Add sentry.replay_id to flutter logs

[denrase]

📜 Description

• Add sentry.replay_id to structured logs
• Add sentry._internal.replay_is_buffering to structured logs
• Fixes a bug in test expectations
• Updates native integrations to get scope and non-scope replay id
  • On iOS we only get scope replay id, so right now we cannot determine buffer mode.

💡 Motivation and Context

Closes #3245

💚 How did you test it?

Unit tests

📝 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

---

Note

Add ReplayLogIntegration to enrich Flutter structured logs with replay metadata and include it only on replay-supported platforms, with tests and changelog updates.

• Flutter SDK:
  • Replay log metadata: Introduce ReplayLogIntegration to add sentry.replay_id and sentry._internal.replay_is_buffering to SentryLog via OnBeforeCaptureLog.
  • Default integrations: Add ReplayLogIntegration only when native.supportsReplay is true.
  • Tests:
    • New replay_log_integration_test.dart covering replay id and buffering flag behavior, registration, and cleanup.
    • Update platform integration tests to expect ReplayLogIntegration only on replay-supported platforms.
    • Adjust test/sentry_flutter_util.dart assertion to check by runtimeType for absent integrations.
  • Changelog: Document enhancement under Unreleased.

^{Written by Cursor Bugbot for commit 02f86c3. This will update automatically on new commits. Configure here.}

[codecov]

Codecov Report

❌ Patch coverage is 93.75000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.58%. Comparing base (2b5e090) to head (7980011).

Files with missing lines	Patch %	Lines
...ckages/flutter/lib/src/native/c/sentry_native.dart	0.00%	1 Missing ⚠️
.../flutter/lib/src/native/sentry_native_channel.dart	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3257      +/-   ##
==========================================
+ Coverage   88.22%   89.58%   +1.36%     
==========================================
  Files         294      100     -194     
  Lines       10209     3553    -6656     
==========================================
- Hits         9007     3183    -5824     
+ Misses       1202      370     -832     

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

[github-actions]

Android Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	446.45 ms	422.98 ms	-23.47 ms
Size	13.93 MiB	15.06 MiB	1.13 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
3615e19	468.38 ms	504.71 ms	36.33 ms
8541716	437.14 ms	443.65 ms	6.51 ms
de377fd	572.35 ms	589.21 ms	16.87 ms
6ba4675	499.80 ms	632.43 ms	132.63 ms
4298701	524.40 ms	633.30 ms	108.90 ms
8825ed8	447.65 ms	456.90 ms	9.25 ms
c8596a6	474.00 ms	492.96 ms	18.96 ms
eca355d	485.50 ms	569.85 ms	84.35 ms
b6c8720	457.41 ms	519.04 ms	61.63 ms
944b773	470.54 ms	480.18 ms	9.64 ms

App size

Revision	Plain	With Sentry	Diff
3615e19	6.54 MiB	7.70 MiB	1.16 MiB
8541716	13.93 MiB	15.00 MiB	1.06 MiB
de377fd	6.54 MiB	7.71 MiB	1.17 MiB
6ba4675	6.54 MiB	7.53 MiB	1015.26 KiB
4298701	6.54 MiB	7.71 MiB	1.17 MiB
8825ed8	13.93 MiB	14.93 MiB	1.00 MiB
c8596a6	6.54 MiB	7.53 MiB	1015.27 KiB
eca355d	6.54 MiB	7.70 MiB	1.16 MiB
b6c8720	6.54 MiB	7.69 MiB	1.15 MiB
944b773	13.93 MiB	15.00 MiB	1.06 MiB

Previous results on branch: enha/logs-replay-id

Startup times

Revision	Plain	With Sentry	Diff
f98c32f	479.02 ms	466.78 ms	-12.25 ms
a279e8d	412.42 ms	414.10 ms	1.69 ms
9e888b6	460.09 ms	462.35 ms	2.26 ms
91562e2	464.50 ms	455.70 ms	-8.80 ms
1e63021	430.72 ms	453.78 ms	23.06 ms
234bb86	453.89 ms	457.28 ms	3.39 ms
744d429	452.46 ms	460.69 ms	8.23 ms
02f86c3	453.09 ms	454.63 ms	1.55 ms

App size

Revision	Plain	With Sentry	Diff
f98c32f	13.93 MiB	15.00 MiB	1.06 MiB
a279e8d	13.93 MiB	15.06 MiB	1.13 MiB
9e888b6	13.93 MiB	15.00 MiB	1.06 MiB
91562e2	13.93 MiB	15.00 MiB	1.06 MiB
1e63021	13.93 MiB	15.00 MiB	1.06 MiB
234bb86	13.93 MiB	15.00 MiB	1.06 MiB
744d429	13.93 MiB	15.00 MiB	1.06 MiB
02f86c3	13.93 MiB	15.00 MiB	1.06 MiB

[github-actions]

iOS Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1246.08 ms	1262.00 ms	15.92 ms
Size	5.53 MiB	6.00 MiB	487.07 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
827bf09	1261.86 ms	1276.41 ms	14.55 ms
6bcdc99	1257.16 ms	1264.96 ms	7.79 ms
0fb3800	1256.60 ms	1266.28 ms	9.68 ms
cf443d2	1255.79 ms	1248.38 ms	-7.40 ms
81f83eb	1259.53 ms	1273.39 ms	13.86 ms
73a3c38	1263.37 ms	1277.90 ms	14.53 ms
54acf91	1257.65 ms	1277.96 ms	20.31 ms
a10aff4	1241.67 ms	1255.02 ms	13.35 ms
32914d8	1275.47 ms	1285.20 ms	9.73 ms
7b21e8b	1256.79 ms	1267.12 ms	10.33 ms

