Fix serialization issue of InvalidTag

src/DocBlock/Tags/InvalidTag.php

@@ -4,7 +4,10 @@ declare(strict_types=1);
 
 namespace phpDocumentor\Reflection\DocBlock\Tags;
 
+use Closure;
 use phpDocumentor\Reflection\DocBlock\Tag;
+use ReflectionClass;
+use ReflectionFunction;
 use Throwable;
 
 /**
@@ -56,12 +59,54 @@ final class InvalidTag implements Tag
 
     public function withError(Throwable $exception) : self
     {
+        $this->flattenExceptionBacktrace($exception);
         $tag            = new self($this->name, $this->body);
         $tag->throwable = $exception;
 
         return $tag;
     }
 
+    /**
+     * Removes all complex types from backtrace
+     *
+     * Not all objects are serializable. So we need to remove them from the
+     * stored exception to be sure that we do not break existing library usage.
+     */
+    private function flattenExceptionBacktrace(Throwable $exception) : void
+    {
+        $traceProperty = (new ReflectionClass('Exception'))->getProperty('trace');
+        $traceProperty->setAccessible(true);
+
+        $flatten = static function (&$value) {
+            if ($value instanceof Closure) {
+                $closureReflection = new ReflectionFunction($value);
+                $value             = sprintf(
+                    '(Closure at %s:%s)',
+                    $closureReflection->getFileName(),
+                    $closureReflection->getStartLine()
+                );
+            } elseif (is_object($value)) {
+                $value = sprintf('object(%s)', get_class($value));
+            } elseif (is_resource($value)) {
+                $value = sprintf('resource(%s)', get_resource_type($value));
+            }
+        };
+
+        do {
+            $trace = array_map(
+                static function($call) use ($flatten) {
+                    array_walk_recursive($call['args'], $flatten);
+
+                    return $call;
+                },
+                $exception->getTrace()
+            );
+            $traceProperty->setValue($exception, $trace);
+        } while ($exception = $exception->getPrevious());
+
+        $traceProperty->setAccessible(false);
+    }
+
     public function render(?Formatter $formatter = null) : string
     {
         if ($formatter === null) {

tests/unit/DocBlock/Tags/InvalidTagTest.php

@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace phpDocumentor\Reflection\DocBlock\Tags;
 
 use Exception;
+use InvalidArgumentException;
 use PHPUnit\Framework\TestCase;
 
 /**
@@ -28,6 +29,7 @@ final class InvalidTagTest extends TestCase
 
     /**
      * @covers ::withError
+     * @covers ::__toString
      */
     public function testCreationWithError() : void
     {
@@ -36,6 +38,59 @@ final class InvalidTagTest extends TestCase
 
         self::assertSame('name', $tag->getName());
         self::assertSame('@name Body', $tag->render());
+        self::assertSame('Body', (string)$tag);
         self::assertSame($exception, $tag->getException());
     }
+
+    public function testCreationWithErrorContainingClosure() : void
+    {
+        try {
+            $this->throwExceptionFromClosureWithClosureArgument();
+        } catch (Exception $e) {
+            $parentException = new Exception('test', 0, $e);
+            $tag       = InvalidTag::create('Body', 'name')->withError($parentException);
+            self::assertSame('name', $tag->getName());
+            self::assertSame('@name Body', $tag->render());
+            self::assertSame($parentException, $tag->getException());
+            self::assertStringStartsWith('(Closure at', $tag->getException()->getPrevious()->getTrace()[0]['args'][0]);
+            self::assertStringContainsString(__FILE__, $tag->getException()->getPrevious()->getTrace()[0]['args'][0]);
+            self::assertEquals($parentException, unserialize(serialize($parentException)));
+        }
+    }
+
+    private function throwExceptionFromClosureWithClosureArgument()
+    {
+        $function = function() {
+            throw new InvalidArgumentException();
+        };
+
+        $function($function);
+    }
+
+    public function testCreationWithErrorContainingResource()
+    {
+        try {
+            $this->throwExceptionWithResourceArgument();
+        } catch (Exception $e) {
+            $parentException = new Exception('test', 0, $e);
+            $tag       = InvalidTag::create('Body', 'name')->withError($parentException);
+            self::assertSame('name', $tag->getName());
+            self::assertSame('@name Body', $tag->render());
+            self::assertSame($parentException, $tag->getException());
+            self::assertStringStartsWith(
+                'resource(stream)',
+                $tag->getException()->getPrevious()->getTrace()[0]['args'][0])
+            ;
+            self::assertEquals($parentException, unserialize(serialize($parentException)));
+        }
+    }
+
+    private function throwExceptionWithResourceArgument()
+    {
+        $function = function() {
+            throw new InvalidArgumentException();
+        };
+
+        $function(fopen(__FILE__, 'r'));
+    }
 }