Preserve original message timestamps through fork/compress/branch#28840
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yitang wants to merge 2 commits into
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Preserve original message timestamps through fork/compress/branch#28840yitang wants to merge 2 commits into
yitang wants to merge 2 commits into
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messages.timestamp is always time.time() at INSERT time. When messages are
copied between sessions during /branch, compression, or /retry, their
original timestamps are silently discarded.
This change adds an optional timestamp parameter to append_message() and
reads msg.get('timestamp') in replace_messages(), then forwards it from
every caller that has the field available.
All changes are backward compatible: callers that do not pass timestamp
get identical time.time() behaviour.
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… stronger fork test
This was referenced May 19, 2026
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Preserve original message timestamps through fork/compress/branch
Summary
messages.timestampis alwaystime.time()at INSERT time. When messages arecopied between sessions during
/branch, compression, or/retry, theiroriginal timestamps are silently discarded. This change adds an optional
timestampparameter toappend_message()and readsmsg.get("timestamp")in
replace_messages(), then forwards it from every caller that has the fieldavailable.
All changes are backward compatible: callers that don't pass
timestampgetidentical
time.time()behaviour.Changes
hermes_state.pyappend_message(): added optionaltimestamp: float = Noneparam; uses it instead oftime.time()when set.replace_messages(): readsmsg.get("timestamp")per message, falls back totime.time()run_agent.pytimestamp=msg.get("timestamp")in_flush_messages_to_session_db()gateway/run.pytimestamp=msg.get("timestamp")in/branchhandlercli.pytimestamp=msg.get("timestamp")in branch handlertui_gateway/server.pytimestamp=msg.get("timestamp")in branch handlergateway/session.pytimestamp=message.get("timestamp")inappend_to_transcript()gateway/mirror.pytimestamp=message.get("timestamp")in_append_to_sqlite()tests/test_hermes_state.pyTestTimestampPreservationwith 8 testsAll 8 files: each caller forwards
msg.get("timestamp")toappend_message()or
replace_messages(). The core fix inhermes_state.py(accept + store thesupplied timestamp) makes every caller work correctly — both the ones modified here
and existing ones using
replace_messages()with timestamp-bearing dicts.Backward compatibility
timestamp=None(default) →time.time()as before.timestampis keyword-onlywith default.
replace_messages()falls back tobase_ts = time.time()when a messagedict has no
timestampkey.Testing
8 new tests in
tests/test_hermes_state.py::TestTimestampPreservation:test_append_message_with_explicit_timestamptest_append_message_multiple_timestampstest_append_message_without_timestamp_defaultstime.time()fallbacktest_append_message_mixed_timestampstest_replace_messages_preserves_timestampsreplace_messagestest_replace_messages_fallback_when_no_timestamptest_replace_messages_mixed_timestampstest_fork_chain_preserves_timestamps/branchcopy preserves original timestampsImplementation notes
The root cause was narrow:
append_message()never accepted a caller-supplied timestamp → 1 param + 1 conditionalreplace_messages()never read timestamps from dicts → 3 lines changedThe 6 callers (branch handlers, mirror, flush, transcript) all needed a 1-line
forwarding change. Existing callers using
replace_messages()withtimestamp-bearing dicts (
rewrite_transcript, ACP persist) worked automaticallyonce the core fix was in place.