如果我们只调用一次函数，我们应该使用'use'吗？

Question

Is it bad to use the keyword use even though we only call a function once? E.g. I have my own typo3 extension, and I am accessing a typo3 core function in my controller, but only once.

$message = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance('TYPO3\\CMS\\Core\\Mail\\MailMessage');

I could also make use of use:

use \TYPO3\CMS\Core\Utility\GeneralUtility;
...
$message = GeneralUtility::makeInstance('TYPO3\\CMS\\Core\\Mail\\MailMessage');

In my opinion the second variant is much cleaner, but are there any performance issues if I make use of use only for one call?

Answer 1

In theory, there should be no performance hit. You're calling a function (and thus an autoloader) either way (which is where any performance hit will be).

To explain why, your use statement is simply an alias. Your autoloader will do the same work either way. And it will likely be opcode cached, so any performance hit (we're talking milliseconds here, if that) will only be on the first run.