fix(session_exec): stop duplicate session:start for raw sessions — emit session:config instead - #79
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…tart for raw mode
Root cause (Bug 2):
When session.raw=True, the Rust kernel emits session:start once (the
base event), then calls emit_raw_field_if_configured() which emitted
session:start a SECOND TIME with the raw config payload. Every session
with raw=True got two session:start events per execute() call, separated
by 13+ seconds (the time for redact_secrets() on a 900KB+ config and
hook dispatch overhead).
Fix:
Change emit_raw_field_if_configured() to emit 'session:config' instead
of re-emitting the base event (session:start or session:resume). The
raw config payload is now in a dedicated event. Consumers that need the
raw mount plan should subscribe to 'session:config'.
The 'event_base' parameter is retained for API compatibility but is no
longer used as the emitted event name.
Performance impact:
The 13s startup delay (observed in sessions 98320ded and 69ab20de) came
from hook chains processing a 900KB session:start payload twice. With
this fix, the raw config is emitted as session:config (still slow for
large configs, but at least it's not mistaken for a lifecycle event).
Migration:
Downstream consumers (e.g. hook-context-intelligence) that read the raw
config from session:start must now subscribe to session:config.
Tests:
- test_session_start_dedup.py (new): 4 tests asserting
1. session:start emitted exactly once for raw sessions
2. session:config emitted with raw payload
3. session:start still emitted (guard against over-correction)
4. non-raw sessions unaffected (still emit session:start exactly once)
Brian Krabach (bkrabach)
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Summary
Bug 2 from session lifecycle investigation: when
session.raw=True, every call toexecute()was emitting twosession:startevents separated by 7–13 seconds:session:start(small payload, no raw config)emit_raw_field_if_configured()emits a secondsession:startwith the full 900KB+ raw configThe 13s gap is the time for
redact_secrets(config)on a massive config + hook dispatch overhead.Root Cause
_session_exec.py::emit_raw_field_if_configured()was designed to emit the raw config on the base session event name (session:start,session:resume). But the Rust kernel already emitted the base event synchronously before calling this helper, so both emits hit the samesession:startevent type.Fix
Change
emit_raw_field_if_configured()to emitsession:configinstead of re-emittingsession:start. The raw mount plan is now in a dedicated event.API compatibility: The
event_baseparameter is retained in the function signature but is no longer used as the event name.Migration
Downstream consumers that read raw config from
session:startmust subscribe tosession:configinstead. Known affected systems:hook-context-intelligence— reads raw session config for graph enrichment (separate PR needed)Evidence
Observed in sessions
3dca44c1and69ab20defrombehavior-provenanceworkspace:After fix: single
session:start+ separatesession:configevent.TDD Red-Green Cycle
RED (before fix):
test_session_start_emitted_exactly_once_for_raw_mode→ FAILED (count=2)test_raw_config_captured_in_session_config_event→ FAILED (no session:config event)GREEN (after fix):
Files Changed
python/amplifier_core/_session_exec.pyevent_baseto"session:config"bindings/python/tests/test_session_start_dedup.pyTest Results