Create 2025-11-15-new-and-noteworthy-phpstan-phpunit-integration.md (#140)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: staabm

_posts/2025-11-15-phpstan-validates-phpunit-data-provider.md

@@ -0,0 +1,125 @@
+---
+tags:
+    - PHPStan
+    - PHPUnit
+
+image: "images/og-images/new-and-noteworthy-phpstan-phpunit-integration.jpg"
+
+ogImage:
+    title: "New and noteworthy: PHPStan and PHPUnit integration"
+    imageUrl: "https://staabm.github.io/staabm.svg"
+    fileName: "new-and-noteworthy-phpstan-phpunit-integration"
+---
+
+### New and noteworthy: PHPStan and PHPUnit integration
+
+In this article we will have a brief look into the latest update to [`phpstan/phpstan-phpunit`](https://github.com/phpstan/phpstan-phpunit) 2.0.8.
+
+### PHPStan validates PHPUnit data providers
+
+On of the features, which I am most proud of is the data provider validation.
+It was requested by several people years ago, but we did not yet have a good idea how to make it happen without major changes in the PHPStan core.
+
+Starting with this release, we take each data-set of a data-provider and check it against the signature of the corresponding test-case.
+
+At the time of writing we support multiple kind of data-providers:
+- `@test`
+- `#[Test]`
+- "test*" method name prefix
+- `@dataProvider`
+- `#[DataProvider]`
+- `static` data-provider
+- non-`static` data-provider
+- `return []` data-providers
+- `yield []` data-providers
+- `yield from []` data-providers
+- named arguments in data-providers
+
+```php
+	#[DataProvider('aProvider')]
+	public function testTrim(string $expectedResult, string $input): void
+	{
+	}
+
+	public function aProvider(): array /** @phpstan-ignore missingType.iterableValue */
+	{
+		return [
+			[
+				'Hello World',
+				" Hello World \n",
+			],
+			[
+			    // Parameter #2 $input of method FooTest::testTrim() expects string, int given.
+				'Hello World',
+				123,
+			],
+			[
+			    // Parameter #2 $input of method FooTest::testTrim() expects string, false given.
+				'Hello World',
+				false,
+			],
+			[
+			    // Method FooTest::testTrim() invoked with 1 parameter, 2 required.
+				'Hello World',
+			],
+		];
+	}
+```
+
+For this to happen we re-use existing rules for method call validation via the newly introduced [`NodeCallbackInvoker`](https://github.com/phpstan/phpstan-src/blob/2.1.x/src/Analyser/NodeCallbackInvoker.php).
+This new interface allows us to create virtual made-up AST nodes, which are handled like regular method calls.
+
+Related pull requests:
+- [Implement DataProviderDataRule](https://github.com/phpstan/phpstan-phpunit/pull/238)
+- [NodeCallbackInvoker](https://github.com/phpstan/phpstan-src/pull/4429)
+- [CompositeRule](https://github.com/phpstan/phpstan-src/pull/4438)
+
+
+### Ignore `missingType.iterableValue` for data-providers
+
+You likely have been haunted by this error in your test-suite:
+
+> Method DataProviderIterableValueTest\Foo::dataProvider() return type has no value type specified in iterable type iterable.
+
+Even in the PHPStan-src codebase this error was ignored by NEON config in the past, as it was really not that useful to repeat all types in every data-provider,
+which were already present in the test-case method signatures.
+
+As you already learned in the above paragraph we learned how to validate data-providers with this release.
+We went one step further and re-used the existing validation logic to omit the `missingType.iterableValue` error only for those data-providers which we are able to validate.
+This is possible by [implementing a new `IgnoreErrorExtension`](https://github.com/phpstan/phpstan-phpunit/pull/246).
+
+
+### Improved `assertArrayHasKey` inference
+
+Based on a [fix in the PHPStan core](https://github.com/phpstan/phpstan-src/pull/4473), we are now able to properly narrow types after a call to `assertArrayHasKey`.
+This will help to prevent false positive errors you may have experienced in the past.
+
+
+### PHPUnit version detector
+
+With the addition of [`PHPUnitVersionDetector`](https://github.com/phpstan/phpstan-phpunit/pull/248)
+we will be able to easily implement rules or extensions tailored to certain PHPUnit versions.
+
+This will be useful in the future, so we can for example assist in PHPUnit migrations and pave the way for a smoother upgrade path.
+
+
+### Performance improvements
+
+People reading my blog or social media posts know [my obsession in making things faster](https://staabm.github.io/archive.html#performance).
+This release is no difference, as some changes have been done to make most PHPUnit specific rules [more efficient by reducing unnecessary work](https://github.com/phpstan/phpstan-phpunit/pull/247).
+
+
+### Easter eggs included
+
+There is even more magic under the hood.
+
+We have a experimental feature in PHPStan which allows us to not just report errors, but also `--fix` some of them.
+This new ability was also added to a few `assert*` rules.
+
+
+### Summary
+
+I spent a lot of time over a few weeks to make the PHPUnit integration shine. I feel we are on a totally new level and even more new cool stuff is getting possible.
+
+Make sure your boss considers [sponsoring my open source work](https://github.com/sponsors/staabm), so I can spent more time no your beloved code quality tooling.
+