strval(mixed) errors since version 1.10.15

[mickverm]

Bug report

In version 1.10.15, PHPStan's handling of strval() changed (see phpstan/phpstan-src#2354)

Since then, the following does not work any longer on level 9:

$value = strval(constant('SECRET'));
Parameter #1 $value of function strval expects bool|float|int|resource|string|null, mixed given.

The following was never allowed:

$value = (string) constant('SECRET');
Cannot cast mixed to string.

This is now the only solution/fix, is this intended behavior?

/** @var string $value */
$value = constant('SECRET');

https://phpstan.org/r/32f21004-4041-4ef8-a83b-b53bd29f08c4

[mergeable]

This bug report is missing a link to reproduction at phpstan.org/try.

It will most likely be closed after manual review.

[pgrau]

Example of the issue:

https://phpstan.org/r/4736e47b-c63e-4674-bb84-8faa9e8c8902

The bug it happens with strval and intval too.

[herndlm]

@mickverm maybe the issue is about the constant function which could be improved potentially to be aware of the defined constants in the current scope? E.g. https://phpstan.org/r/0348777f-4d7b-43b9-942e-b1dcbe50a80c works fine

@pgrau I don't quite understand your example, do you maybe have a better one? Passing mixed to a function that does not except it, is unsafe IMO, consider e.g. https://3v4l.org/27TIY
To help with your use case generics might be useful too maybe? https://phpstan.org/r/96f37382-8086-40b7-90ad-1ee00918fc04

[pgrau]

@herndlm The type argument of strval function is mixed https://www.php.net/manual/en/function.strval.php then I don't understand why phpstan gives this error: Parameter #1 $value of function strval expects bool|float|int|resource|string|null, mixed given.

[Mte90]

The same issue happens also on intval.

If someone is looking for the rules to ignore the errors in the meantime for a fix:

- '/^Parameter #1 \$value of function strval expects bool\|float\|int\|resource\|string\|null, mixed given.$/'
- '/^Parameter #1 \$value of function intval expects array\|bool\|float\|int\|resource\|string\|null, mixed given.$/'

[ondrejmirtes]

Hello, this is an expected error and it would be unwise to just ignore it. If you chose to use level 9, you must be interested in fixing it instead.

PHP documentation isn't correct. Although it says strval(mixed $value): string, the function crashes for some input types, like: https://3v4l.org/Vpb2R

Same for intval: https://3v4l.org/Qe4ep (we don't want warnings either)

So first you need to make sure that your value is of the correct type, preferably by narrowing down the type using PHPDocs at the source.

[mickverm]

I ended up having to remove strval() everywhere, since not one of my use cases was valid anymore.
I'm surprised such a major change made it into PHPstan in a patch version.

[ondrejmirtes]

I'm surprised such a major change made it into PHPstan in a patch version

This is not a major change. Think of it this way - your usage was already dangerous and invalid, PHPStan just pointed it out. It's not safe to call strval etc. with mixed.

I'm very aware and careful about these breakages. But I decided this one is okay because level 9 users chose it because they want maximum safety, maybe even at the cost of developer experience.

For some context, not even PHPStan itself is checked on level 9, just on level 8. Level 9 is really brutal and not everyone needs to feel obligated to use it.