fix(MethodClassReflectionExtension): Fix bug with how many_many 'thro…

…ugh' logic works - Github Issue #13

- Update documentation to include known limitations

README.md

@@ -50,6 +50,10 @@ The pattern will be as follows until I no longer need to maintain support for Si
 * [Advanced Usage](docs/en/advanced-usage.md)
 * [License](LICENSE.md)
 
+## Known Limitations
+
+* The type of the `owner` property can't be reasoned about for extensions. You must use `getOwner()`. Related Issues: [#1043](https://github.com/phpstan/phpstan/issues/1043) and [#1044](https://github.com/phpstan/phpstan/issues/1044)
+
 ## Credits
 
 * [Ondřej Mirtes](https://github.com/ondrejmirtes) for his amazing work on the PHPStan library

src/Reflection/MethodClassReflectionExtension.php

@@ -127,14 +127,24 @@ private function createMethods(ClassReflection $classReflection): array
 
                 foreach ($componentNameValueMap as $methodName => $type) {
                     if (is_array($type)) {
-                        if (!isset($type['through'])) {
-                            throw new Exception('Unknown array format. Expected string or array with "through".');
+                        if ($componentType !== 'many_many') {
+                            throw new Exception('Cannot use array format for "'.$componentType.'" component type.');
+                        }
+                        if (!isset($type['through']) ||
+                            !isset($type['from']) ||
+                            !isset($type['to'])) {
+                            throw new Exception('Unknown array format. Expected string or array with "through", "from" and "to".');
                         }
                         // Example data:
                         // array(3) {["through" => "SilverStripe\Assets\Shortcodes\FileLink"]
                         //           ["from" => "Parent"]
                         //           ["to" => "Linked"]
-                        $type = $type['through'];
+                        $toClass = $type['to'];
+                        $throughClass = $type['through'];
+                        $throughClassHasOne = ConfigHelper::get($throughClass, 'has_one');
+                        if ($throughClassHasOne && isset($throughClassHasOne[$toClass])) {
+                            $type = $throughClassHasOne[$toClass];
+                        }
                     }
                     // Ignore parameters
                     $type = explode('(', $type, 2);

tests/Reflection/SiteTreeMethodClassReflectionExtensionTest.php

@@ -91,12 +91,9 @@ public function testLinkTrackingMethod(): void
             // This statement is needed so PHPStan knows $resultType is ObjectType.
             return;
         }
-        self::assertContains(
+        self::assertSame(
             $resultType->getClassName(),
-            [
-                ClassHelper::SiteTree, // Expected value for: SilverStripe 4.0
-                ClassHelper::SiteTreeLink, // Expected value for: SilverStripe 4.2+ (master branch at time of writing, 4.2+ is an assumption)
-            ]
+            ClassHelper::SiteTree
         );
     }
 }