Telegram silently routes a copyMessage aimed at a deleted forum topic
into the chat's General topic with NO error, so the bot's error-based
recreate never fired — the user's next message landed in General with no
card. Confirmed against the prod bot logs: a relay after a topic deletion
logged neither "relay to topic failed" nor "topic gone, reopening".
Probe topic liveness before reusing it: re-applying the info card's reply
markup is a no-op that errors only when the card (hence the topic) is
gone, so the bot detects the deletion and reopens the topic + card rather
than relying on the (absent) copy error. The post-copy recreate stays as
a race backstop.
The topic info card built the profile link as `tg://user?id=`, which
clients render as dead text for a user they don't already know (the
test-vs-prod difference an operator saw), and it put the raw display
name through HTML — so a name starting with "/" was auto-detected as a
tappable bot command that fired when tapped.
Render the card with message entities instead: the display name is
covered by a `text_mention` entity (the reliable way to mention a
username-less user the bot has already seen — it messaged the bot),
which links the profile AND, because the name sits inside an entity,
suppresses the "/command" and "@mention" auto-detection on it. Drop the
HTML parse mode and the tg:// link. Entity offsets are UTF-16.
Users who DM the bot anything but /start are relayed into a private
forum supergroup, one topic per user. Operators (the chat's admins)
reply in the topic and the bot copies it back to the user; an info card
opening each topic carries a Block/Unblock toggle and a Clear button.
State is a small JSON file on a new /data volume — the bot host has no
database. Off by default (TELEGRAM_SUPPORT_CHAT_ID=0): the prod bot is
unchanged until the operator sets the chat id and adds the bot as a
forum admin.
- internal/support: concurrency-safe JSON store (topic map, block list,
relayed message ids) with field-targeted mutators and atomic save
- bot/support.go: relay both ways via copyMessage, short-TTL admin
cache, callback buttons, per-user topic-create lock, loop guard
(skip the bot's own posts), reopen a deleted topic on the next message
- config + compose + CI/prod-deploy: TELEGRAM_SUPPORT_CHAT_ID per
contour + TELEGRAM_SUPPORT_STATE_DIR; bot-state named volume; /data
pre-owned by UID 65532 so a fresh volume is writable under distroless
- docs: ARCHITECTURE §15 + decision record, FUNCTIONAL (+ru), README
Ilia Denisov