[0.12.83] remembering and forgetting returned values feature doesn't take side effects into account

[jacekkarczmarczyk]

Bug report

This can be quite tricky. Some functions may have side effects so that remembering return value doesn't make sense if next actions mutates the state

Code snippet that reproduces the problem

if (file_exists('foo')) {
	unlink('foo');
	if (file_exists('foo')) {
		echo "File still exists although it was deleted";
	}
}

https://phpstan.org/r/61c5bd5b-dc64-4562-aa3c-49cf7de51992

Expected output

No error

[dktapps]

It doesn't make sense in this case anyway, because file_exists() depends on filesystem state (e.g. if the file was deleted, the result might change). Because it depends on state, file_exists() should be considered to have side effects itself.

[ondrejmirtes]

PHPStan currently requires you to call clearstatcache between the calls: https://phpstan.org/r/8a78a20f-7d2c-4863-812d-9347933aa159

What I haven't noticed is this sentence in PHP manual:

However unlink() clears the cache automatically.

So I'll fix this scenario.

[ondrejmirtes]

Fixed: phpstan/phpstan-src@63d0670

[github-actions]

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