[8.x] Respect custom route key with explicit route model binding

[erikgaal]

Hi there! 🚀

You can use explicit route model binding in a situation where implicit binding might not work. Implicit binding allows you to customize the binding field for each route.

Route::get('/post/{post:slug}', fn (Post $post) => $post->content);
Route::get('/posts-by-id/{post}', fn (Post $post) => $post->content);

Unfortunately, this doesn't work when you're using explicit binding. It always uses the $model->getRouteKeyName().

Route::model('post', Post::class);

This PR makes sure that when explicitly binding models to route paramters, they respect any custom route fields being used.

Additionally, it passes the custom key to custom route binding.

Route::bind('post', function ($value, $route, $key) {
    // do something
});

[taylorotwell]

Does this contain any (even minor) breaking changes?

[GrahamCampbell]

Breaking in the sense that someone relying on the old behaviour (because they assumed "that's just how it works"), will have their app broken.

[erikgaal]

Does this contain any (even minor) breaking changes?

I left the order of parameters unchanged so it doesn't break your current routes. But like @GrahamCampbell said, if you rely on the broken behavior, then this will be a breaking change.

[taylorotwell]

Broken: #36443

Reverting.