[7.x] Cast primary key to string when $keyType is string

[stevethomas]

Problem

Given a model with a string primary key:

 public $incrementing = false;

 protected $keyType = 'string';

and then running this on the model:

PaymentProvider::find(0);

I expect a null result, but in fact I get the first row in the table.

Looking at the underlying query, sure enough it runs select * from payment_providers where id = 0; MySQL seems to have a quirk where it will return all rows when comparing a string to a 0 integer.

MySQL aside, I think Laravel should take care of casting the primary key according to $keyType to prevent unexpected results.

Solution

This PR checks the primary key type, and casts to a string when required in whereKey() and whereNotKey().

Caveats

PaymentProvider::find([0]);

This query will return a collection of all rows in the table. I wasn't sure how to deal with an array of IDs, so I dealt with the singular lookup only.

[tobiasthaden]

I'm not sure if casting the attribute is the best solution. You specified the $keyType should be a string but you provide an integer. So the framework should may throw an InvalidArgumentException.

[driesvints]

@stevethomas FYI: this broke passing null as input: #34029

This should also have been sent to 6.x LTS (see our contribution guide). I've ported this to 6.x with an additional fix for the bug which will also make its way to 7.x: #34031

[stevethomas]

Noted @driesvints, i'll be sure to PR to both branches in the future.

[driesvints]

@stevethomas you don't need to PR to both. We merge 6.x into 7.x and 7.x into master regularly.