ResourceMetadataCollection->getOperation: wrong cache hit with empty/null operationName

[usu]

API Platform version(s) affected: 3.0.4

Description
Calling getOperation with null or empty string as $operationName can lead to wrong cache hit.

How to reproduce

1. Specify a resource User with default CRUD operations
2. Run the following test code

class GetOperationTest extends ApiTestCase {
    public function test1GetOperationForGet() {
        $resourceMetadataCollection = $this->getResourceMetadataFactory()->create(User::class);

        $getOperation = $resourceMetadataCollection->getOperation(null, false, true);
        $this->assertInstanceOf(Get::class, $getOperation);
    }

    public function test2GetOperationForGetCollection() {
        $resourceMetadataCollection = $this->getResourceMetadataFactory()->create(User::class);

        $getCollectionOperation = $resourceMetadataCollection->getOperation(null, true, true);
        $this->assertInstanceOf(GetCollection::class, $getCollectionOperation);
    }

    public function test3GetOperationForBoth() {
        $resourceMetadataCollection = $this->getResourceMetadataFactory()->create(User::class);

        $getOperation = $resourceMetadataCollection->getOperation(null, false, true);
        $this->assertInstanceOf(Get::class, $getOperation);

        $getCollectionOperation = $resourceMetadataCollection->getOperation(null, true, true);
        $this->assertInstanceOf(GetCollection::class, $getCollectionOperation);
    }
}

3. Expected all tests to succeed. While test1 and test3 are running fine, test3 however fails with
   Failed asserting that ApiPlatform\Metadata\Get Object (...) is an instance of class "ApiPlatform\Metadata\GetCollection".

Possible Solution
The problem in test3 is that the first call of getOperation populates operationCache with an empty string as key:
return $this->operationCache[self::HTTP_PREFIX.$operationName] = $operation; where $operationName is empty string.

The second call to getOperation will immediately return the cache hit.

Possible solution:
Store the operation in operationCache with actual name of the operation, not with $operationName:
return $this->operationCache[self::HTTP_PREFIX.$operation->getName()] = $operation;

[soyuka]

you should always specify an operation name actually I'll fix this, you'd probably better using the OperationMetadataFactory.