I ran into the same issue and I've been working on it a bit. The Typify https://github.com/oxidecomputer/typify?tab=readme-ov-file#arrays crate mentions that a type: array in the JSON schema can be parsed as 3 different types:

• Vec
• HashSet
• (T, T, ...) (Depending on size)

Which are all doable, but need their own code paths.

Next issue is that it is determining the capacity of the Vec for the query to make based on the amount of params the function gets, however if we input an exploded version into the query vec this size will potentially be larger, or empty if the vec is empty. This is will not affect the functionality though, but it's a minor performance impact.

If we push a non-exploded version (1,2,3) the size is not an issue.

Progenitor also does not seem to grab the explode information from openapiv3::Parameter::Query, but it is available and can easily be added to the OperationParameter struct to be processed.

It looks to me like the implementation of the code fragment you linked is wrong for any kind of array type: Vec doesn't have a ToString implementation for any T.

But even there was a .to_string() impl for vectors, the way progenitor tries to do that (by pushing api_parameter_name=<value.to_string()> to the query string) makes it impossible to pass even the RFC6570/3.2.8 kind of api parameter in a vector (where it should encode api_parameter_name=foo&api_parameter_name=bar): You could try to make a newtype that has a ToString impl, which could create a query string fragment, interspersing the values with &api_parameter_name=... which then would get escaped by the reqwest query builder.

I think this might need a new trait for converting to/modifying a query string? Maybe something like this sketch (not tested, of course!):

trait AddToQuery {
  fn add_to_query(self, query: &mut Vec<(String, String)>, name: &str);
}

impl<T: ToString> AddToQuery for T {
  fn add_to_query(self, query: &mut Vec<(String, String)>, name: &str) {
    query.push(name, self.to_string());
  }
}

impl<T: ToString, I: IntoIterator<Item=T>> AddToQuery for T {
  fn add_to_query(self, query: &mut Vec<(String, String)>, name: &str) {
    for item in self.into_iter() {
      query.push(name, item.to_string());
    }
  }
}

...or something.

Any fix or workaround for this yet?