Drop the message_count > 0 guard — if it's 0 in the DB (stale metadata,
race condition, failed persist), the session stays empty and the model
gets no conversation history. The UI history endpoint has its own DB
fallback, so messages display correctly but never reach the LLM.
Now hydrate from DB whenever history is empty, regardless of message_count.
Trade-off: one extra DB query for genuinely empty sessions (rare).
_parse_msg_content deserializes stored multimodal content (image/audio
blocks) back into a list. It treated ANY string starting with '[{' and
containing the substring "type" as serialized content, requiring only
that each element be a dict — never that "type" be a real content-block
kind. So a plain text message whose content happens to be a JSON array
of typed objects (e.g. a user pasting an API schema sample like
[{"type": "object", ...}]) was silently parsed from str into a list on
the next hydration, destroying the original string. This runs on every
session load from the DB (_db_to_session -> get_session). Restrict the
round-trip to non-empty lists whose every element is a dict whose
"type" is a recognized block kind (text/image/image_url/audio/...);
real multimodal content (verified: document_processor emits exactly
these) still round-trips, JSON-looking text is left untouched.
* docs: add implementation plan for fixing chat context drifting (#135)
* fix: make Session.history immutable + fix {}.history crash
- Session.history now exposes a COPY of the internal _history list
- add_message() replaces history with a fresh copy each time
- get_context_messages() derives from _history directly
- replace_messages() updates both _history and history
- truncate_messages() updates both _history and history
- _persist_message() line 207: fixed {}.history fallback crash
- Added 11 tests for session isolation and edge cases
Addresses #135 root cause #1: shared mutable references
* fix: task scheduler uses SessionManager methods instead of overwriting sessions
- Added ensure_task_session() to SessionManager (checks cache first)
- Task scheduler now uses ensure_task_session() instead of direct dict assignment
- Task scheduler now uses SessionManager.add_message() for message persistence
- Removed direct sess_obj.history.append() that was silently losing data
Addresses #135 root causes #2 and #3
* fix: add age guard to cleanup_empty_sessions — don't delete sessions <1h old
Prevents the cleanup task from deleting sessions that were just created
and haven't received any messages yet (message_count == 0).
Addresses #135 root cause #5
* test: comprehensive session isolation tests (10/10 passing)
* refactor: consolidate _session_manager into singleton pattern
- Added set_session_manager_instance / get_session_manager_instance to core/models
- kept backward-compat aliases (set_session_manager, get_session_manager)
- session_manager.py re-exports the singleton functions
- ai_interaction.set_session_manager now syncs with the core singleton
- context_compactor uses get_session_manager_instance() instead of getattr hack
- app.py initializes the singleton once
Addresses #135 root cause #4: fragile global wiring
* test: add concurrent session isolation integration tests
Verifies:
- Concurrent add_message to different sessions doesn't cross-contaminate
- Rapid parallel writes maintain isolation
- Read-write concurrent access is safe
All 3 async tests pass, proving the immutable history fix works under concurrency
* fix: pre-import core.models in conftest to prevent test pollution
test_agent_loop.py stubs sys.modules['core.models'] = MagicMock() at
module level during collection. Any test collected after it imports
Session as a MagicMock. Pre-importing core.models in conftest.py
before test_agent_loop.py's module-level code runs prevents this.
* fix: make .history authoritative mutable list, address PR review
Per review feedback: keep .history as the authoritative mutable list so
existing code doing .history.pop(), .history = [...], etc. still works.
Fix the cross-contamination bug by ensuring __post_init__() gives each
Session its OWN unique history list (never shared).
Changes:
- core/models.py: .history IS the authoritative list. _history aliases it.
Each Session gets its own list in __post_init__.
- core/session_manager.py: add_message() delegates to Session.add_message()
instead of appending directly — no double-append, single source of truth.
- tests/test_session_manager.py: updated test to reflect that .history
references see new messages (same list, not a snapshot).
- docs/plans/2026-06-01-fix-chat-context-drifting.md: removed (not for
shipping — useful design context but too much process/doc to ship).
All 272 tests pass (3 pre-existing failures unrelated).
* Fix session manager message persistence
* Fix session history alias regressions
* Fix session history aliasing and task delivery
truncate_messages deletes db_messages[keep_count:] (a no-op when
keep_count >= the real message total) then unconditionally wrote
db_session.message_count = keep_count. When keep_count exceeds the
number of messages that actually exist — e.g. the manage_session AI
tool defaults keep_count to 10, and the HTTP truncate endpoint passes
any client value — the persisted count is set too high (10 on a
3-message session), diverging from the real row count. That column
gates lazy DB-hydration in get_session (message_count > 0) and is
surfaced to the history UI, so it is correctness-relevant. Clamp to
min(keep_count, len(db_messages)); the in-memory slice already caps
naturally.
Multimodal content (list of {type, text/image_url} blocks) couldn't be
stored in the DB Text column, causing silent persist failures. On reload
the frontend fell back to String() on the array, rendering
[object Object],[object Object] in the chat.
- Serialize list content as JSON in _persist_message()
- Deserialize back to list in _db_to_session() via _parse_msg_content()
- Extract text parts from multimodal arrays in sessions.js instead of
String() coercion
A session that exists only in the in-memory SessionManager — never persisted,
or whose DB row was removed out-of-band — was listed by GET /api/sessions (the
list is built from the in-memory manager) but 404'd on every per-session
operation, so it could never be deleted.
Two causes, both fixed:
1. _verify_session_owner() only consulted the DB and raised 404 when no row
existed. It now falls back to the in-memory session's owner when (and only
when) a session_manager is supplied and the caller actually owns the ghost.
The DB row stays authoritative when present, and a ghost owned by another
user still 404s, so the ownership/security model is unchanged. The new
parameter defaults to None, preserving behavior for all other callers.
2. SessionManager.delete_session() only removed the in-memory entry when a DB
row was found, so memory-only ghosts survived. It now drops the in-memory
copy regardless and reports success when either the DB row or the in-memory
entry was removed.
Added tests/test_session_ghost_delete.py covering both layers, including the
cross-owner 404, the unauthenticated 403, DB-row-wins precedence, and backward
compatibility when no manager is passed.
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
