IFormFile model binder suppressing validation for any non-null result.

[WillRay]

The FormFileModelBinder suppresses any further validation if a value is found. This can result in some confusion (example) because any validation attributes attached to a property that is an IFormFile or collection of IFormFiles will not be invoked if any files actually exist.

Is this suppression necessary?

[danroth27]

@rynowak Looks the suppression was deliberate. Do you remember why the suppression was added? Would it make sense to support [Required] on an IFormFile property?

[rynowak]

Yeah, this was deliberate, and I think we just got this wrong. What we should be doing is setting ModelMetadata.ValidateChildren to false for this type, and but not suppressing validation of the node.

[Eilon]

Ok let's fix in RTM then.

[rynowak]

e1abb47