newQueue closes the shared *sql.DB on initTable failure, breaking all other queues

[fahimfaisaal]

Summary

newQueue closes the shared database connection when initTable fails, tearing down every other queue created from the same manager.

Root cause

queue.go:34-37:

if err := q.initTable(); err != nil {
    db.Close()          // <-- db is shared across all queues
    return nil, fmt.Errorf("failed to initialize table: %w", err)
}

The *sql.DB is owned by the queues manager (queues.go) and shared by every Queue/PriorityQueue. A single failed NewQueue/NewPriorityQueue closes the connection for all of them.

Impact

Medium. One bad table name or transient error during NewQueue silently breaks unrelated, already-working queues on the same manager. The manager's own Close() is the only thing that should close the DB.

Possible fix

Remove the db.Close() call; let the manager own the connection lifecycle:

if err := q.initTable(); err != nil {
    return nil, fmt.Errorf("failed to initialize table: %w", err)
}

The same shared-DB assumption should be double-checked in newPriorityQueue's error paths (priority_queue.go:17-33), which correctly do not close the DB today.