Session Replay: scope tag (e.g. session_id) not visible / not searchable on Replays (Flutter)

[nguyenthanhphap1413]

Platform

Flutter Mobile iOS, Flutter Mobile Android

Obfuscation

Enabled

Debug Info

Enabled

Doctor

Flutter (Channel stable, 3.29.3, on
macOS 26.3.1 25D771280a
darwin-arm64, locale en-VN)
[1,550ms]
• Flutter version 3.29.3 on channel
stable
• Framework revision ea121f8859 (1
year, 1 month ago), 2025-04-11
19:10:07 +0000
• Engine revision cf56914b32
• Dart version 3.7.2
• DevTools version 2.42.3

Other Error Monitoring Solution

No

Other Error Monitoring Solution Name

No response

Version

sentry_dio: ^9.14.0 sentry_flutter: ^9.14.0 sentry_logging: ^9.14.0

Steps to Reproduce

Environment

SDK: sentry_flutter ^9.14.0 (Dart/Flutter)
Platform: Flutter (iOS/Android — specify which you reproduce on)
Sentry: SaaS (sentry.io) or self-hosted — please specify

We do not have a deterministic, minimal reproduction yet. Below is everything we know so far.

What we observe

• After SentryFlutter.init (with Session Replay sampling set to 1.0), we call Sentry.configureScope and scope.setTag('session_id', ).
• Our application logs confirm this path runs (e.g. “Sentry session ID set: ”).
• In the Sentry product UI, searching Session Replays for tag session_id: does not return the replay we expect for that device/session.

What we have tried

• Confirmed the setTag code runs (logging immediately after configureScope).
• Looked up replays in the Replays view / filters using session_id: (and similar).

Reproducibility

• Intermittent / unclear: we have not isolated exact steps (navigation, timing relative to cold start, background/foreground, etc.) that always lead to “tag missing on replay” vs “works”.
• We are happy to add more instrumentation or try a minimal sample app if you can suggest what would help you narrow it down.

If you need a minimal repro, we can work from a blank Flutter app with sentry_flutter + replay + the same setTag after init, and report whether the tag appears on replays in that case.

Expected Result

Replays for that app session should be findable using the custom tag set on the scope (same as for errors/transactions, or documented equivalent).

Actual Result

The tag does not appear on / is not searchable for Session Replays, even though the scope update appears to succeed locally.

Code sample
await Sentry.configureScope((scope) {
scope.setTag('session_id', sessionId);
});

Are you willing to submit a PR?

None

[linear-code]

DART-368

[buenaflor]

Thanks for the issue, we'll have a look

[buenaflor]

cc @denrase

[denrase]

Suspected un-awaited setTag as the possible culprit, but could not reproduce it. I create a sample app which sets the tag directly after init, with delay, or awaited. All three had the session_id set and were searchable. Ran it on a iOS simulator with both sentry_flutter 9.20.0 and 9.14.0

Here's the sample app: replay_tag_repro.dart.zip

Usage:

cd packages/flutter/example

fvm flutter run \
  -t replay_tag_repro.dart \
  --dart-define=SENTRY_DSN=<your-dsn>

Run with delayed setTag:

fvm flutter run \
  -t replay_tag_repro.dart \
  --dart-define=SENTRY_DSN=<your-dsn> \
  --dart-define=TAG_DELAY_SECONDS=10

Run with awaited setTag:

fvm flutter run \
  -t replay_tag_repro.dart \
  --dart-define=SENTRY_DSN=<your-dsn> \
  --dart-define=REPRO_MODE=awaited

@nguyenthanhphap1413 Any chance you can come up with a setup where this is repoducable?