Scope, closing the window where a replay segment built in between would never see the request/response detail. ScopeObserver.addBreadcrumb keeps its original one-argument signature so existing implementors aren't broken; a new opt-in HintAwareScopeObserver interface carries the Hint for observers (like NativeScopeObserver) that need it.

Per buenaflor's review on getsentry#3900: stop using a bespoke JNI side channel (ReplayNetworkDetailCache) to get captured HTTP request/response detail from Dart into a replay recording, since sentry-java's DefaultReplayBreadcrumbConverter already supports this via a SENTRY_REPLAY_NETWORK_DETAILS Hint (the same mechanism sentry-android's OkHttp integration uses). addBreadcrumb now carries the network detail directly instead of a separate captureReplayNetworkDetail call, so there's one atomic native call instead of two - removing the race Bugbot flagged on the earlier side-channel approach.

Use a pattern match instead of an `is` test followed by a redundant `as` cast when dispatching breadcrumbs to HintAwareScopeObserver. Review feedback from getsentry#3980.

hkarmoush requested review from buenaflor and denrase as code owners August 24, 2026 12:47

cursor Bot reviewed Aug 24, 2026

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Comment thread packages/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutterPlugin.kt

hkarmoush force-pushed the fix-replay-network-detail-leak-local branch from 03b6649 to 0321cf3 Compare August 31, 2026 08:00

cursor Bot reviewed Aug 31, 2026

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Comment thread packages/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutterPlugin.kt

buenaflor reviewed Sep 1, 2026

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hkarmoush force-pushed the fix-replay-network-detail-leak-local branch from 0321cf3 to 8d16feb Compare September 7, 2026 11:10

sentry Bot reviewed Sep 7, 2026

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Comment thread packages/flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutterPlugin.kt

hkarmoush added 4 commits September 18, 2026 00:10

refactor(dart): Simplify hint-aware observer check

e8e3046

Use a pattern match instead of an `is` test followed by a redundant `as` cast when dispatching breadcrumbs to HintAwareScopeObserver. Review feedback from getsentry#3980.

hkarmoush force-pushed the fix-replay-network-detail-leak-local branch from 8d16feb to e8e3046 Compare September 17, 2026 22:11

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fix(replay): Route network detail through sentry-java's own hint - #3980

fix(replay): Route network detail through sentry-java's own hint#3980
hkarmoush wants to merge 4 commits into
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hkarmoush:fix-replay-network-detail-leak-local

hkarmoush commented Aug 24, 2026 •

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hkarmoush commented Aug 24, 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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hkarmoush commented Aug 24, 2026 •

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