FileEvaluator does not support race condition

[koschos]

RulerZ\Compiler\FileEvaluator is going to fail on race condition (concurrent writes). Consider the following situation. https://github.com/K-Phoen/rulerz/blob/master/src/Compiler/FileEvaluator.php

Thread 1 is writing file content, but not finished yet (L25) Thread 2 is checking if the file exists (L24), gets true and requires the file (L28) while writing process is not finished (Thread 1), which leads to Fatal.

Possible solutions are:

• using of Symfony Filesystem which handles concurrent writes via temp files https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Filesystem/Filesystem.php#L677
• using LOCK_EX third parameter for file_put_contents (L25) http://php.net/manual/ru/function.file-put-contents.php

[K-Phoen]

Thanks for reporting the issue (and well done finding it!)

I wrote a fix (see the PR #100) which is released in the version 0.20.5