Discourse Workflows

j.jaffeux · September 2, 2026, 2:41pm

We have added the following to workflows:

FEATURE: Workflow triggers for event participation and event end (#42634)

committed 10:09AM - 02 Sep 26 UTC

Previously, the events plugin had no way to drive a workflow from an RSVP or fro…m an event finishing, and a trigger node contributed by any plugin was added to the registry but never subscribed to its `DiscourseEvent` — so it saved fine, showed up in the palette, and silently never fired. This change wires the subscription into node registration, which drops the hand-rolled `on(...)` workarounds in assign, topic voting and chat, and adds `trigger:event_participation_changed` and `trigger:event_ended`, both scopable to a single topic. --- Split into two commits, since the first touches shared infrastructure: - **`FIX: Subscribe trigger events for workflow nodes added by plugins`** — claiming a node now registers *and* subscribes it, and contributing plugins are flushed before the host claims its own, so ownership lands on them. Because the subscription goes through `Plugin::Instance#on`, a node stops listening while *its own* plugin is disabled rather than following the host's setting. This also drops a duplicate registration that let `trigger:chat_message_created` show in the palette while chat was disabled. - **`FEATURE: Workflow triggers for event participation and event end`** — the two triggers. No `on(...)` wiring needed in the events plugin thanks to the commit above. Three behaviour changes in the events plugin, each deliberate: - Withdrawing an RSVP destroyed the record without publishing anything, so attendance state built from these triggers could never recover from someone leaving. Removal now publishes, and reads as `status: null` with `removed: true`. The livestream chat sync skips removals, so its follow/unfollow behaviour is unchanged. - The ended occurrence travels with `:discourse_post_event_event_ended`. `set_next_date` moves the event on immediately afterwards, and `Event#starts_at` returns `nil` once a bounded series is past `recurrence_until`, so the event alone cannot say which occurrence ended. - Re-submitting an unchanged RSVP still publishes, so the trigger ignores it rather than running a workflow twice for one decision. Payload is `{event, post, topic, stats}`, plus `{user, participation}` on the participation trigger — modelled on `WebHook.build_calendar_event_payload` rather than `EventSerializer`, which goes admin-truthy under a system guardian. No JS, no core changes, no new site settings. ### Known gaps, documented rather than fixed Bulk invite, `Event#create_invitees` (`insert_all!`), `reset_invitee_notifications` (`update_all`), `enforce_private_invitees!` (`delete_all`) and event/user destroy stay silent. `create_attendance!` swallows `RecordNotUnique`, so a concurrent first RSVP fires nothing. `event_ended` can re-fire if an edit resets `finished_at`, and is missed when an event is closed early: `EventDate.pending` merges `Event.open`, so the in-flight occurrence leaves the job's scope. `EventListener` does not rescue `new`/`valid?`/`matches?` and `DiscourseEvent.trigger` re-raises, so a raising subscriber aborts `MonitorEventDates` mid-`find_each`. Adding `continue_on_error:` there breaks existing `track_events` assertions, so it is left for its own commit. ### Testing Full `discourse-workflows` and `discourse-events` backend suites pass (4005 examples), plus the workflow specs in chat, assign and topic voting. Verified at runtime that all 22 trigger nodes have exactly one subscription and there are no duplicate registrations, and that both new nodes disappear from the palette and stop dispatching when `discourse_events_enabled` is off. Meta: https://meta.discourse.org/t/discourse-calendar-events-webhook-triggers-automations-plugin/409623 --------- Co-authored-by: Joffrey JAFFEUX <j.jaffeux@gmail.com>

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