Honour history_visibility when backfilling (#990)

* Make backfill work for shared history visibility

* fetch missing state on backfill to remember snapshots correctly

* Fix gmsl to not mux in auth events into room state

* Whoops

* Linting

2 files changed, 13 insertions, 17 deletions

diff --git a/roomserver/storage/sqlite3/events_table.go b/roomserver/storage/sqlite3/events_table.go
index d881fa91..a63596ae 100644
--- a/roomserver/storage/sqlite3/events_table.go
+++ b/roomserver/storage/sqlite3/events_table.go
@@ -48,11 +48,6 @@ const insertEventSQL = `
 	  ON CONFLICT DO NOTHING;
 `
 
-const insertEventResultSQL = `
-	SELECT event_nid, state_snapshot_nid FROM roomserver_events
-		WHERE rowid = last_insert_rowid();
-`
-
 const selectEventSQL = "" +
 	"SELECT event_nid, state_snapshot_nid FROM roomserver_events WHERE event_id = $1"
 
@@ -102,7 +97,6 @@ const selectRoomNIDForEventNIDSQL = "" +
 type eventStatements struct {
 	db                                     *sql.DB
 	insertEventStmt                        *sql.Stmt
-	insertEventResultStmt                  *sql.Stmt
 	selectEventStmt                        *sql.Stmt
 	bulkSelectStateEventByIDStmt           *sql.Stmt
 	bulkSelectStateAtEventByIDStmt         *sql.Stmt
@@ -126,7 +120,6 @@ func (s *eventStatements) prepare(db *sql.DB) (err error) {
 
 	return statementList{
 		{&s.insertEventStmt, insertEventSQL},
-		{&s.insertEventResultStmt, insertEventResultSQL},
 		{&s.selectEventStmt, selectEventSQL},
 		{&s.bulkSelectStateEventByIDStmt, bulkSelectStateEventByIDSQL},
 		{&s.bulkSelectStateAtEventByIDStmt, bulkSelectStateAtEventByIDSQL},
@@ -152,19 +145,22 @@ func (s *eventStatements) insertEvent(
 	referenceSHA256 []byte,
 	authEventNIDs []types.EventNID,
 	depth int64,
-) (types.EventNID, types.StateSnapshotNID, error) {
-	var eventNID int64
-	var stateNID int64
-	var err error
+) (types.EventNID, error) {
+	// attempt to insert: the last_row_id is the event NID
 	insertStmt := common.TxStmt(txn, s.insertEventStmt)
-	resultStmt := common.TxStmt(txn, s.insertEventResultStmt)
-	if _, err = insertStmt.ExecContext(
+	result, err := insertStmt.ExecContext(
 		ctx, int64(roomNID), int64(eventTypeNID), int64(eventStateKeyNID),
 		eventID, referenceSHA256, eventNIDsAsArray(authEventNIDs), depth,
-	); err == nil {
-		err = resultStmt.QueryRowContext(ctx).Scan(&eventNID, &stateNID)
+	)
+	if err != nil {
+		return 0, err
 	}
-	return types.EventNID(eventNID), types.StateSnapshotNID(stateNID), err
+	modified, err := result.RowsAffected()
+	if modified == 0 && err == nil {
+		return 0, sql.ErrNoRows
+	}
+	eventNID, err := result.LastInsertId()
+	return types.EventNID(eventNID), err
 }
 
 func (s *eventStatements) selectEvent(
diff --git a/roomserver/storage/sqlite3/storage.go b/roomserver/storage/sqlite3/storage.go
index 5df9c4e0..b6e846df 100644
--- a/roomserver/storage/sqlite3/storage.go
+++ b/roomserver/storage/sqlite3/storage.go
@@ -124,7 +124,7 @@ func (d *Database) StoreEvent(
 			}
 		}
 
-		if eventNID, stateNID, err = d.statements.insertEvent(
+		if eventNID, err = d.statements.insertEvent(
 			ctx,
 			txn,
 			roomNID,