Patterns for structs with single unnamed field

[johnperry-math]

For the following struct,

struct Thing(T);

I would like to restrict T using some of the options available for structs with named fields, such as restricting a String to a pattern, or a numerical type to a minimum and maximum. Is there a way to specify this using the #[schema(...)] macro?

[juhaku]

In theory it could be possible for primitive types like str, String, i32 etc. But not for $ref types (Types that are a reference to another ToSchema type). Thus its is not implemented and supported at the moment.

Thing is that the validation rules are to be added on schema properties yet struct Thing(T) is not a struct with fields but will render a schema for T within the Thing struct. When T is a String it will render the schema for the String and validation rules are not exactly placed on a type but alongside of a type on a property. But unnamed field structs do not have properties.

This is something that could be explored in future but at the moment the priority for the support is not very high.

[johnperry-math]

In theory it could be possible for primitive types like str, String, i32 etc.

FWIW that happens to be my use case, but I can understand the priority being low.

If I can follow up, though: in point of fact I am annotating it this way:

#[derive(ToSchema)]
#[schema(example = "mymommatoldme", value_type = String)]
struct Thing(T);
// a function exists to convert String to Thing(T)

Would some workaround like this allow me to define a pattern? I thought about defining a new type, but I couldn't work out anything specific, because patterns apply only to fields.

[ValentinColin]

A lot of people use newtypes on primitives. Moreover, since the fields pattern, min, max, ... exist on named structures, wouldn't it be nice to add this feature to unnamed structures?

[juhaku]

Such functionality could be evaluated in future.

[juhaku]

Duplicate #1150