nonEmpty validation doesn't work on Int values

[amitaibu]

I have a non nullable Int field, however I cannot add nonEmpty field on it as there's the error Could not deduce (IsEmpty Int) arising from a use of nonEmpty'`

[mpscholten]

If the int field is empty, the int field parser will fail to parse the empty string and produce an error like this:

So i think no nonEmpty is needed in this case. Or do i miss something?

[amitaibu]

I have this an in exiting Repo, where the error of validation of the form is that of a sub-record.
Here's the code - https://github.com/amitaibu/ihp-bid/blob/a02ee2860811baf35b591bebf4c44d1e6274be99/Web/Controller/Items.hs#L71

Steps to reproduce

1. Checkout https://github.com/amitaibu/ihp-bid
2. Visit http://localhost:8000/NewItem
3. Add title
4. Submit form

Current behavior

[amitaibu]

I was able to find the line that is causing the 'min' is invalid CallStack... and that's getValidationFailure #min bidStep

Still not sure why, I'll try to dig.

[amitaibu]

Sorry, it's not that. I'll have to come back to it with fresh eyes, but something is weird 😸

[amitaibu]

Seems the error is coming from

ihp/IHP/Controller/Param.hs

Lines 113 to 123 in 6f5f3f9

	paramList :: forall valueType. (?context :: ControllerContext, DeepSeq.NFData valueType, ParamReader valueType) => ByteString -> [valueType]
	paramList name =
	allParams
	|> filter (\(paramName, paramValue) -> paramName == name)
	|> mapMaybe (\(paramName, paramValue) -> paramValue)
	|> map (readParameter @valueType)
	|> map (Either.fromRight (error (paramParserErrorMessage name)))
	|> DeepSeq.force
	{-# INLINABLE paramList #-}
	paramParserErrorMessage name = "param: Parameter '" <> cs name <> "' is invalid"

If the value is empty, it throws the error because it gets (min, "")

[amitaibu]

Closing in favor of #1130