Support tag for AutowireLocator

[pkly]

Hey, I just noticed in our codebase after disabling tests marking code as used that a bunch of classes implementing interfaces no longer show as used, even though they are.

I traced it back to here

dead-code-detector/src/Provider/SymfonyUsageProvider.php

Line 547 in 021aa21

if (!isset($arguments['services']) || (!isset($arguments['defaultIndexMethod']) && !isset($arguments['defaultPriorityMethod']))) {

This bit doesn't support services by indexes. A combination of tag + indexAttribute (or no indexAttribute) can be used here to search for services with that tag and then mark them as used in terms of methods being used in the class, where the locator pulls out a service and calls on it (presumably an interface method).

We often use something like this

#[AutowireLocator('app.tagged.handler', indexAttribute: 'type')] private readonly ServiceLocator $handlersLocator,

so if this would be supported it'd be great.

[janedbal]

Can you show more specific example of method usage that is not seen by DCD?

[pkly]

Currently having issues with something like this

interface FooBarInterface {
    public function work(): void;
}

class Foo {
    /**
      * @param ServiceLocator<FooBarInterface> $locator
      */
    public function __construct(
        #[AutowireLocator('some.tag', indexAttribute: 'something')] private readonly ServiceLocator $locator
    )

    public function something(): void {
        $this->locator->get('whatever')->work();
    }
}

// assume the class is tagged properly for the time being
class Bar implements FooBarInterface {
    public function work(): void {} // marked as dead code
}

Even though the interface is properly tagged, the service locator works fine in regular use and the container xml is configured via the phpstan-symfony plugin config.

[janedbal]

This example works fine in my reproduction. Can you send minimal failing repo?

[pkly]

I'll try to prepare a reproduction for you on monday.

[pkly]

So, I took a bit of time to look into it, tried to simulate the exact scenario we have and came up with this
https://github.com/pkly/dead-code-detect-repro

However, this also does not report that error.
As I reran phpstan earlier on our main repo suddenly 4 more shipmonk.deadMethod calls were removed.

Regardless of that, I still see the dead code marker in our code.
I added a dump to DeadCodeRule:200 (with $knownCollectedUsages) and noticed that the calls for my interface method interfaceDiscover show up only twice

  5 => ShipMonk\PHPStan\DeadCode\Graph\CollectedUsage {#66128
    -usage: ShipMonk\PHPStan\DeadCode\Graph\ClassMethodUsage {#66127
      -origin: ShipMonk\PHPStan\DeadCode\Graph\UsageOrigin {#66131
        -className: "App\Discoverer"
        -memberName: "discover"
        -memberType: ShipMonk\PHPStan\DeadCode\Enum\MemberType {#11785
          +name: "METHOD"
          +value: 1
        }
        -accessType: ShipMonk\PHPStan\DeadCode\Enum\AccessType {#11790
          +name: "READ"
          +value: 1
        }
        -fileName: "/home/ly/Projects/personal/dead-code-detect-repro/src/Discoverer.php"
        -line: 23
        -provider: null
        -note: null
      }
      -callee: ShipMonk\PHPStan\DeadCode\Graph\ClassMethodRef {#66129
        -className: "App\Interface\DiscoverableInterface"
        -memberName: "interfaceDiscover"
        -possibleDescendant: true
      }
    }
    -excludedBy: null
  }
  20 => ShipMonk\PHPStan\DeadCode\Graph\CollectedUsage {#66058
    -usage: ShipMonk\PHPStan\DeadCode\Graph\ClassMethodUsage {#66070
      -origin: ShipMonk\PHPStan\DeadCode\Graph\UsageOrigin {#66071
        -className: "App\Tests\Discoverable\BasicDiscovererTest"
        -memberName: "testDiscover"
        -memberType: ShipMonk\PHPStan\DeadCode\Enum\MemberType {#11785}
        -accessType: ShipMonk\PHPStan\DeadCode\Enum\AccessType {#11790}
        -fileName: "/home/ly/Projects/personal/dead-code-detect-repro/tests/Discoverable/BasicDiscovererTest.php"
        -line: 14
        -provider: null
        -note: null
      }
      -callee: ShipMonk\PHPStan\DeadCode\Graph\ClassMethodRef {#66057
        -className: "App\Discoverable\BasicDiscoverer"
        -memberName: "interfaceDiscover"
        -possibleDescendant: false
      }
    }
    -excludedBy: "tests"
  }

I'm not sure if this is because you mark all classes that have an interface method as used? (I'm guessing).
I refreshed caches and reran phpstan which got rid of a few things, but this is still returning as not used.

I tried to set it up pretty much the same, with this repo I can't really see the service being marked as having been used?
If possible, please let me know where should I dump some data out that might assist with debugging.

[janedbal]

I can't really see the service being marked as having been used

You can use debug.usageOf to see all usages seen by DCD.