Rethink max_exclusive, convert to max_inclusive?

[samuelcolvin]

If we have MaxLen, and (in pydantic at least) that can be set via a max_length argument.

I really think this should mean "maximum inclusive", not "maximum exclusive" as currently documented.

This matches (IMHO) much better people's assumption about what MaxLen(5) or max_length=5 or Len(0, 5) means:

"The airbnb allows maximum 5 guests", you would assume 5 guests were allowed, not just 4

If for the sake of correctness, that involves either:

• treating slices differently
• or, removing the recommendation on allowing slices

That's sad, but I think a price worth paying.

At the end of the day max_length=5 meaning any length up to 4, won't fly in pydantic.

[samuelcolvin]

My personal preference would be to treat slices e.g. 2:10 as Len(min_inclusive=2, max_inclusive=10).

But I can already hear the rumbling of disagreement as I write that.

[adriangb]

max_length=5 meaning any length up to 4, won't fly

Yeah that is confusing to say the least!

either:

• treating slices differently
• or, removing the recommendation on allowing slices

My personal preference would be to remove slices.

[Zac-HD]

Yeah, this is a compelling argument. Let's remove slices and make both inclusive, and consider changing the name - min/max_len would match the other names, or min/max_size would match Hypothesis.

[samuelcolvin]

Agreed, I'd prefer min_length / max_length to match MinLen / MaxLen / Len, but easy on that.

[samuelcolvin]

I'll submit a PR once #21 is merged.