reference previous dataprovider by label

Author: staabm

src/Metadata/Api/DataProvider.php

@@ -197,8 +197,9 @@ private function dataProvidedByMethods(string $className, string $methodName, Me
 
                         throw InvalidDataProviderException::forProvider(
                             sprintf(
-                                'The key "%s" has already been defined by a previous data provider',
+                                'The key "%s" has already been defined by provider %s',
                                 $key,
+                                $result[$key]->getProviderLabel(),
                             ),
                             $providerLabel,
                         );

tests/end-to-end/event/data-provider-duplicate-key.phpt

@@ -19,7 +19,7 @@ Data Provider Method Finished for PHPUnit\TestFixture\Event\DataProviderDuplicat
 - PHPUnit\TestFixture\Event\DataProviderDuplicateKeyTest::provider
 Test Triggered PHPUnit Error (PHPUnit\TestFixture\Event\DataProviderDuplicateKeyTest::testSomething)
 The data provider PHPUnit\TestFixture\Event\DataProviderDuplicateKeyTest::provider specified for PHPUnit\TestFixture\Event\DataProviderDuplicateKeyTest::testSomething is invalid
-The key "key" has already been defined by a previous data provider
+The key "key" has already been defined by provider PHPUnit\TestFixture\Event\DataProviderDuplicateKeyTest::provider
 Test Runner Triggered Warning (No tests found in class "PHPUnit\TestFixture\Event\DataProviderDuplicateKeyTest".)
 Test Suite Loaded (0 tests)
 Test Runner Started

tests/unit/Metadata/Api/DataProviderTest.php

@@ -172,7 +172,7 @@ public function testWithVariousIterableNonStaticDataProviders(): void
     public function testWithDuplicateKeyDataProvider(): void
     {
         $this->expectException(InvalidDataProviderException::class);
-        $this->expectExceptionMessage('The key "foo" has already been defined by a previous data provider');
+        $this->expectExceptionMessage('The key "foo" has already been defined by provider PHPUnit\TestFixture\DuplicateKeyDataProviderTest::dataProvider');
 
         /* @noinspection UnusedFunctionResultInspection */
         (new DataProvider)->providedData(DuplicateKeyDataProviderTest::class, 'test');
@@ -204,7 +204,7 @@ public function testTestWithAttributeWithDuplicateKey(): void
     public function testWithDuplicateKeyDataProviders(): void
     {
         $this->expectException(InvalidDataProviderException::class);
-        $this->expectExceptionMessage('The key "bar" has already been defined by a previous data provider');
+        $this->expectExceptionMessage('The key "bar" has already been defined by provider PHPUnit\TestFixture\DuplicateKeyDataProvidersTest::dataProvider1');
 
         /* @noinspection UnusedFunctionResultInspection */
         (new DataProvider)->providedData(DuplicateKeyDataProvidersTest::class, 'test');