Spell Lock/Knock vs trapped chest

[DHood64]

Imagine a chest, locked with hasp with combination lock and also trapped if opened.

is that one sucessfull knock spell to loot the chest? maybe 2? to open it without triggering the trap - or cant a successful knock spell actually "open" the chest to bypass the "trap trigger on chest open"?

[Shostak]

Knock, if successfully cast, unlocks a single mundane lock without triggering any trap, or removes one Lock spell. In your example, I would rule that the hasp is not a lock, since it is more like a latch than a lock. The padlock is the lock, and one Knock spell should be sufficient to unlock it.

[DHood64]

so if first knock opened the combination padlock, is then needed/can then a second successful knock spell be used to bypass the "trap on opening"?

[Shostak]

The successful Knock on the padlock also disarms the trap. No second one needed. However, if the Knock spell is not successfully cast, the trap is immediately actuated.

[Anthony]

Knock targets a locking mechanism, if a chest has multiple locking mechanisms you need multiple knock spells. The trap is not connected to the lock, it's connected to opening the chest, so it's a separate locking mechanism and needs to be targeted separately. Unless the trap is designed to be disarmed when you turn the key in the lock.

[Shostak]

Knock can also open a door, not just unlock it, and do so without triggering a trap.