implements basic immutability inheritance

Author: svnldwg

src/Helper/AnnotationParser.php

@@ -40,11 +40,8 @@ public static function propertiesWithWhitelistedAnnotations(array $annotations,
             return $whitelistedProperties;
         }
 
-        foreach ($classNode->stmts as $property) {
-            if (!$property instanceof Node\Stmt\Property) {
-                continue;
-            }
-
+        $classProperties = NodeParser::getClassProperties($classNode);
+        foreach ($classProperties as $property) {
             $whitelisted = self::isWhitelisted($property, $annotations);
             if ($whitelisted) {
                 foreach ($property->props as $prop) {
@@ -58,6 +55,7 @@ public static function propertiesWithWhitelistedAnnotations(array $annotations,
 
     /**
      * @param Node $node
+     *
      * @return string[]
      */
     public static function getAnnotations(Node $node): array

src/Helper/NodeParser.php

@@ -40,4 +40,31 @@ public static function getClassNode(array $nodes): ?Node\Stmt\Class_
 
         return null;
     }
+
+    /**
+     * @param Node\Stmt\Class_ $classNode
+     *
+     * @return Node\Stmt\Property[]
+     */
+    public static function getClassProperties(Node\Stmt\Class_ $classNode): array
+    {
+        $properties = [];
+
+        foreach ($classNode->stmts as $property) {
+            if ($property instanceof Node\Stmt\Property) {
+                $properties[] = $property;
+            }
+        }
+
+        return $properties;
+    }
+
+    public static function getNonPrivateProperties(Node\Stmt\Class_ $classNode): array
+    {
+        $properties = self::getClassProperties($classNode);
+
+        return array_filter($properties, static function (Node\Stmt\Property $property): bool {
+            return !$property->isPrivate();
+        });
+    }
 }

src/Rules/ImmutableObjectRule.php

@@ -11,6 +11,7 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use Svnldwg\PHPStan\Helper\AnnotationParser;
+use Svnldwg\PHPStan\Helper\NodeParser;
 
 /**
  * @template-implements Rule<Node>
@@ -45,11 +46,15 @@ public function processNode(Node $node, Scope $scope): array
             return [];
         }
 
+        $immutableProperties = $this->getParentClasses($scope);
+
         $nodes = $this->parser->parseFile($scope->getFile());
 
-        $immutableProperties = null;
         if (!AnnotationParser::classHasAnnotation(self::WHITELISTED_ANNOTATIONS, $nodes)) {
-            $immutableProperties = AnnotationParser::propertiesWithWhitelistedAnnotations(self::WHITELISTED_ANNOTATIONS, $nodes);
+            $immutableProperties = array_merge(
+                $immutableProperties,
+                AnnotationParser::propertiesWithWhitelistedAnnotations(self::WHITELISTED_ANNOTATIONS, $nodes)
+            );
 
             if (empty($immutableProperties)) {
                 return [];
@@ -106,4 +111,38 @@ public function processNode(Node $node, Scope $scope): array
             ))->build(),
         ];
     }
+
+    private function getParentClasses(Scope $scope): array
+    {
+        if ($scope->getClassReflection() === null) {
+            return [];
+        }
+
+        $immutableParentProperties = [];
+
+        // TODO: consider multiple layers of inheritance (parent 1 is not declared immutable, but parent 2 is, so properties of parent 1 need to inherit immutability
+
+        foreach ($scope->getClassReflection()->getParents() as $parent) {
+            $fileName = $parent->getFileName();
+            if (!$fileName) {
+                continue;
+            }
+
+            $nodes = $this->parser->parseFile($fileName);
+            $classNode = NodeParser::getClassNode($nodes);
+            if (!$classNode) {
+                continue;
+            }
+
+            if (AnnotationParser::classHasAnnotation(self::WHITELISTED_ANNOTATIONS, $nodes)) {
+                $immutableParentProperties += array_map(static function (Node\Stmt\Property $property): string {
+                    return (string)reset($property->props)->name;
+                }, NodeParser::getNonPrivateProperties($classNode));
+            }
+
+            // @TODO: detect non private parent properties annotated as immutable
+        }
+
+        return $immutableParentProperties;
+    }
 }

test/Integration/Rules/ImmutableObjectRuleTest.php

@@ -57,13 +57,13 @@ public function provideCasesWhereAnalysisShouldFail(): iterable
                     22,
                 ],
             ],
-            /*'mutation-in-child-class' => [
-                __DIR__ . '/../../Fixture/ImmutableObjectRule/Failure/MutationInChildClass.php',
+            'mutation-in-child-class' => [
+                __DIR__ . '/../../Fixture/ImmutableObjectRule/Failure/MutationInChildClassChild.php',
                 [
-                    'Class is declared immutable, but class property "value" is modified in method "setValue"',
-                    26,
+                    'Property is declared immutable, but class property "value" is modified in method "setValue"',
+                    11,
                 ],
-            ],*/
+            ],
         ];
 
         foreach ($paths as $description => [$path, $error]) {