Refactor: move native breadcrumbs sync to FFI/JNI

[buenaflor]

📜 Description

Part of FFI/JNI refactorings

💡 Motivation and Context

Partly completes #3204

💚 How did you test it?

Manual tests, integration test

📝 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

[denrase]

Just a small comment regarding internal obj conversion. If we'll use this elsewhere, it would make sense to move to a util and add tests.

[cursor]

Bug: JNI Object Leaks in Dart-to-Java Conversion

JNI objects created during Dart-to-Java conversion in _dartToJList and _dartToJMap are not consistently released. This includes JString keys from entry.key.toJString() in _dartToJMap and JObject results from _dartToJObject(), leading to native memory leaks.

 

[cursor]

Bug: Silent Failures in Breadcrumb Method

The addBreadcrumb method silently returns when nativeOptions or nativeBreadcrumb are null, bypassing error logging. This behavior is inconsistent with the intent to log failures rather than failing silently.

 

[github-actions]

iOS Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1240.08 ms	1250.15 ms	10.06 ms
Size	5.53 MiB	6.01 MiB	488.15 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
32914d8	1275.47 ms	1285.20 ms	9.73 ms
a10aff4	1241.67 ms	1255.02 ms	13.35 ms
e04b24b	1230.22 ms	1233.90 ms	3.67 ms
40c8f93	1234.27 ms	1261.98 ms	27.71 ms
cf443d2	1255.79 ms	1248.38 ms	-7.40 ms
aeb02f2	1244.29 ms	1256.55 ms	12.26 ms
0fb3800	1256.60 ms	1266.28 ms	9.68 ms
944b773	1252.82 ms	1254.08 ms	1.27 ms
827bf09	1261.86 ms	1276.41 ms	14.55 ms
8541716	1270.18 ms	1271.80 ms	1.62 ms

App size

Revision	Plain	With Sentry	Diff
32914d8	7.86 MiB	9.44 MiB	1.58 MiB
a10aff4	5.53 MiB	6.00 MiB	486.71 KiB
e04b24b	5.53 MiB	6.00 MiB	480.00 KiB
40c8f93	5.53 MiB	6.00 MiB	479.94 KiB
cf443d2	5.53 MiB	6.00 MiB	479.99 KiB
aeb02f2	7.86 MiB	9.44 MiB	1.58 MiB
0fb3800	7.86 MiB	9.44 MiB	1.58 MiB
944b773	5.53 MiB	6.00 MiB	479.98 KiB
827bf09	7.86 MiB	9.44 MiB	1.58 MiB
8541716	5.53 MiB	6.00 MiB	479.96 KiB

Previous results on branch: enh/ffi-jni-breadcrumbs-sync

Startup times

Revision	Plain	With Sentry	Diff
5ad708c	1240.73 ms	1236.33 ms	-4.40 ms
bfb5259	1257.88 ms	1255.78 ms	-2.10 ms
0cfd7ba	1242.02 ms	1239.67 ms	-2.35 ms
1e52e9f	1238.96 ms	1251.20 ms	12.24 ms
a95a359	1270.80 ms	1266.96 ms	-3.84 ms
a2fda2c	1260.47 ms	1255.32 ms	-5.15 ms
d5857e8	1255.33 ms	1256.29 ms	0.96 ms
3a25e45	1255.56 ms	1253.44 ms	-2.12 ms
d4641f9	1248.19 ms	1257.45 ms	9.26 ms
5cc9c78	1240.42 ms	1241.86 ms	1.44 ms

App size

Revision	Plain	With Sentry	Diff
5ad708c	5.53 MiB	6.00 MiB	485.58 KiB
bfb5259	5.53 MiB	6.01 MiB	487.41 KiB
0cfd7ba	5.53 MiB	6.00 MiB	485.59 KiB
1e52e9f	5.53 MiB	6.01 MiB	488.22 KiB
a95a359	5.53 MiB	6.01 MiB	488.13 KiB
a2fda2c	5.53 MiB	6.00 MiB	485.62 KiB
d5857e8	5.53 MiB	6.01 MiB	487.41 KiB
3a25e45	5.53 MiB	6.00 MiB	486.54 KiB
d4641f9	5.53 MiB	6.00 MiB	485.59 KiB
5cc9c78	5.53 MiB	6.00 MiB	486.52 KiB

