Enhance connection closed by EM stracktrace.

src/Decorator/EntityManagerDecorator.php

@@ -9,6 +9,7 @@
 use Doctrine\ORM\EntityRepository;
 use Doctrine\ORM\Query\ResultSetMapping;
 use Doctrine\Persistence\ObjectManagerDecorator;
+use Throwable;
 
 use function func_get_arg;
 use function func_num_args;
@@ -184,9 +185,9 @@ public function getPartialReference($entityName, $identifier)
     /**
      * {@inheritDoc}
      */
-    public function close()
+    public function close(?Throwable $e = null)
     {
-        $this->wrapped->close();
+        $this->wrapped->close($e);
     }
 
     /**

src/EntityManager.php

@@ -152,6 +152,9 @@ class EntityManager implements EntityManagerInterface
      */
     private $cache;
 
+    /** @var EntityManagerClosed|null */
+    private $closedWhere = null;
+
     /**
      * Creates a new EntityManager that operates on the given database connection
      * and uses the given Configuration and EventManager implementations.
@@ -254,7 +257,7 @@ public function transactional($func)
 
             return $return ?: true;
         } catch (Throwable $e) {
-            $this->close();
+            $this->close($e);
             $this->conn->rollBack();
 
             throw $e;
@@ -637,11 +640,12 @@ public function clear($entityName = null)
     /**
      * {@inheritDoc}
      */
-    public function close()
+    public function close(?Throwable $e = null)
     {
         $this->clear();
 
-        $this->closed = true;
+        $this->closed      = true;
+        $this->closedWhere = EntityManagerClosed::createClosedHere($e);
     }
 
     /**
@@ -880,7 +884,7 @@ public function getConfiguration()
     private function errorIfClosed(): void
     {
         if ($this->closed) {
-            throw EntityManagerClosed::create();
+            throw EntityManagerClosed::createWhere($this->closedWhere);
         }
     }
 

src/EntityManagerInterface.php

@@ -16,6 +16,7 @@
 use Doctrine\ORM\Query\FilterCollection;
 use Doctrine\ORM\Query\ResultSetMapping;
 use Doctrine\Persistence\ObjectManager;
+use Throwable;
 
 /**
  * EntityManager interface
@@ -220,7 +221,7 @@ public function getPartialReference($entityName, $identifier);
      *
      * @return void
      */
-    public function close();
+    public function close(?Throwable $e = null);
 
     /**
      * Creates a copy of the given entity. Can create a shallow or a deep copy.

src/Exception/EntityManagerClosed.php

@@ -4,10 +4,38 @@
 
 namespace Doctrine\ORM\Exception;
 
+use Throwable;
+
 final class EntityManagerClosed extends ORMException implements ManagerException
 {
     public static function create(): self
     {
         return new self('The EntityManager is closed.');
     }
+
+    public static function createWhere(?Throwable $e = null): self
+    {
+        if ($e === null) {
+            return self::create();
+        }
+
+        return new self(
+            'The EntityManager is closed (previous allows to trace back to where it was closed).',
+            0,
+            $e
+        );
+    }
+
+    public static function createClosedHere(?Throwable $cause = null): self
+    {
+        if ($cause === null) {
+            return new self('This exception allows to trace back to where close() was called.');
+        }
+
+        return new self(
+            'This exception allows to trace back to where close() was called (see previous exception for the cause).',
+            0,
+            $cause
+        );
+    }
 }

tests/Performance/Mock/NonProxyLoadingEntityManager.php

@@ -7,6 +7,7 @@
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\Proxy\ProxyFactory;
 use Doctrine\ORM\Query\ResultSetMapping;
+use Throwable;
 
 /**
  * An entity manager mock that prevents lazy-loading of proxies
@@ -183,9 +184,9 @@ public function getPartialReference($entityName, $identifier)
     /**
      * {@inheritDoc}
      */
-    public function close()
+    public function close(?Throwable $e = null)
     {
-        $this->realEntityManager->close();
+        $this->realEntityManager->close($e);
     }
 
     /**

tests/Tests/ORM/Decorator/EntityManagerDecoratorTest.php

@@ -8,6 +8,7 @@
 use Doctrine\ORM\Decorator\EntityManagerDecorator;
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\Query\ResultSetMapping;
+use Exception;
 use Generator;
 use LogicException;
 use PHPUnit\Framework\MockObject\MockObject;
@@ -80,6 +81,15 @@ static function (): void {
             ];
         }
 
+        if ($method->getName() === 'close') {
+            return [
+                $method->getName(),
+                [
+                    new Exception(),
+                ],
+            ];
+        }
+
         $parameters = [];
 
         foreach ($method->getParameters() as $parameter) {