Required validator ignores 0 assuming the field is not provided

[hamidr]

Package version: v10

Issue:

Hey, folks :)
Required validator ignores 0 assuming the field is not provided.
This seems to be a default value issue.
I guess it can't be fixed?

Code sample, to showcase or reproduce:

import  "github.com/go-playground/validator/v10"

type Filter struct {
	Skip    int           `json:"skip,integer" form:"skip" validate:"required"`
}

f := Filter { Skip: 0 }
if err := validator.New().Struct(query); err != nil {
    print("No 0 is not an integer")
} else { //it should be.
    print("https://en.wikipedia.org/wiki/Integer")
}

[hamidr]

Haha... This actually is a "required" problem because it seems that 0 means the value is not provided.

[atsikham]

The same for empty string. Are there any examples with the case when string is required but might be empty?

[MiraiTunga]

you can use gt as a work around e.g

type Filter struct {
	Skip    int    `json:"skip,integer" form:"skip" validate:"gt=-1"`
}

[deankarn]

Hello @hamidr

sorry I’ve let this issue linger been rather busy lately.

so this has been asked and covered many times in separate issue but to reiterate.

If you read the “required” documentation carefully you will note it states it validates that the value isn’t it’s types default. So “required” is working as intended.

Go does not have a notion of uninitialized variables and so the default is always the types default.

Go also does not have a nice way to denote an optional variable like rusts “Option” either but there are 2 options in Go:

1. Make the field a pointer and then the default value will be nil and if the value is present it won’t be nil anymore.
2. Create a custom type similar to the sql.NullString, sql.Null* custom types and then register a custom type function with the validator library.

I hope this clarifies things :)