fix: OOM crash in RemoveUnusedVariableAssignRector

Author: calebdw

rules/DeadCode/Rector/Assign/RemoveUnusedVariableAssignRector.php

@@ -13,26 +13,27 @@
 use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Expr\Include_;
 use PhpParser\Node\Expr\MethodCall;
-use PhpParser\Node\Expr\New_;
 use PhpParser\Node\Expr\NullsafeMethodCall;
 use PhpParser\Node\Expr\StaticCall;
 use PhpParser\Node\Expr\Variable;
+use PhpParser\Node\Name;
 use PhpParser\Node\Stmt;
 use PhpParser\Node\Stmt\Class_;
 use PhpParser\Node\Stmt\ClassMethod;
 use PhpParser\Node\Stmt\Expression;
 use PhpParser\Node\Stmt\Function_;
 use PhpParser\NodeVisitor;
+use PHPStan\Reflection\AttributeReflection;
 use PHPStan\Reflection\ClassReflection;
+use PHPStan\Reflection\ReflectionProvider;
 use PHPStan\Type\ObjectType;
 use Rector\DeadCode\SideEffect\SideEffectNodeDetector;
 use Rector\NodeAnalyzer\VariableAnalyzer;
 use Rector\NodeManipulator\StmtsManipulator;
 use Rector\Php\ReservedKeywordAnalyzer;
-use Rector\Php80\NodeAnalyzer\PhpAttributeAnalyzer;
-use Rector\PhpParser\AstResolver;
 use Rector\PhpParser\Enum\NodeGroup;
 use Rector\PhpParser\Node\BetterNodeFinder;
+use Rector\PHPStan\ScopeFetcher;
 use Rector\Rector\AbstractRector;
 use Rector\ValueObject\MethodName;
 use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
@@ -49,8 +50,7 @@ public function __construct(
         private readonly VariableAnalyzer $variableAnalyzer,
         private readonly BetterNodeFinder $betterNodeFinder,
         private readonly StmtsManipulator $stmtsManipulator,
-        private readonly AstResolver $astResolver,
-        private readonly PhpAttributeAnalyzer $phpAttributeAnalyzer
+        private readonly ReflectionProvider $reflectionProvider,
     ) {
     }
 
@@ -273,16 +273,8 @@ function (Node $subNode) use (&$refVariableNames) {
                 continue;
             }
 
-            if ($assign->expr instanceof FuncCall
-                || $assign->expr instanceof StaticCall
-                || $assign->expr instanceof MethodCall
-                || $assign->expr instanceof New_
-                || $assign->expr instanceof NullsafeMethodCall) {
-                $targetCall = $this->astResolver->resolveClassMethodOrFunctionFromCall($assign->expr);
-                if (($targetCall instanceof ClassMethod || $targetCall instanceof Function_)
-                    && $this->phpAttributeAnalyzer->hasPhpAttribute($targetCall, 'NoDiscard')) {
-                    continue;
-                }
+            if ($this->isNoDiscardCall($assign->expr)) {
+                continue;
             }
 
             $assignedVariableNamesByStmtPosition[$key] = $variableName;
@@ -306,4 +298,71 @@ private function shouldSkipVariable(Variable $variable, string $variableName, ar
 
         return in_array($variableName, $refVariableNames, true);
     }
+
+    private function isNoDiscardCall(Expr $expr): bool
+    {
+        if ($expr instanceof FuncCall) {
+            if (! $expr->name instanceof Name) {
+                return false;
+            }
+
+            $scope = ScopeFetcher::fetch($expr);
+
+            if (! $this->reflectionProvider->hasFunction($expr->name, $scope)) {
+                return false;
+            }
+
+            return $this->hasNoDiscardAttribute(
+                $this->reflectionProvider->getFunction($expr->name, $scope)
+                    ->getAttributes()
+            );
+        }
+
+        if ($expr instanceof StaticCall) {
+            $classNames = $this->getType($expr->class)
+                ->getObjectClassNames();
+            $methodName = $this->getName($expr->name);
+        } elseif ($expr instanceof MethodCall || $expr instanceof NullsafeMethodCall) {
+            $classNames = $this->getType($expr->var)
+                ->getObjectClassNames();
+            $methodName = $this->getName($expr->name);
+        } else {
+            return false;
+        }
+
+        if ($classNames === [] || $methodName === null) {
+            return false;
+        }
+
+        foreach ($classNames as $className) {
+            if (! $this->reflectionProvider->hasClass($className)) {
+                continue;
+            }
+
+            $classReflection = $this->reflectionProvider->getClass($className);
+            if (! $classReflection->hasNativeMethod($methodName)) {
+                continue;
+            }
+
+            if ($this->hasNoDiscardAttribute($classReflection->getNativeMethod($methodName)->getAttributes())) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @param AttributeReflection[] $attributes
+     */
+    private function hasNoDiscardAttribute(array $attributes): bool
+    {
+        foreach ($attributes as $attribute) {
+            if ($attribute->getName() === 'NoDiscard') {
+                return true;
+            }
+        }
+
+        return false;
+    }
 }