- added concept of 'require_embedded' to corresponding_column.

requires that the target column be present in a sub-element of the
target selectable.
- embedded logic above more appropriate for ClauseAdapter functionality
since its trying to "pull up" clauses that represent columns within
a larger union up to the level of the union itself.
- the "direction" test against the "foreign_keys" collection apparently
works for an exact "column 'x' is present in the collection", no proxy
relationships needed.  fixes the case of relating a selectable/alias
to one of its underlying tables, probably fixes other scenarios

1 files changed, 3 insertions, 3 deletions

diff --git a/lib/sqlalchemy/sql_util.py b/lib/sqlalchemy/sql_util.py
index 3eb4b6d06..70fc85702 100644
--- a/lib/sqlalchemy/sql_util.py
+++ b/lib/sqlalchemy/sql_util.py
@@ -178,7 +178,7 @@ class Aliasizer(AbstractClauseProcessor):
 
 class ClauseAdapter(AbstractClauseProcessor):
     """Given a clause (like as in a WHERE criterion), locate columns
-    which *correspond* to a given selectable, and changes those
+    which are embedded within a given selectable, and changes those
     columns to be that of the selectable.
 
     E.g.::
@@ -219,10 +219,10 @@ class ClauseAdapter(AbstractClauseProcessor):
         if self.exclude is not None:
             if col in self.exclude:
                 return None
-        newcol = self.selectable.corresponding_column(col, raiseerr=False, keys_ok=False)
+        newcol = self.selectable.corresponding_column(col, raiseerr=False, require_embedded=True, keys_ok=False)
         if newcol is None and self.equivalents is not None and col in self.equivalents:
             for equiv in self.equivalents[col]:
-                newcol = self.selectable.corresponding_column(equiv, raiseerr=False, keys_ok=False)
+                newcol = self.selectable.corresponding_column(equiv, raiseerr=False, require_embedded=True, keys_ok=False)
                 if newcol:
                     return newcol
         return newcol