Fix vimeo#302 - add a way to seal objects with magic properties

src/Psalm/Checker/CommentChecker.php

@@ -296,6 +296,10 @@ public static function extractClassLikeDocblockInfo($comment, $line_number)
             $info->deprecated = true;
         }
 
+        if (isset($comments['specials']['psalm-seal-properties'])) {
+            $info->sealed_properties = true;
+        }
+
         if (isset($comments['specials']['psalm-suppress'])) {
             /** @var string $suppress_entry */
             foreach ($comments['specials']['psalm-suppress'] as $suppress_entry) {

src/Psalm/Checker/Statements/Expression/AssignmentChecker.php

@@ -661,9 +661,9 @@ public static function analyzePropertyAssignment(
                 if ($lhs_var_id !== '$this' &&
                     MethodChecker::methodExists($project_checker, $lhs_type_part . '::__set')
                 ) {
-                    if ($var_id) {
-                        $class_storage = $project_checker->classlike_storage_provider->get((string)$lhs_type_part);
+                    $class_storage = $project_checker->classlike_storage_provider->get((string)$lhs_type_part);
 
+                    if ($var_id) {
                         if (isset($class_storage->pseudo_property_set_types['$' . $prop_name])) {
                             $class_property_types[] =
                                 clone $class_storage->pseudo_property_set_types['$' . $prop_name];
@@ -674,7 +674,14 @@ public static function analyzePropertyAssignment(
 
                         $context->vars_in_scope[$var_id] = Type::getMixed();
                     }
-                    continue;
+
+                    /*
+                     * If we have an explicit list of all allowed magic properties on the class, and we're
+                     * not in that list, fall through
+                     */
+                    if (!$var_id || !$class_storage->sealed_properties) {
+                        continue;
+                    }
                 }
 
                 $has_regular_setter = true;

src/Psalm/Checker/Statements/Expression/FetchChecker.php

@@ -246,7 +246,13 @@ public static function analyzePropertyFetch(
                         $stmt->inferredType = Type::getMixed();
                     }
 
-                    continue;
+                    /*
+                     * If we have an explicit list of all allowed magic properties on the class, and we're
+                     * not in that list, fall through
+                     */
+                    if (!$class_storage->sealed_properties) {
+                        continue;
+                    }
                 }
             }
 

src/Psalm/ClassLikeDocblockComment.php

@@ -20,6 +20,11 @@ class ClassLikeDocblockComment
      */
     public $properties = [];
 
+    /**
+     * @var bool
+     */
+    public $sealed_properties = false;
+
     /**
      * @var array<int, string>
      */

src/Psalm/Storage/ClassLikeStorage.php

@@ -47,6 +47,11 @@ class ClassLikeStorage
      */
     public $deprecated = false;
 
+    /**
+     * @var bool
+     */
+    public $sealed_properties = false;
+
     /**
      * @var array<int, string>
      */

src/Psalm/Visitor/DependencyFinderVisitor.php

@@ -225,6 +225,8 @@ public function enterNode(PhpParser\Node $node)
 
                     $storage->deprecated = $docblock_info->deprecated;
 
+                    $storage->sealed_properties = $docblock_info->sealed_properties;
+
                     $storage->suppressed_issues = $docblock_info->suppressed_issues;
                 }
             }

tests/AnnotationTest.php

@@ -147,7 +147,8 @@ public function __set($name, $value) : void {
                     }
 
                     $a = new A();
-                    $a->foo = "hello";',
+                    $a->foo = "hello";
+                    $a->bar = "hello"; // not a property',
             ],
             'ignoreNullableReturn' => [
                 '<?php
@@ -421,6 +422,50 @@ public function __set(string $name, $value) : void {
                     $a->foo = 5;',
                 'error_message' => 'InvalidPropertyAssignment',
             ],
+            'propertySealedDocblockUndefinedPropertyAssignment' => [
+                '<?php
+                    /**
+                     * @property string $foo
+                     * @psalm-seal-properties
+                     */
+                    class A {
+                         public function __get(string $name) : ?string {
+                              if ($name === "foo") {
+                                   return "hello";
+                              }
+                         }
+
+                         /** @param mixed $value */
+                         public function __set(string $name, $value) : void {
+                         }
+                    }
+
+                    $a = new A();
+                    $a->bar = 5;',
+                'error_message' => 'UndefinedPropertyAssignment',
+            ],
+            'propertySealedDocblockUndefinedPropertyFetch' => [
+                '<?php
+                    /**
+                     * @property string $foo
+                     * @psalm-seal-properties
+                     */
+                    class A {
+                         public function __get(string $name) : ?string {
+                              if ($name === "foo") {
+                                   return "hello";
+                              }
+                         }
+
+                         /** @param mixed $value */
+                         public function __set(string $name, $value) : void {
+                         }
+                    }
+
+                    $a = new A();
+                    echo $a->bar;',
+                'error_message' => 'UndefinedPropertyFetch',
+            ],
             'noStringParamType' => [
                 '<?php
                     function fooFoo($a) : void {