Min() is not working for 0 for int field

[arafatazam]

I have an int field which needs to be at least 1. I am using validation.Min(1) for validation but, the validation is letting 0 (zero) to pass.

[qiangxue]

0 is considered as an empty value. You should add a Required rule to make sure the value is not empty.

[JensErat]

I'm not sure whether this works out. Consider I have an integer and I want to validate it is inside a given slice, like []int{0,23,42}. Also applying Required doesn't help either, because then I would exclude the value entirely.

How to implement this validation if the zero integer is to be considered a non-empty value? This is surely a good behavior for some cases, but blocking other valid use cases.

[qiangxue]

For your example, you can use an In(23, 42) rule. This will let 0, 23, or 42 pass the validation and nothing else.

[moskyb]

To add on to this: I'm using ozzo-validation to check a limit parameter being passed to my API. The limit determines how many results I should return to the user, and has type *int - it's okay for this parameter to be nil (in which case I can set it to a default value), but if it is explicitly passed by the user, then 0 isn't an acceptable input.

NotIn(0) doesn't work either, as NotIn does the same nil/zero check as Min. Perhaps a good solve to this would be an explicit check in NotIn that specifically denies zero values if they're the arg to NotIn - ie

validation.ValidateField(0, validation.NotIn(0))

Would return an error.