strtok is never false when called with both the string and the token

[aszenz]

Just want to confirm this is correct, before creating a pr:

So strtok returns false only it reaches the end of the string and there are no more tokens to extract like

$a = "hi this is good";
strtok($a, " "); // returns "hi"
strtok(" "); // returns "this"
strtok(" ")  ; // return "is"
strtok(" ")  ; // return "good"
strtok(" ")  ; // now it returns false after reaching the end of the string

But phpstan considers strtok($a, " ") to also return false|string even though its only when called without first argument that it can return false. Is there a way to model this function correctly with phpstan's types?

https://phpstan.org/r/abe8c204-911c-477e-bceb-8854d19ce4dc

[canvural]

If $a is an empty string it can also return false. But I guess this can be checked by PHPStan.

[aszenz]

@canvural

Thanks for the info, i guess that explains the false return type.

Not sure if string length can be checked statically anyways so i think the typing is perfectly alright, this issue can be closed unless some one else has a different opinion on it

[ondrejmirtes]

So if I get it correctly, strtok($nonEmptyString, ' ') should not have the false type. I can implement non-empty-string type pretty easily.

[aszenz]

Hmm, which functions would return this new type non-empty-string, or would we manually have to var annotate string variables that we think are non empty.

[ondrejmirtes]

There's going to be multiple ways to produce non-empty-string:

1. PHPDoc @param type
2. Check strlen($str) > 0 beforehand
3. Check $str !== '' beforehand

Without these, the strtok call will still have |false which will be correct.

[aszenz]

Aha, thanks for the explanation, so this narrows down the type after certain checks which is great.

I see php-stan recently added non-empty-array so I guess a non-empty-string would also be a nice feature to have.

[ondrejmirtes]

Implemented by: phpstan/phpstan-src@6ef5e91

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.