unlink(System_Development.log.10): No such file

Using Neos & Flow
2

This seems to be an issue in the log rotation (as the entry with the suffix .10 is attempted to be removed)

During log rotation we attempt to use a lock via file_exists but its not an atomic operation how we use it flow-development-collection/Neos.Flow.Log/Classes/Backend/FileBackend.php at 54cea0a2cafb9ee1475ae2fdbc1fd3a1830ddc86 · neos/flow-development-collection · GitHub
file_exists could be true for two processes at the same time in a race condition and both processes would touch the lock file.

Instead we need to use an atomic locking

$lockResource = fopen($this->logFileUrl . '.lock', 'w+');

$exclusiveNonBlockingLockResult = flock($lockResource, LOCK_EX | LOCK_NB);
if ($exclusiveNonBlockingLockResult === false) {
   // someone else is on it
   return;
}

// do something only this process is supossed to do...

if (!flock($setupLockResource, LOCK_UN)) {
    throw new \RuntimeException('failed to release lock');
}

ill prepare a PR for testing