Bug #72084 [Opn->Nab]: is_callable returns true for array with class and non static method

Edit report at https://bugs.php.net/bug.php?id=72084&edit=1 ID: 72084 Updated by: requinix@php.net Reported by: heah at heahprod dot com Summary: is_callable returns true for array with class and non static method -Status: Open +Status: Not a bug Type: Bug -Package: Reproducible crash +Package: Scripting Engine problem Operating System: os X 10.11.4 PHP Version: 5.6.20 Block user comment: N Private report: N New Comment: To be honest I'm a little confused by your description. So I'll start from the beginning. https://3v4l.org/2P3dd The four class/object + instance/static method combinations are callable in the sense that you can successfully use call_user_func() on them. For the two odd cases, 1. For now, calling an instance method from a static context is allowed for compatibility with old PHP scripts and methods that were written without the "static" keyword. Perhaps PHP 4-era code and practices. However doing so could easily be the source of problems so PHP will raise a strict/deprecated notice when that happens. 2. Calling a static method from an instance context is a bit odd but there isn't really any technical reason why that should not be allowed. So PHP allows it silently. And that fatal error? Even though PHP allowed the instance-method-from-static-context call, the method did something PHP couldn't recover from: try to use $this. Since it's a static call there is no instance to bind to $this and PHP has no choice but to fatal. Does that make sense? Previous Comments: ------------------------------------------------------------------------ [2016-04-23 03:53:18] heah at heahprod dot com Description: ------------ Hi, documentation says that valid callables might be string name of functions, closure, or: "A method of an instantiated object is passed as an array containing an object at index 0 and the method name at index 1. Accessing protected and private methods from within a class is allowed. Static class methods can also be passed without instantiating an object of that class by passing the class name instead of an object at index 0. As of PHP 5.2.3, it is also possible to pass 'ClassName::methodName'." ref http://php.net/manual/en/language.types.callable.php However "is_callable" does not behave as I would expect when passing an array with a class and a non static method, true is returned instead of false. Is this an expected behavior? Shouldn't we rely on "is_callable" before calling "call_user_func"? If not please update or let me know if I should open another issue for: http://php.net/manual/en/function.is-callable.php since it currently says: "Verify that the contents of a variable can be called as a function. This can check that a simple variable contains the name of a valid function, or that an array contains a properly encoded object and function name." If we change the test script I provide to "echo" a regular string like "object call" instead of using an object property, the string is printed after the warning triggered by "is_callable", so "call_user_func" is actually called. Since I'm just a php beginner and don't know anything about the internal, I don't know if the error comes with "is_callable" because "call_user_func" is actually callable or if it comes from "call_user_func" because "is_callable" returns true. But my guess is that "call_user_func" should test internally if the array is callable (second case), and throw an invalid argument exception instead. The a user like me should be able to use "is_callable" before using it and getting the invalid argument exception. However the current fatal error got from the provided test script looks really wrong to me. Note that it happens in my local environment but not on my server holding the script online. Thank you for your time reading this and for working on PHP, it is an awesome open-source project! (sorry for any mistake, this is my first issue report and I'm not a native speaker). Test script: --------------- http://heahprod.com/php/bug-is_callable.php Expected result: ---------------- static call static call object call object message Actual result: -------------- static call Strict Standards: call_user_func() expects parameter 1 to be a valid callback, non-static method SomeClass::someObjectMethod() should not be called statically in /test.php on line 39 object call Strict Standards: call_user_func() expects parameter 1 to be a valid callback, non-static method SomeClass::getMessage() should not be called statically in /test.php on line 45 Fatal error: Using $this when not in object context in /test.php on line 19 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=72084&edit=1