[core] check properly the object id when deciding to clone or not the Pin

Author: Emanuele Palazzetti

ddtrace/pin.py

@@ -71,7 +71,7 @@ def get_from(obj):
         pin_name = _DD_PIN_PROXY_NAME if isinstance(obj, wrapt.ObjectProxy) else _DD_PIN_NAME
         pin = getattr(obj, pin_name, None)
         # detect if the PIN has been inherited from a class
-        if pin is not None and pin._target is not obj:
+        if pin is not None and pin._target != id(obj):
             pin = pin.clone()
             pin.onto(obj)
         return pin

tests/test_instance_config.py

@@ -24,6 +24,14 @@ def test_configuration_get_from(self):
         cfg = config.get_from(self.Klass)
         ok_(isinstance(cfg, dict))
 
+    def test_configuration_get_from_twice(self):
+        # ensure the configuration is the same if `get_from` is used
+        # in the same instance
+        instance = self.Klass()
+        cfg1 = config.get_from(instance)
+        cfg2 = config.get_from(instance)
+        ok_(cfg1 is cfg2)
+
     def test_configuration_set(self):
         # ensure the configuration can be updated in the Pin
         instance = self.Klass()