* Improve `debug_handler` to use the correct span for specific bounds
This results in better localised error messages, as they now point
directly to the corresponding argument instead of to the macro itself.
* Improve some error messages behind a `nightly-error-messages` feature
flag
This uses the nightly only `rustc_on_unimplemented` attribute to improve
some error messages when users try to use invalid handler functions.
This should be seen as prove of concept, not as full solution for all
potential error cases.
The underlying feature is currently marked as permanently unstable, but
I'm working on getting this specific attribute (or an attribute with
different name, similar functionality) ready to work on a stable compiler.
* Apply suggestions from code review
Co-authored-by: Jonas Platte <jplatte+git@posteo.de>
* Enable the `nightly-error-messages` feature unconditionally for nightly compilers
* Use a nightly compiler to run the axum-marcos compile fail tests
* update to newer nightly
* Run axum-macros tests on nightly
* tweak compile error hints a bit
* more tweaks
* update test
Co-authored-by: Jonas Platte <jplatte+git@posteo.de>
Co-authored-by: David Pedersen <david.pdrsn@gmail.com>
* add `#[derive(FromRef)]`
* tests
* don't support skipping fields
probably wouldn't work at all since the whole state likely needs `Clone`
* UI tests
* changelog
* changelog link
* revert hello-world example, used for testing
* Re-export `#[derive(FromRef)]`
* Don't need to return `Result`
* use `collect` instead of quoting the iterator
* Mention it in axum's changelog
* Add a dedicated error message for state type inference issues
* Generate valid code even if state type can't be inferred
* Also error on state type inference for debug_handler
* Support `State` with `#[derive(FromRequest[Parts])]`
Fixes https://github.com/tokio-rs/axum/issues/1314
This makes it possible to extract things via `State` in
`#[derive(FromRequet)]`:
```rust
struct Foo {
state: State<AppState>,
}
```
The state can also be inferred in a lot of cases so you only need to
write:
```rust
struct Foo {
// since we're using `State<AppState>` we know the state has to be
// `AppState`
state: State<AppState>,
}
```
Same for
```rust
struct Foo {
#[from_request(via(State))]
state: AppState,
}
```
And
```rust
struct AppState {}
```
I think I've covered all the edge cases but there are (unsurprisingly) a
few.
* make sure things can be combined with other extractors
* main functions in ui tests don't need to be async
* Add test for multiple identicaly state types
* Add failing test for multiple states
