[5.4] Adds is_null check to Eloquent Builder callScope

[alihamze]

This fixes #19380 by adding an is_null check before calling count() and defaulting to 0 if it is null.

[brickgale]

is this fix possible to be port over lower versions of laravel? *currently encountering this error on version 5.2.* in latest homestead environment. confirmed it fix, changed it manually on vendor file.

[omeha2]

Maybe better just change
public $wheres;
to
public $wheres = [];
in \Database\Query\Builder?

[peyobr]

It would be fixed in L5.2.* as well?

Yesterday upgraded to PHP7.2 and now production service is broken.

Please let me know. Thank you.

[omeha2]

Yes thats only one problem which i had after upgrading to 7.2

[devcircus]

How far back to go? I wouldn't expect unsupported versions of a framework to continue working on each iteration of PHP. However, if it's a simple fix, maybe a PR would be accepted.

[aleemb]

@taylorotwell Can we commit this to 5.2 and 5.3 branches also? It will open those up to PHP 7.2 as well.

[alihamze]

@aleemb They already said 5.2 is closed #22927 so doubt it'll get ported back. 5.3 should already be fixed #22567