Do not delete metafields not managed

issue11019
review364431002

CHANGELOG

@@ -1,3 +1,4 @@
+* Define the metafields managed by Tryton
 * Add support for Python 3.10
 * Remove support for Python 3.6
 

tests/scenario_web_shop_shopify.rst

@@ -70,6 +70,12 @@ Set metafields to product::
 
     >>> Template.get_shopify_metafields = get_shopify_metafields
 
+    >>> from trytond.modules.web_shop_shopify.web import Shop
+    >>> def managed_metafields(self):
+    ...     return {'global.test'}
+
+    >>> Shop.managed_metafields = managed_metafields
+
 Create country::
 
     >>> belgium = Country(name="Belgium", code='BE')

web.py

@@ -115,13 +115,20 @@ class Shop(metaclass=PoolMeta):
                     and payment_journal.match(pattern)):
                 return payment_journal.journal
 
+    def managed_metafields(self):
+        return set()
+
     def __sync_metafields(self, resource, metafields):
+        metafields = metafields.copy()
+        managed_metafields = self.managed_metafields()
+        assert metafields.keys() <= managed_metafields
         for metafield in resource.metafields():
             key = '.'.join([metafield.namespace, metafield.key])
             value = metafield.to_dict()
             if key not in metafields:
-                metafield.destroy()
-                time.sleep(BACKOFF_TIME)
+                if key in managed_metafields:
+                    metafield.destroy()
+                    time.sleep(BACKOFF_TIME)
             elif metafields[key] != value:
                 for k, v in metafields.pop(key).items():
                     setattr(metafield, k, v)