id summary reporter owner description type status priority milestone component version severity resolution keywords cc focuses 40156 Warning for invalid hook callback is not very useful Shelob9 "If you add a hook with an uncallable callback, an error like `Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'not_a_function' not found or invalid function name in` is shown. This is technically correct, but not useful. When I say useful, I don't think it is useful to the following user profiles: 1) Non-technical user seeing errors. A non-developer might no what a WordPress hook is, but not how it works internally. Therefore they are not likely to understand this error is related to a hook. They are not given good information, and might be missing a clue as to who to ask for support (plugin or theme developer, host, etc.) 2) New developer. A developer new to WordPress might not understand yet what a hook is or that a missing callback generates this type of error. A more clear error will help guide their googling for the error and/ or help them find the issue in the code. 3) Experienced WordPress developer. When I see this error, I assume there is a non-callabale hook callback. But `call_user_func()` has other uses so it might be misleading to me. I think it would be way more helpful if the error triggered was something like `Hook $hook_name could not call $callback` or `The callback function $hook, registered for $hook_name is not callabale` " enhancement new normal Awaiting Review Plugins 0.71 normal