[4.2] Don't allow relations to be accessed via snake case

[anlutro]

This is just a weird inconsistency that will catch you off guard. If you eager load a multi-word relationship (using camel case function names of course) but access it via snake case, it will bypass the eager loading.

The alternative is to move the converting of $key to camel case before checking if the key exists in the already loaded relations.

[JoostK]

I remember how this has been such a pain in the early days :(

[taylorotwell]

Not going to do this. Just define functions as camelCase and access them camelCase.

[lazychaser]

@taylorotwell why then camel_case attribute here? It allows to access same attribute two ways which obfuscates a little.

[Xethron]

Agreed! I quite like the snake_case, however, I've spend the past few hours figuring out why my view generates 400 queries, and if it wasn't for @anlutro, I never would've found it. If I got an error this would've saved me a LOT of time.

So, ether set eager loading to work with snake_case, or drop snake_case altogether! But having a semi working snake_case implementation will only cause problems.