implement str-case functions return type extension

[staabm]

closes phpstan/phpstan#6987

[ondrejmirtes]

Don't sneak that in here, @craigfrancis would disagree ;)

[staabm]

I thought about the same thing and was not sure. but then I found

phpstan-src/src/Type/Php/ImplodeFunctionReturnTypeExtension.php

Lines 73 to 75 in 28f4503

	if ($arrayType->getIterableValueType()->isLiteralString()->yes() && $separatorType->isLiteralString()->yes()) {
	$accessoryTypes[] = new AccessoryLiteralStringType();
	}

which made me think this one here is fine.

maybe it is also wrong there?

[ondrejmirtes]

implode is one of the four functions that can produce literal strings as blessed by the original RFC: https://wiki.php.net/rfc/is_literal

[craigfrancis]

Yep, sorry, the only modification you can do that keep the literal-string flag is concatenation (this was done to help adoption, and is seen as acceptable by several security people, like the developers behind go-safe-html; where str_repeat(), str_pad(), implode(), and join() are all glorified forms of concatenation)... other modifications no longer result in a "fixed value in source code" (ref); and while the security properties of some functions (like strtoupper) might be ok, I would like to avoid the discussion of what functions are allowed vs what aren't :-)

[staabm]

thx for the insights

[ondrejmirtes]

@staabm Please send a PR to phpstan-doctrine after this is merged :)

[ondrejmirtes]

You don't need the if here. Using TypeCombinator::union() is more correct. You can have an edge case of calling lcfirst of 'foo'|'Foo' and the current code would result in 'foo'|'foo' which is bad :)

[staabm]

oh wow... how do you come up with such ideas...? well spotted!

[ondrejmirtes]

I guess the experience from doing this every day for the past 6 years 😅

[ondrejmirtes]

Thank you!

[craigfrancis]

I might be misreading something, but this seems to have changed with 1.7.x-dev (9ad2792):
https://phpstan.org/r/0dc8ccd0-37bb-49c8-bf2c-6bfb3ed459f0

[staabm]

I might be misreading something, but this seems to have changed with 1.7.x-dev (9ad2792):

what exactly do you mean?

[craigfrancis]

I'm trying to work on a different thing (using templates), so it might not be related... but lines 19-21 are doing what I expect with the output being seen as a string, but to do that I need to add something else to the strtolower() (I've used time)... the lines below, where I was using strtolower('B'), that's now being seen as a literal-string in this context.

[ondrejmirtes]

Because strtolower('B') becomes 'b' and that's a literal string. If you want to test against non-literal-string, you now need some code that PHPStan isn't able to figure out, like calling a function that just has string return type.

[craigfrancis]

Cool, thanks, I'll update some tests :-)