## Summary
Fixes a bug where interrupting a streaming chat and sending a new
message
left the relay connected to the wrong replica. Expanded into a broader
refactor that cleanly separates concerns:
- **OSS** owns pubsub subscription, message catch-up, queue updates,
status forwarding, and local parts merging.
- **Enterprise** (`enterprise/coderd/chatd`) only manages relay dialing,
reconnection, and stale-dial discarding for cross-replica streaming.
## Architecture
### OSS `coderd/chatd/chatd.go`
`Subscribe()` builds the initial snapshot then runs a single merge
goroutine that handles:
- Pubsub subscription for durable events (status, messages, queue,
errors)
- Message catch-up via `AfterMessageID`
- Local `message_part` forwarding
- Relay events from enterprise (when `SubscribeFn` is set)
- Sends `StatusNotification` to enterprise so it can manage relay
lifecycle
Key types:
- `SubscribeFn` — enterprise hook, returns relay-only events channel
- `SubscribeFnParams` — `ChatID`, `Chat`, `WorkerID`,
`StatusNotifications`, `RequestHeader`, `DB`, `Logger`
- `StatusNotification` — `Status` + `WorkerID`, sent to enterprise on
pubsub status changes
### Enterprise `enterprise/coderd/chatd/chatd.go`
`NewMultiReplicaSubscribeFn(cfg MultiReplicaSubscribeConfig)` returns a
`SubscribeFn` that:
- Opens an initial synchronous relay if the chat is running on a remote
worker
- Reads `StatusNotifications` from OSS to open/close relay connections
- Handles async dial, reconnect timers, stale-dial discarding
- Returns only relay `message_part` events
## Bug fixes
### Original bug: stale relay dial after interrupt
`openRelayAsync` goroutines used `mergedCtx` (subscription-level), not a
per-dial context. `closeRelay()` could not cancel in-flight dials. When
the user interrupts and a new replica picks up the chat, the old dial
goroutine could complete after the new one and deliver a stale
`relayResult`.
**Fix**: per-dial `dialCtx`/`dialCancel`, `expectedWorkerID` tracking,
`workerID` on `relayResult`. `closeRelay()` cancels the dial context and
drains `relayReadyCh`. Merge loop rejects mismatched worker IDs.
### Additional fixes
- `statusNotifications` send-on-closed-channel race — goroutine now owns
`close()` via defer
- Enterprise spin-loop on `StatusNotifications` close — two-value
receive
with nil-out
- `hasPubsub` set from `p.pubsub != nil` instead of subscription success
— now tracks actual subscription result
- `lastMessageID` not initialized from `afterMessageID` — caused
duplicate messages on catch-up
- `wrappedParts` goroutine leaked remote connection on `dialCtx` cancel
- `closeRelay()` did not drain `relayReadyCh`
- `setChatWaiting` race with `SendMessage(Interrupt)` — wrapped in
`InTx`
- `processChat` post-TX side effects fired when chat was taken by
another
worker — added `errChatTakenByOtherWorker` sentinel
- Cancel closure data race on `reconnectTimer`
- Bare blocking send on pubsub error path
- `localParts` hot-spin after channel close
- No-pubsub branch dropped relay events and initial snapshot
- Failed relay dial caused permanent stall (no reconnect retry)
- DB error during reconnect timer caused permanent stall
- `time.NewTimer` replaced with `quartz.Clock` for testable timing
## Tests
9 enterprise tests covering:
- Relay reconnect on drop (mock clock)
- Async dial does not block merge loop
- Relay snapshot delivery
- Stale dial discarded after interrupt
- Cancel during in-flight dial
- Running-to-running worker switch
- Failed dial retries (mock clock)
- Local worker closes relay
- Multiple consecutive reconnects (mock clock)
All pass with `-race`.
Despite the SDK type having an `Archived` field for chats, this data was
never fetched from the database — the `GetChatsByOwnerID` query
hardcoded `AND archived = false`, and the `convertChat` function never
mapped the field.
