Live DM testing showed a reply to a DM cron brief did NOT continue the job.
Root cause: for a 1:1 DM the governing knob is dm_top_level_threads_as_sessions
(default True), NOT reply_in_thread / cron_continuable_surface. Under the
default, each top-level DM keys to a per-message session (…:dm:<chat>:<ts>),
so a reply mints a new ts and can never converge with the flat …:dm:<chat>
session the cron seed creates.
A 1:1 DM has no thread-vs-timeline split, so "in_channel" has no coherent
meaning for a DM — cron_continuable_surface is a channel concept and is a
no-op for DMs. DM continuation is governed entirely by
dm_top_level_threads_as_sessions:
- false → all top-level DMs share …:dm:<chat> → seed + reply converge → works
- true (default) → per-message sessions → no continuation (cron or interactive)
Option A (chosen): document the requirement; no code change (the flat-DM seed
from the prior commit already lands correctly when the knob is false). Adds a
":::note 1:1 DMs" admonition to cron.md + the zh-Hans mirror.
Verification (real inbound handler, not a hard-coded assumption — the mistake
that made the earlier DM E2E falsely pass): tests/manual/cron_inchannel_dm_e2e.py
drives the REAL _handle_slack_message for a top-level DM under both knob values
and asserts false→converges (…:dm:D_TESTDM == seed), true→diverges
(…:dm:D_TESTDM:<ts>). See decisions.md D9.
Live testing exposed a real bug: an in_channel continuable cron delivered
flat to the channel (✅) but the reply did NOT continue the job — the bot
had no brief in context and confabulated the answer.
Root cause: mirror_to_session only APPENDS to a session that already
exists (_find_session_id → no-op when none matches); it never CREATEs one.
A flat (slack, chat_id, None) row is only created when a human posts a
top-level message the bot processes — a cron chat_postMessage delivery
never goes through the inbound handler, so the row is absent and the brief
is silently dropped. The prior impl relied on the bare mirror (F5/OQ-1
concluded "deletion only" — wrong).
Fix: _seed_cron_channel_session mirrors _seed_cron_thread_session —
get_or_create_session FIRST (chat_type = "dm" if is_dm else "group",
thread_id=None), keyed to the ORIGIN USER'S id, then mirror. The channel
session key embeds user_id (…:group:<chat>:<user>), so a system:cron id
would key the seed away from the reply; the origin user's id makes seed
key == inbound reply key. DM key ignores user_id but needs chat_type=dm
to match the prefix. Wired into the in_channel branch after delivery;
suppresses the generic mirror to avoid double-write.
DM validated (per request): the seeded key equals the inbound DM reply key
for a 1:1 DM; continuation works there too.
Tests:
- Rewrote the in_channel tests to use a real _session_store and the origin
user_id; assert get_or_create_session is called with the flat, correctly-
keyed source. Prove-fail: (a) reverting the create step and (b) seeding
with system:cron each turn a targeted test RED; restore → GREEN.
- +2 direct _seed_cron_channel_session unit tests asserting the KEY-MATCH
invariant (seed key == inbound reply key) via build_session_key, for both
channel and DM.
- Rewrote tests/manual/cron_inchannel_e2e.py to drive a REAL SessionStore +
real mirror_to_session + real _find_session_id + real build_session_key
(no session-layer mocks — the old mocked E2E is exactly why the bug
shipped). Asserts the brief lands in the transcript and the reply resolves
to the same session, for BOTH channel and 1:1 DM.
Full relevant sweep: 283 passed.
Add a per-platform `cron_continuable_surface` extra key
(`thread` default | `in_channel`) so a continuable cron job can deliver
FLAT into a Slack channel — no dedicated thread — and still be
replied-to. In `in_channel` mode the scheduler skips the thread-open
branch (leaves `thread_id=None`); the shipped origin-mirror then seeds
the `(slack, chat_id, None)` shared-channel session — the same bucket
`reply_in_thread: false` routes inbound channel replies to — so a plain
channel reply continues the job in context.
Design: specs/cron-inchannel-continuable (D1–D7, F5). Model B
(shared-channel session), NOT anchoring to the delivery `ts` — on Slack
replying to a specific message IS threading, so a `ts` anchor would only
relocate the thread, never deliver true threadless continuable.
- gateway/platforms/base.py: `supports_inchannel_continuable` capability
flag (default False → unsupported platforms fail SAFE to `thread`).
- plugins/platforms/slack/adapter.py: flag=True; `_cron_continuable_surface()`
resolver (coerces to the two-value enum); `_warn_if_inchannel_without_flat_reply`
connect-time warning (D5: warn, not hard-require — the misconfig fails safe).
- gateway/config.py: shared-key bridge line (top-level OR nested config).
- cron/scheduler.py: read the key generically from platform config, gate
the `in_channel` branch on the adapter capability flag, skip thread-open.
No new seed function (reuses the existing mirror — G6).
Pairing (docs): `in_channel` + `reply_in_thread: false` +
`require_mention: false` (or a free-response channel). Missing
`reply_in_thread: false` fails safe to a threaded continuation.
Gateway-side config flag — `/restart` to apply; NO Slack app reinstall.
Tests (from inside the worktree, PYTHONPATH=$PWD):
- +6 cron scheduler tests (in_channel skips thread-open; seeds flat
channel session with thread_id=None; thread-mode regression;
fail-safe on unsupported platform; value coercion). Prove-fail:
removing the `and not in_channel_surface` guard turns the two
load-bearing tests RED; restore → GREEN.
- +10 slack resolver/capability/warning tests; +2 config-bridge tests.
- tests/manual/cron_inchannel_e2e.py: offline E2E driving BOTH real
legs (delivery seed + inbound reply keying) → both converge on
(slack, C, None).
- No regressions: test_slack.py 216 passed alone; broader sweep green
(4 pre-existing cross-file-ordering failures reproduce identically on
pristine origin/main).
Docs: cron.md + slack.md + zh-Hans mirrors of both.
