Factor out a method to fetch type information

Author: chadwhitacre

postgres/__init__.py

@@ -835,7 +835,7 @@ def parse(self, s, curs, retry=False):
             tokens = self.tokenize(s)
             if len(tokens) != len(self.atttypes):
                 # The number of columns has changed, re-fetch the type info
-                self.__dict__.update(self._from_db(self.name, curs).__dict__)
+                self._refetch_type_info(curs)
 
             try:
                 values = [ curs.cast(oid, token)
@@ -844,7 +844,7 @@ def parse(self, s, curs, retry=False):
                 # The type of a column has changed, re-fetch it and retry once
                 if retry:
                     raise
-                self.__dict__.update(self._from_db(self.name, curs).__dict__)
+                self._refetch_type_info(curs)
                 return self.parse(s, curs, True)
 
             return self.make(values)
@@ -864,6 +864,12 @@ def make(self, values):
             instance = ModelSubclass(record)
             return instance
 
+        def _refetch_type_info(self, curs):
+            """Given a cursor, update the current object with a fresh type definition.
+            """
+            new_self = self._from_db(self.name, curs)
+            self.__dict__.update(new_self.__dict__)
+
     return DelegatingCaster