Updating an array in foreach is wrongly inferred when strict mode is used.

[VincentLanglet]

Bug report

In the following example
https://phpstan.org/r/ec2a3c8e-4b32-443f-81b1-f2ba78836f3e
the array is understood as

Dumped type: array<string, array{foo: string, bar: ''}>

but with strict mode we're getting
https://phpstan.org/r/5a249928-665b-4b87-aff3-9e98b53c7fad

Dumped type: array<string, array{foo: string, bar?: ''}>

we have to update the array to a non-empty-array in order to get the right result
https://phpstan.org/r/0302aab8-0877-413b-9dff-ad41d7a8afcf

Code snippet that reproduces the problem

https://phpstan.org/r/5a249928-665b-4b87-aff3-9e98b53c7fad

Expected output

I expect to get

array<string, array{foo: string, bar: ''}>

even if the array in the foreach is empty.

Because if the array is empty, it's [] and it respect the definition array<string, array{foo: string, bar: ''}>.

This would avoid an error on the following code: https://phpstan.org/r/483aa742-4928-47f0-a0b2-02a07d8a684f

Did PHPStan help you today? Did it make you happy in any way?

No response

[ondrejmirtes]

This is a well known shortcoming. PHPStan does not understand when a whole array is being overwritten in a foreach.

If you create a new array and assign all the values to it, it's going to understand it well.

[VincentLanglet]

This is a well known shortcoming. PHPStan does not understand when a whole array is being overwritten in a foreach.

That was I thought, but then why does PHPStan seems to understand the whole-update when strict mode is not enabled ?
https://phpstan.org/r/ec2a3c8e-4b32-443f-81b1-f2ba78836f3e

If it's possible in non-strict mode, maybe it could in strict mode too (?)

[ondrejmirtes]

No idea, looks like a bug inside a bug

[VincentLanglet]

No idea, looks like a bug inside a bug

I'll be curious to take a look, any idea where I should look at in the phpstan-src code for those "array-type-update" ?

Edit: Since it's related to polluteScopeWithAlwaysIterableForeach: true options, it might be in NodeScopeResolver.

[ondrejmirtes]

Here's the foreach handling: https://github.com/phpstan/phpstan-src/blob/26d72e822ab547c2472b3cc4c3cf19ea7be79f8c/src/Analyser/NodeScopeResolver.php#L985-L1075

It's best to set a breakpoint and look at the result of $scope->debug() to see what's going on.

[VincentLanglet]

Here's the foreach handling: phpstan/phpstan-src@26d72e8/src/Analyser/NodeScopeResolver.php#L985-L1075

It's best to set a breakpoint and look at the result of $scope->debug() to see what's going on.

Thanks, I have some ideas I'd like to test but I have difficulties writing a NodeScopeResolver test.

Is there a way to add a test here https://github.com/phpstan/phpstan-src/blob/26d72e822ab547c2472b3cc4c3cf19ea7be79f8c/tests/PHPStan/Analyser/NodeScopeResolverTest.php#L13 but asking for polluteScopeWithAlwaysIterableForeach: false ? Or where should I add my test ?

[ondrejmirtes]

Create a new class extending TypeInferenceTestCase, creating a config file, reference the config file in getAdditionalConfigFiles

[VincentLanglet]

Thanks, I found something phpstan/phpstan-src#3029

[ondrejmirtes]

Fixed phpstan/phpstan-src#3029

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