Query parameter arrays don't parse correctly

[tasn]

Bug Report

Version

├── axum v0.4.4
│ ├── axum-core v0.1.1

Platform

Linux p15s 5.16.2-arch1-1 #1 SMP PREEMPT Thu, 20 Jan 2022 16:18:29 +0000 x86_64 GNU/Linux

Description

If you look at https://swagger.io/docs/specification/serialization/#query you'll see that the standard OpenAPI setting for query parameters is explode=true. What does that mean? It means that parameters are passed like this:

http://example.com?arr=item1&arr=item2

Axum however treats queries as a map and doesn't correctly parse these into an array. Instead it just uses the last one.

Expected:

arr: ["item1", "item2"]

Actual:

arr: "item2"

[davidpdrsn]

See #504

[tasn]

Sorry, and thanks!

[huntc]

As this turned up first on Google for me, https://github.com/tokio-rs/axum/tree/main/axum-extra's Query declaration supports multi-valued query params.