[feature] Conversations API (#3013)

* Implement conversations API

* Sort and page conversations by last status ID

* Appease linter

* Fix deleting conversations and statuses

* Refactor to make migrations automatic

* Lint

* Update tests post-merge

* Fixes from live-fire testing

* Linter caught a format problem

* Refactor tests, fix cache

* Negative test for non-DMs

* Run conversations advanced migration on testrig startup as well as regular server startup

* Document (lack of) side effects of API method for deleting a conversation

* Make not-found check less nested for readability

* Rename PutConversation to UpsertConversation

* Use util.Ptr instead of IIFE

* Reduce cache used by conversations

* Remove unnecessary TableExpr/ColumnExpr

* Use struct tags for both unique constraints on Conversation

* Make it clear how paging with GetDirectStatusIDsBatch should be used

* Let conversation paging skip conversations it can't render

* Use Bun NewDropTable

* Convert delete raw query to Bun

* Convert update raw query to Bun

* Convert latestConversationStatusesTempTable raw query partially to Bun

* Convert conversationStatusesTempTable raw query partially to Bun

* Rename field used to store result of MaxDirectStatusID

* Move advanced migrations to their own tiny processor

* Catch up util function name with main

* Remove json.… wrappers

* Remove redundant check

* Combine error checks

* Replace map with slice of structs

* Address processor/type converter comments

- Add context info for errors
- Extract some common processor code into shared methods
- Move conversation eligibility check ahead of populating conversation

* Add error context when dropping temp tables

1 files changed, 11 insertions, 2 deletions

diff --git a/internal/processing/workers/surfacetimeline.go b/internal/processing/workers/surfacetimeline.go
index 41d7f6f2a..8ac8293ed 100644
--- a/internal/processing/workers/surfacetimeline.go
+++ b/internal/processing/workers/surfacetimeline.go
@@ -36,8 +36,8 @@ import (
 // and LIST timelines of accounts that follow the status author.
 //
 // It will also handle notifications for any mentions attached to
-// the account, and notifications for any local accounts that want
-// to know when this account posts.
+// the account, notifications for any local accounts that want
+// to know when this account posts, and conversations containing the status.
 func (s *Surface) timelineAndNotifyStatus(ctx context.Context, status *gtsmodel.Status) error {
 	// Ensure status fully populated; including account, mentions, etc.
 	if err := s.State.DB.PopulateStatus(ctx, status); err != nil {
@@ -73,6 +73,15 @@ func (s *Surface) timelineAndNotifyStatus(ctx context.Context, status *gtsmodel.
 		return gtserror.Newf("error notifying status mentions for status %s: %w", status.ID, err)
 	}
 
+	// Update any conversations containing this status, and send conversation notifications.
+	notifications, err := s.Conversations.UpdateConversationsForStatus(ctx, status)
+	if err != nil {
+		return gtserror.Newf("error updating conversations for status %s: %w", status.ID, err)
+	}
+	for _, notification := range notifications {
+		s.Stream.Conversation(ctx, notification.AccountID, notification.Conversation)
+	}
+
 	return nil
 }