`EnsureInt()` as parameter constraint sometimes too unspecific

[mih]

Example: --recursion-limit uses EnsureInt, but likely would not be happy to receive a -234 as a value.

Given the ambiguity, a GUI input widget can also not infer an adequate input range.

[yarikoptic]

likely we want to add optional min and max attributes

[mih]

Well OP was correct, but also not well informed. The desired constraint is easily possible with built-in tools:

(EnsureInt() & EnsureRange(min=0)) | EnsureNone()