This PR adds an optional `archived` query parameter to `GET
/api/experimental/chats`:
| Value | Behavior |
|-------|----------|
| *(not provided)* | Returns all chats (active and archived) |
| `archived=false` | Returns only non-archived chats |
| `archived=true` | Returns only archived chats |
This follows the same pattern used by template versions
(`sqlc.narg('archived')` nullable boolean).
Also fixes `convertChat` to populate the `Archived` field in API
responses, which was never being set despite existing on the SDK type.
## Summary
Remove the `workspace_agent_id` column from the `chats` table and
dynamically look up the first workspace agent instead.
## Problem
When a workspace is stopped and restarted, the workspace agent gets a
new ID. The `workspace_agent_id` stored on the chat at creation time
becomes stale, making the agent unreachable. This caused chats to break
after workspace restarts.
## Solution
Instead of persisting the agent ID, dynamically look up the first agent
from the workspace's latest build via
`GetWorkspaceAgentsInLatestBuildByWorkspaceID` whenever an agent
connection is needed. The `workspace_id` on the chat remains stable
across restarts.
This behavior may be refined later (e.g., agent selection heuristics),
but picking the first agent resolves the immediate breakage.
## Changes
- **Migration 000425**: Drop `workspace_agent_id` column from `chats`
- **SQL queries**: Remove `workspace_agent_id` from `InsertChat` and
`UpdateChatWorkspace`
- **chatd.go**: `getWorkspaceConn` and `resolveInstructions` now look up
agents dynamically from workspace ID
- **chatd.go**: Remove `refreshChatWorkspaceSnapshot` (no longer needed)
- **createworkspace.go**: Stop persisting agent ID when associating
workspace with chat
- **subagent.go**: Stop passing agent ID to child chats
- **SDK/frontend**: Remove `WorkspaceAgentID` / `workspace_agent_id`
from Chat type
---------
Co-authored-by: Kyle Carberry <kylecarbs@gmail.com>
Adds a nullable `last_error` column to the `chats` table so error
reasons survive page reloads.
**Backend:**
- Migration adds `last_error TEXT` (nullable) to chats
- `UpdateChatStatus` writes the error reason when status transitions to
`error`, clears it (NULL) on recovery
- `convertChat` maps `sql.NullString` to `*string` in the SDK
**Frontend:**
- Sidebar falls back to `chat.last_error` when no stream error reason is
cached
- Chat detail page does the same for `persistedErrorReason`
- Fixtures updated for new required field
## Summary
The UI has always labeled the action as "Archive agent" but the backend
was performing a hard `DELETE`, permanently destroying chats and all
their messages.
This change replaces the hard delete with a soft archive, consistent
with the pattern used by template versions.
## Changes
### Database
- **Migration 000423**: Add `archived boolean DEFAULT false NOT NULL`
column to `chats` table
- Replace `DeleteChatByID` query with `ArchiveChatByID` (`UPDATE SET
archived = true`)
- Add `UnarchiveChatByID` query (`UPDATE SET archived = false`)
- Filter archived chats from `GetChatsByOwnerID` (`WHERE archived =
false`)
### API
- Remove `DELETE /api/experimental/chats/{chat}`
- Add `POST /api/experimental/chats/{chat}/archive` — archives a chat
and all its descendants
- Add `POST /api/experimental/chats/{chat}/unarchive` — unarchives a
single chat (API only, no UI yet)
### Backend
- `archiveChatTree()` recursively archives child chats (replaces
`deleteChatTree()` which hard-deleted)
- Chat daemon's `ArchiveChat()` archives the full chat tree in a
transaction
- Authorization uses `ActionUpdate` instead of `ActionDelete`
### SDK
- Replace `DeleteChat()` with `ArchiveChat()` and `UnarchiveChat()`
- Add `Archived` field to `Chat` struct
### Frontend
- `archiveChat` API call uses `POST .../archive` instead of `DELETE`
- No UI changes — the "Archive agent" button now actually archives
instead of deleting
## Design Decision
This follows the **template version archive pattern** (Pattern B in the
codebase):
- `archived boolean` column (not `deleted boolean`)
- Dedicated `POST .../archive` and `POST .../unarchive` routes (not
repurposing `DELETE`)
- Reversible — users can unarchive via the API (UI for this will come
later)
Kyle Carberry