PSR1 recommends that each class should be in its own file to aid autoloaders.
Having each class in a dedicated file usually plays nice with PSR autoloaders
and is therefore a well established practice. If you use other autoloaders, you
might not want to follow this rule.
It seems like $node->parent can be null; however, find() does not accept null, maybe add an additional type check?
Unless you are absolutely sure that the expression can never be null because of
other conditions, we strongly recommend to add an additional type check to your
code:
/** @return stdClass|null */functionmayReturnNull(){}functiondoesNotAcceptNull(stdClass$x){}// With potential error.functionwithoutCheck(){$x=mayReturnNull();doesNotAcceptNull($x);// Potential error here.}// Safe - Alternative 1functionwithCheck1(){$x=mayReturnNull();if(!$xinstanceofstdClass){thrownew\LogicException('$x must be defined.');}doesNotAcceptNull($x);}// Safe - Alternative 2functionwithCheck2(){$x=mayReturnNull();if($xinstanceofstdClass){doesNotAcceptNull($x);}}
Having each class in a dedicated file usually plays nice with PSR autoloaders and is therefore a well established practice. If you use other autoloaders, you might not want to follow this rule.