Clarify int converter in DEP 201

[adamchainz]

I think this should not be 'non-negative' in order to match Python, Flask, and even the example converter that follows in the DEP a few paragraphs later.

[adamchainz]

@sjoerdjob @tomchristie

[sjoerdjob]

In the discussions it has been made clear that int should take positive (or non-negative) input, not arbitrary integers.

This because negative values would most likely be errors, instead of intentional.

(Paraphrasing what Aymeric said in one of the relevant threads which I can't find right now)

[adamchainz]

Ok fair enough, couldn't see any discussion on this either and was confused by the example.

Looked a bit further, Flask is using werkzeug's converters, for which the int one does in fact not accept negative values: https://github.com/pallets/werkzeug/blob/02f5784afce7779450f8f6be7c083dab5670ca68/werkzeug/routing.py#L1032 .

Still, I'd like to suggest the name integer to make it clear this isn't just calling Python's int() (which does accept negative values).

[timgraham]

This is implemented as currently documented.