fix: allow nullable erasure request user relationship in serializers

src/Api/Serializer/ExportSerializer.php

@@ -37,12 +37,12 @@ protected function getDefaultAttributes($export)
         return $attributes;
     }
 
-    protected function user($export): Relationship
+    protected function user($export): ?Relationship
     {
         return $this->hasOne($export, BasicUserSerializer::class);
     }
 
-    protected function actor($export): Relationship
+    protected function actor($export): ?Relationship
     {
         return $this->hasOne($export, BasicUserSerializer::class);
     }

src/Api/Serializer/RequestErasureSerializer.php

@@ -36,12 +36,12 @@ protected function getDefaultAttributes($erasure_request)
         ];
     }
 
-    protected function user($erasure_request): Relationship
+    protected function user($erasure_request): ?Relationship
     {
         return $this->hasOne($erasure_request, BasicUserSerializer::class);
     }
 
-    protected function processedBy($erasure_request): Relationship
+    protected function processedBy($erasure_request): ?Relationship
     {
         return $this->hasOne($erasure_request, BasicUserSerializer::class);
     }

src/Http/Controller/ExportController.php

@@ -36,7 +36,7 @@ public function handle(ServerRequestInterface $request): ResponseInterface
                 200,
                 [
                     'Content-Type'        => 'application/zip',
-                    'Content-Length'      => $this->storageManager->getStoredExportSize($export),
+                    'Content-Length'      => (string) $this->storageManager->getStoredExportSize($export),
                     'Content-Disposition' => 'attachment; filename="data-export-'.$export->user->username.'-'.$export->created_at->toIso8601String().'.zip"',
                 ]
             );

tests/integration/api/ProcessErasureTest.php

@@ -85,6 +85,28 @@ public function authorized_users_can_see_confirmed_erasure_requests()
         $this->assertEquals(ErasureRequest::STATUS_USER_CONFIRMED, $json['data'][0]['attributes']['status']);
     }
 
+    /**
+     * @test
+     */
+    public function authorized_users_can_see_confirmed_erasure_requests_even_if_user_was_deleted()
+    {
+        $this->send($this->request('GET', '/api/forum'));
+        User::query()->where('id', 5)->delete();
+
+        $response = $this->send(
+            $this->request('GET', '/api/user-erasure-requests', [
+                'authenticatedAs' => 3,
+            ])
+        );
+
+        $this->assertEquals(200, $response->getStatusCode());
+
+        $json = json_decode($response->getBody()->getContents(), true);
+
+        $this->assertCount(1, $json['data']);
+        $this->assertEquals(ErasureRequest::STATUS_USER_CONFIRMED, $json['data'][0]['attributes']['status']);
+    }
+
     /**
      * @test
      */