Replay flush followed by immediate stop deletes the buffered video #6247

Integration

sentry-android

Build System

Gradle

AGP Version

9.1.0

Proguard

Disabled

Other Error Monitoring Solution

No

Version

8.60.0

Steps to Reproduce

1. Initialize SentryAndroid with both Replay sample rates set to 0.
2. While the Activity is visible, run:

Sentry.replay().startBuffering()
Handler(Looper.getMainLooper()).postDelayed({
    Sentry.replay().flush()
    Sentry.replay().stop()
}, 5_000)

Reproduced on a Pixel 6a emulator running Android 13, using the default native recorder in a plain Android Activity without a Flutter engine or bridge. Also reproduced through Flutter.

Expected Result

Stop preserves the video from the requested flush so its queued envelope can be serialized.

Actual Result

Segment 0 uploads with zero video bytes. Adding a 10-second delay before stop uploads segment 0 with 15,039 video bytes in the native reproduction.

Flush creates 0.mp4, but immediate stop can attempt segment 0 again with no frames because the asynchronous callback advancing the converted session's segment ID is skipped after stop.

ReplayCache.createVideoOf() deletes the existing output before checking for empty frames, removing the flushed video before transport reads it. Native diagnostics during the Flutter reproduction confirmed deletion of the existing 4,394-byte file.

Suggested fix: Move output-file deletion below the empty-frame guard and add a regression test preserving an existing video. A temporary native guard made the Flutter reproduction pass with 4,394 video bytes. Segment-ID reuse also needs investigation; this guard addresses the confirmed empty-frame deletion.

Related: getsentry/sentry-dart#4071. This is a separate deletion path from the fix in #6177.