Can we enable the snapshot time to be in the future?

[PaulRBerg]

Hey @sablier-labs/solidity, I've a question about #351.

Can we enable the snapshot time to be in the future, not just in the past?

This would make it possible to schedule payrolls in advance.

[smol-ninja]

I'd be careful to call it snapshot time. We have an invariant: $\text{snapshot time} \le \text{block time}$.

However, this feature can be implemented by introducing a new storage called startTime. So that until start time, the rps will be 0 and no streaming will be taking place. The ongoing debt calculation will also take into account whether block time is greater than start time or not.

[PaulRBerg]

Alright.

Why was that invariant there in the first place?

[smol-ninja]

Because in the current version, snapshots have a meaning which is to update snapshot debt and the associated time is called snapshot time.

So the invariant made sense. To allow streams to begin in future, the modification would be to allow setting snapshot time as a future timestamp but only while creating/resuming the stream.

[PaulRBerg]

Hmm this sounds a little tautological to me.

But anyway, I think we can safely remove the invariant and allow snapshots to be in the future (without ruining the semantics). A future snapshot makes logical sense.

[smol-ninja]

Sounds good. Lets make it a part of #351?

[PaulRBerg]

Done. I've updated the issue title and description.