When null is passed as the parameter to get_class() inside a class context, the behaviour of the function can be highly surprising,
class Foo { function bar($repository) { $result = $repository->find(100); echo get_class($result); } }
If $result contains a valid object returned from the repository, the output will be of the class name of the type of $result.
If $result contains null, the output will be of the class context where get_class() was called from, in this case “Foo”.
This feature violates the Principle of least astonishment: “if a necessary feature has a high astonishment factor, it may be necessary to redesign the feature.”
Disallow null being passed to the function as a valid parameter. If get_class() is called with null as the parameter, a warning will be emitted:
Warning: get_class() expects parameter 1 to be object, null given in %s on line %d
I.e. the valid ways to call the function will be:
Those two options will continue to have the same behaviour they currently have.
Most people won't see a BC break, as for the majority of people, passing null to this function is not a desired behaviour.
For people who do deliberately pass null to the function they will need to refactor their code from:
$x = get_class($some_value_that_may_be_null);
to:
if ($some_value_that_may_be_null === null) { $x = get_class(); } else { $x = get_class($some_value_that_may_be_null); }
7.2
Should the get_class() function be changed to disallow null being passed as a parameter? As it is not a language or syntax change, the vote will pass if 50%+1 vote yes.
Voting ended on the 8th October 2016 9pm UTC
When this topic was discussed before, it came as a surprise to some people that PHP can tell the difference between passing null and having a default value be null. This is perfectly possible in both internal code, as well as userland code:
function get_class($item = null) { if (func_num_args() == 0) { return get_current_scope_name(); } if ($item === null) { trigger_error("get_class passed null, which is not an object."); } if (is_object($item) == false) { trigger_error("value is not an object"); return false; } return gettype($item); }
After the project is implemented, this section should contain