Improve rendering of core statements w/ ORM elements

This patch contains a variety of ORM and expression layer
tweaks to support ORM constructs in select() statements,
without the 1.3.x requiremnt in Query that a full
_compile_context() + new select() is needed in order to
get a working statement object.

Includes such tweaks as the ability to implement
aliased class of an aliased class,
as we are looking to fully support ACs against subqueries,
as well as the ability to access anonymously-labeled
ColumnProperty expressions within subqueries by
naming the ".key" of the label after the property
key.   Some tuning to query.join() as well
as ORMJoin internals to allow things to work more
smoothly.

Change-Id: Id810f485c5f7ed971529489b84694e02a3356d6d

1 files changed, 9 insertions, 9 deletions

diff --git a/lib/sqlalchemy/sql/traversals.py b/lib/sqlalchemy/sql/traversals.py
index a38088a27..388097e45 100644
--- a/lib/sqlalchemy/sql/traversals.py
+++ b/lib/sqlalchemy/sql/traversals.py
@@ -18,6 +18,7 @@ NO_CACHE = util.symbol("no_cache")
 CACHE_IN_PLACE = util.symbol("cache_in_place")
 CALL_GEN_CACHE_KEY = util.symbol("call_gen_cache_key")
 STATIC_CACHE_KEY = util.symbol("static_cache_key")
+ANON_NAME = util.symbol("anon_name")
 
 
 def compare(obj1, obj2, **kw):
@@ -33,6 +34,7 @@ class HasCacheKey(object):
     _cache_key_traversal = NO_CACHE
     __slots__ = ()
 
+    @util.preload_module("sqlalchemy.sql.elements")
     def _gen_cache_key(self, anon_map, bindparams):
         """return an optional cache key.
 
@@ -54,6 +56,8 @@ class HasCacheKey(object):
 
         """
 
+        elements = util.preloaded.sql_elements
+
         idself = id(self)
 
         if anon_map is not None:
@@ -102,6 +106,10 @@ class HasCacheKey(object):
                         result += (attrname, obj)
                 elif meth is STATIC_CACHE_KEY:
                     result += (attrname, obj._static_cache_key)
+                elif meth is ANON_NAME:
+                    if elements._anonymous_label in obj.__class__.__mro__:
+                        obj = obj.apply_map(anon_map)
+                    result += (attrname, obj)
                 elif meth is CALL_GEN_CACHE_KEY:
                     result += (
                         attrname,
@@ -321,6 +329,7 @@ class _CacheKey(ExtendedInternalTraversal):
     ) = visit_operator = visit_plain_obj = CACHE_IN_PLACE
     visit_statement_hint_list = CACHE_IN_PLACE
     visit_type = STATIC_CACHE_KEY
+    visit_anon_name = ANON_NAME
 
     def visit_inspectable(self, attrname, obj, parent, anon_map, bindparams):
         return (attrname, inspect(obj)._gen_cache_key(anon_map, bindparams))
@@ -387,15 +396,6 @@ class _CacheKey(ExtendedInternalTraversal):
             attrname, obj, parent, anon_map, bindparams
         )
 
-    def visit_anon_name(self, attrname, obj, parent, anon_map, bindparams):
-        from . import elements
-
-        name = obj
-        if isinstance(name, elements._anonymous_label):
-            name = name.apply_map(anon_map)
-
-        return (attrname, name)
-
     def visit_fromclause_ordered_set(
         self, attrname, obj, parent, anon_map, bindparams
     ):