Function build_request_url 

pub fn build_request_url(
    base_url: &str,
    base_path: &str,
    method_binding: &HttpMethodBindingIr,
    fields: &Value,
    query: Option<&str>,
) -> Result<String, TransportError>

Build a fully-qualified URL by substituting path parameters and appending a pre-encoded query string, returning TransportError on failure.

fields is expected to be a JSON object whose keys correspond to the field names referenced by method_binding.field_bindings. Missing path parameters yield TransportError::UrlBuild.

query is the already-encoded query string (no leading ?), produced by crate::query::to_query_string. It arrives pre-encoded rather than as structured data on purpose: the server decodes it with the same serde_html_form codec, and routing it through this function’s own serializer is what previously let the two ends disagree on Vec and nested shapes.

Errors

Returns TransportError::UrlBuild when a required path parameter is missing, null, or empty, or when a referenced field is not convertible to a string.