Unify generation between Core and ORM query

generation is to be enhanced to include caching
functionality, so ensure that Query and all generative in Core
(e.g. select, DML etc) are using the same generations system.

Additionally, deprecate Select.append methods and state
Select methods independently of their append versions.
Mutability of expression objects is a special case only when
generating new objects during a visit.

Fixes: #4637
Change-Id: I3dfac00d5e0f710c833b236f7a0913e1ca24dde4

1 files changed, 11 insertions, 6 deletions

diff --git a/lib/sqlalchemy/sql/base.py b/lib/sqlalchemy/sql/base.py
index da384bdab..7e9199bfa 100644
--- a/lib/sqlalchemy/sql/base.py
+++ b/lib/sqlalchemy/sql/base.py
@@ -43,13 +43,18 @@ def _from_objects(*elements):
     return itertools.chain(*[element._from_objects for element in elements])
 
 
-@util.decorator
-def _generative(fn, *args, **kw):
-    """Mark a method as generative."""
+def _generative(fn):
+    @util.decorator
+    def _generative(fn, *args, **kw):
+        """Mark a method as generative."""
 
-    self = args[0]._generate()
-    fn(self, *args[1:], **kw)
-    return self
+        self = args[0]._generate()
+        fn(self, *args[1:], **kw)
+        return self
+
+    decorated = _generative(fn)
+    decorated.non_generative = fn
+    return decorated
 
 
 def _clone(element, **kw):