copy() target is blank in PHP 8.2.0-rc3

[pesselbach]

Description

The following code:

<?php
copy("test.txt", "testcopy.txt");

Resulted in this output:
testcopy.txt is an empty 0 bytes file.

But I expected this output instead:
testcopy.txt is a copy of test.txt

The following workaround is working:

<?php
file_put_contents("testcopy.txt", file_get_contents("test.txt"));

This problem exists at least since PHP 8.2.0-rc1. Production versions such as PHP 8.1.11 are working as expected. I am using Debian 10 with the packages provided by https://deb.sury.org running in a VirtualBox machine.

PHP Version

PHP 8.2.0-rc3

Operating System

Debian 10

[devnexen]

I built the same environment but was unable to reproduce the issue, always successful copies. Is it possible to get a bit more context or a minimum reproducer ?

[pesselbach]

I did further testing. This only happens if the target directory is in a VirtualBox shared folder.

[devnexen]

Thanks. It might have to do with the copy optimisation introduced couple of months ago and we re running a kernel version pre-5.3. Indeed, when I boot with the other buster kernel image 5.10, the copy seems to work.

[devnexen]

@pesselbach you can try the aforementioned PR branch, the copy worked again on the base 4.19 kernel image with this change.

[bukka]

@devnexen Added few comments on one of the commits - not sure if it's visible. Maybe just do a PR. It seems reasonable to me to do this check if it doesn't work well before 5.3 kernel.

[devnexen]

PR is there ;-) but yes I did see your comments thx