Add is: parameter to the length validator

[Dakad]

This PR is to complement the length validator introduced in #2437.
It adds an exact: param to verify that the given param is exactly equal to a limit.

[dblock]

I like it. I think we may want to call this equals or even value to match other value parameters, wdyt?

[Dakad]

I like it. I think we may want to call this equals or even value to match other value parameters, wdyt?

For me, equals is better than value. What about equal without s?
Either way, I'm not too concerned about the naming 😄

[dblock]

Is equal like min and max? I think value is more like those, but I am flexible :) What does @dhruvCW who introduced this parameter, or @ericproulx think?

Stepping back, I think length should simply accept a value, so

 requires :code, type: String, length: 2

[Dakad]

Is equal like min and max? I think value is more like those, but I am flexible :)

Not sure I understand the 1st question.

If I can add my two cents, I would prefer to split into distinct length validators.
In my company, before the length validator was introduced, we currently have 3 distinct validators for the length, exact_length: , min_length: and max_length: . They have _length suffix because we don't want to confuse the with max or min parameter value and to have use validator to such as max_element:, ....

[dblock]

I think it's pretty easy to grok length: { min: X, max: Y } and length: 2, would love to hear other (strong) opinions.

Note that we did add length in #2437, and it was released, so switching to 3 validators would be a breaking change, and we should be convinced that it's somehow a lot better if we want to deprecate one and introduce the other.

[ericproulx]

Is equal like min and max? I think value is more like those, but I am flexible :) What does @dhruvCW who introduced this parameter, or @ericproulx think?

Stepping back, I think length should simply accept a value, so

 requires :code, type: String, length: 2

Rails's Length Validator uses is for exact length. Ain't shocking for me reading

requires :code, type: String, length: { is: 2 }

Suggestion: having in would be great too to define a range

requires :code, type: String, length: { in: 5..10 }

[dblock]

I'd be good with is, but Grape also has value elsewhere (not in a validator), so that's why I suggested that.

Suggestion: having in would be great too to define a range

For large ranges doesn't that explode them causing potentially other problems? But otherwise we could support it along with min and max.

I think @Dakad is looking for some consensus. What's your strong opinion @ericproulx?

[ericproulx]

I'd be good with is, but Grape also has value elsewhere (not in a validator), so that's why I suggested that.

Suggestion: having in would be great too to define a range

For large ranges doesn't that explode them causing potentially other problems? But otherwise we could support it along with min and max.

I think @Dakad is looking for some consensus. What's your strong opinion @ericproulx?

value is used in except_value_validator and wording makes sense since the name of the validator is except_value. For length, I would stick to length { is: 1 }.

About the range, Ruby will manage its within a Range object. I'm not worried about large ranges since endless ranges are managed since Ruby 2.6.

[Dakad]

Change done!

[dblock]

To be or not to be, that is the question. I'm good with this, thanks for hanging in here with us @Dakad. Maybe you want to take the range idea on :)