default field configuration fix

Author: nekufa

src/Space.php

@@ -70,6 +70,10 @@ public function addProperty(string $name, string $type, array $config = [])
             throw new Exception("Duplicate property $name");
         }
 
+        if (array_key_exists('default', $config) && !is_string($config['default'])) {
+            $config['default'] = (string) $config['default'];
+        }
+
         $this->format[] = $config;
         $this->mapper->client->call("box.space.$this->name:format", $this->format);
 

tests/MapperTest.php

@@ -35,6 +35,15 @@ public function createMapper(
         return $mapper;
     }
 
+    public function testDefaults()
+    {
+        $mapper = $this->createMapper();
+        $tester = $mapper->createSpace('tester');
+        $tester->addProperty('id', 'unsigned');
+        $tester->addProperty('number', 'unsigned', ['default' => 0]);
+        $tester->addProperty('string', 'string', ['default' => '']);
+    }
+
     public function testCache()
     {
         $mapper = $this->createMapper(dropUserSpaces: false);