计算不可数对象PHP 7.2

Question

I have been using PHP 5.4 until now in one of my old projects.

Recently I have decided to upgrade to PHP 7.2

I have around 800 files in my project and old developer team used count() hundreds of time in the project.

In PHP 5.4 even if the variable was not countable it worked as expected but in PHP 7.2 it throws an error.

I could go into each file and change the function but that could take a lot of time and the risk of not changing a couple of function here and there.

Can I extend count() function and write code to make it work as it used to in PHP 5.4 ?

Is there any other solution to this problem?

I am replacing all if conditions with count($var) functions to is_array($var) && count($var) for now.

Thank you

Answer 1

In other languages like Python you can use decorators to intercept an existing method without modifying the original method.

However PHP does not support decorators so you will need to manually change every location of that call.

Answer 2

The difference between php 5.4 and php 7+ on that aspect is not that count changed it's behavior, is that php now turned errors into catchable exceptions. Your code was failing silently on production with error_repoting turned off. That is extremely dangerous for the business, as the consistency of your app is unreliable, you should change that asap.

Having that said. Since all errors cannot be turned off anymore by setting your error_reporting to 0 (thats because now they are exceptions rather than errors, and that's really nice, php is no more a super unreliable language). You have to catch those exeptions, which are ErrorException.

Go to the index file of your application and add a try-catch block and swipe the dirty down the carpet again.

try {
   //super buggy app bootstraping
} catch (ErrorException $ex) {
    error_log($ex);
}

Well, i'd rather fix the counts anyway, they are toxic.

Note: is_array($var) && count($var) is not a goo idea, since arrays is not the only countable thing on php, ((is_array($var) || $var instanceof countable) && count($var)) would be a better, but not perfect solution. Also note a bug in php on any version - count(false) - returns 1

Answer 3

You can use runkit to overload the count() function with your own implementation:

// to override internal functions, this system INI value needs truthy
assert((bool)ini_get('runkit.internal_override'));

// now you can define your own implementation
runkit_function_redefine('count', function ($var) {
    return ((is_array($var) || $var instanceof \Countable) ? count($var) : 0);
});

However, please, consider using this only as a temporary stop gap to ease the pain of 5.4 to 7.2. Because this method is opaque, it'll become a maintenance liability at some point, a liability you probably don't want to linger.

Additionally, note that your conversion of is_array($v) && count($v) does not handle all countable things: ie, \\Generator and \\Traversable . The runkit override example above does handle them, though.

Answer 4

Fix your code rather, and learn to type . Make sure your count method returns something countable