App size

Revision	Plain	With Sentry	Diff
827bf09	7.86 MiB	9.44 MiB	1.58 MiB
6bcdc99	5.53 MiB	6.00 MiB	479.95 KiB
0fb3800	7.86 MiB	9.44 MiB	1.58 MiB
cf443d2	5.53 MiB	6.00 MiB	479.99 KiB
81f83eb	7.86 MiB	9.44 MiB	1.58 MiB
73a3c38	7.86 MiB	9.44 MiB	1.58 MiB
54acf91	20.70 MiB	22.46 MiB	1.75 MiB
a10aff4	5.53 MiB	6.00 MiB	486.71 KiB
32914d8	7.86 MiB	9.44 MiB	1.58 MiB
7b21e8b	5.53 MiB	6.00 MiB	479.96 KiB

Previous results on branch: enha/logs-replay-id

Startup times

Revision	Plain	With Sentry	Diff
1e63021	1244.62 ms	1246.37 ms	1.76 ms
744d429	1254.51 ms	1254.19 ms	-0.32 ms
f98c32f	1256.22 ms	1265.67 ms	9.44 ms
9e888b6	1247.65 ms	1245.32 ms	-2.33 ms
91562e2	1242.54 ms	1254.08 ms	11.54 ms
234bb86	1241.00 ms	1250.87 ms	9.88 ms
02f86c3	1262.54 ms	1263.67 ms	1.13 ms
a279e8d	1254.24 ms	1251.52 ms	-2.72 ms

App size

Revision	Plain	With Sentry	Diff
1e63021	5.53 MiB	6.00 MiB	483.21 KiB
744d429	5.53 MiB	6.00 MiB	483.36 KiB
f98c32f	5.53 MiB	6.00 MiB	483.36 KiB
9e888b6	5.53 MiB	6.00 MiB	483.21 KiB
91562e2	5.53 MiB	6.00 MiB	480.92 KiB
234bb86	5.53 MiB	6.00 MiB	479.96 KiB
02f86c3	5.53 MiB	6.00 MiB	480.79 KiB
a279e8d	5.53 MiB	6.00 MiB	487.08 KiB

[denrase]

@stefanosiano Same here, review pls :)

[stefanosiano]

looks good, but i'll put it on hold, until the last point has been decided on: https://www.notion.so/sentry/Logs-Replays-Notes-2738b10e4b5d8035b027c6cb0fc57174
TLDR: when replay is in buffering mode, we'd send a replay id even if the replay is not sent. There is a discussion on what to do

[stefanosiano]

@denrase decision was made
We are going to add a sentry._internal.replay_is_buffering if replay is in buffer mode, and we don't send it if replay is not sampled or in session mode.

Then we keep the sentry.replay_id flag as you already did in this PR 👍

[denrase]

@stefanosiano Pls take a look if i interpreted the flag correctly.

[stefanosiano]

@denrase
The logic should be this:

1. Session replay is running -> set sentry.replay_id
2. Buffer replay is running -> set sentry.replay_id and sentry._internal.replay_is_buffering
3. No replay is running -> don't set anything

In Android we have this distinction because the replay id is set in the scope when the replay is captured (and it's in session mode), and is only available in the replay integration (and not in the scope) when it's running in buffer mode.
Can we do something similar here?
Also, why are you creating a new integration if you can check it directly in the client in captureLog()?

[denrase]

@stefanosiano Thank you, didn't have access to SentryFlutterOptions in captureLog

[stefanosiano]

Thank you, didn't have access to SentryFlutterOptions in captureLog

i guess it's fine if you try to cast the options of the scope to SentryFlutterOptions.
At least the logic of enhancing the logs is not scattered in different classes, imho

[denrase]

@stefanosiano AFAIK this only works in the Flutter repo, as the Dart repo does not know about the SentryFlutterOptions class at all.

[stefanosiano]

@stefanosiano AFAIK this only works in the Flutter repo, as the Dart repo does not know about the SentryFlutterOptions class at all.

yeah right

[denrase]

@stefanosiano Took me a while to debug this and figure out how everything fits together. We have the following issues:

• On iOS we read the replay ID from the Scope, but do not have access to an internal/integration ID, so we cannot reliably tell if we are in buffer mode. This is called continuously for every screenshot.

• On Android we get the replay ID from the integration, which we set to the scope, so it's immediately set, even when in buffer mode. This is called once when the recorder is starting.

So the latter is currently incorrect I think. Need to think about how we wan't to tackle this.

\cc @buenaflor

[buenaflor]

@denrase sounds like we need some internal hybrids SDK api from cocoa for this

[buenaflor]

I think it might be good to align with RN here

[denrase]

@buenaflor Checked RN. Right now they are only setting the replay_id without buffering info.

https://github.com/getsentry/sentry-react-native/blob/0b647531c13884b6be72c6f652482d79c6d2d96f/packages/core/src/js/integrations/logEnricherIntegration.ts#L91

[buenaflor]

@buenaflor Checked RN. Right now they are only setting the replay_id without buffering info.

is sentry._internal.replay_is_buffering a strict requirement right now? or should we move forward without it and handle this in another PR?

[denrase]

@buenaflor On Android this works as expected AFAIK, on iOS we can only detect full sessions or onError sessions as soon as they are set to the scope. @stefanosiano Do you know if this would be ok as a step between? RN also only sets replay_id without buffering info, though i did not check if this is already released.

[github-actions]

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