[github-actions]

Android Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	412.16 ms	401.08 ms	-11.08 ms
Size	13.93 MiB	15.06 MiB	1.13 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
5b9a0da	446.94 ms	449.22 ms	2.28 ms
0929dbf	462.82 ms	492.76 ms	29.94 ms
7b21e8b	467.74 ms	466.24 ms	-1.50 ms
4298701	524.40 ms	633.30 ms	108.90 ms
73dca78	476.53 ms	522.21 ms	45.68 ms
29e8ebe	389.91 ms	395.76 ms	5.84 ms
6b69699	456.06 ms	557.44 ms	101.38 ms
6ba4675	499.80 ms	632.43 ms	132.63 ms
8825ed8	447.65 ms	456.90 ms	9.25 ms
e45c0e1	447.29 ms	558.33 ms	111.04 ms

App size

Revision	Plain	With Sentry	Diff
5b9a0da	13.93 MiB	14.93 MiB	1.00 MiB
0929dbf	6.54 MiB	7.70 MiB	1.17 MiB
7b21e8b	13.93 MiB	15.00 MiB	1.06 MiB
4298701	6.54 MiB	7.71 MiB	1.17 MiB
73dca78	6.54 MiB	7.69 MiB	1.15 MiB
29e8ebe	13.93 MiB	15.06 MiB	1.13 MiB
6b69699	6.54 MiB	7.70 MiB	1.17 MiB
6ba4675	6.54 MiB	7.53 MiB	1015.26 KiB
8825ed8	13.93 MiB	14.93 MiB	1.00 MiB
e45c0e1	6.54 MiB	7.70 MiB	1.16 MiB

Previous results on branch: enh/ffi-jni-breadcrumbs-sync

Startup times

Revision	Plain	With Sentry	Diff
1e52e9f	376.80 ms	364.85 ms	-11.95 ms
bfb5259	436.33 ms	426.84 ms	-9.49 ms
a2fda2c	488.88 ms	482.12 ms	-6.75 ms
d5857e8	453.85 ms	473.59 ms	19.74 ms
5ad708c	414.58 ms	446.49 ms	31.91 ms
054c6ff	416.62 ms	421.02 ms	4.41 ms
5cc9c78	415.94 ms	423.55 ms	7.61 ms
a95a359	418.08 ms	418.00 ms	-0.08 ms
6bcf81b	487.10 ms	490.40 ms	3.30 ms
0cfd7ba	420.21 ms	445.85 ms	25.65 ms

App size

Revision	Plain	With Sentry	Diff
1e52e9f	13.93 MiB	15.06 MiB	1.13 MiB
bfb5259	13.93 MiB	15.06 MiB	1.13 MiB
a2fda2c	13.93 MiB	15.06 MiB	1.13 MiB
d5857e8	13.93 MiB	15.06 MiB	1.13 MiB
5ad708c	13.93 MiB	15.06 MiB	1.13 MiB
054c6ff	13.93 MiB	15.06 MiB	1.13 MiB
5cc9c78	13.93 MiB	15.06 MiB	1.13 MiB
a95a359	13.93 MiB	15.06 MiB	1.13 MiB
6bcf81b	13.93 MiB	15.06 MiB	1.13 MiB
0cfd7ba	13.93 MiB	15.06 MiB	1.13 MiB

[cursor]

Bug: Async Methods Violate FutureOr Declaration

The addBreadcrumb and clearBreadcrumbs methods are declared as FutureOr<void> in ScopeObserver, but their NativeScopeObserver implementations use async. This forces them to always return Future<void>, contradicting the FutureOr declaration. Callers expecting a synchronous result might not await, potentially causing race conditions or unexecuted code.

Additional Locations (2)

• packages/dart/lib/src/scope_observer.dart#L9-L11
• packages/flutter/lib/src/native/sentry_native_channel.dart#L152-L161