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fix(matrix): skip events received before bot startup - #3575
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Re-bin merged 1 commit intoMay 1, 2026
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Matrix sync replays the room timeline on each startup or `/restart`, causing already-handled messages to be reprocessed (HKUDS#3553). Even with `store_sync_tokens=True`, the sync token isn't reliably re-injected when restoring a session via access_token + load_store(), so the client re-reads recent timeline entries. Filter `event.server_timestamp` against the process start time so old events are dropped at the `_on_message` / `_on_media_message` entry points. Trade-off: messages received during downtime won't be processed, which matches the issue reporter's expectation. Closes HKUDS#3553 Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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This is the right fix for Matrix startup replay.
The timestamp guard is narrow: it only skips events whose server_timestamp predates this process start, and it applies before typing/message handling for both text and media paths. The tests cover both entry points.
I merged latest main locally and ran uv run --extra matrix pytest tests/channels/test_matrix_channel.py: 64 passed.
Ready to merge.
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Summary
Closes #3553 — Matrix channel reads old messages on startup /
/restart.self._started_at_mswhenstart()runs.server_timestamp < _started_at_msat the entry of_on_messageand_on_media_message._is_pre_startup_event(event)helper to keep the policy in one place.Why
Matrix sync replays the room timeline on each startup. Even with
store_sync_tokens=Truethe sync token is not reliably re-injected when a session is restored viaaccess_token+load_store()(vs full login), so the client re-reads recent timeline entries and_on_messagefires for already-handled messages — exactly the symptom reported in #3553.A timestamp guard is independent of sync-token state and matches the standard pattern used by matrix-nio bot examples. Trade-off: messages received while the bot is down won't be processed, which is what the issue reporter expects ("already read messages should not be interpreted again").
Test plan
pytest tests/channels/test_matrix_channel.py— 64 passedtest_on_message_skips_pre_startup_eventcovers text pathtest_on_media_message_skips_pre_startup_eventcovers media pathserver_timestampcontinue to be processed because_started_at_msdefaults to0andgetattrreturnsNone)🤖 Generated with Claude Code