- rewritten ClauseAdapter merged from the eager_minus_join branch; this is a much simpler

and "correct" version which will copy all elements exactly once, except for those which were
replaced with target elements.  It also can match a wider variety of target elements including
joins and selects on identity alone.

1 files changed, 6 insertions, 3 deletions

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index fa4ac5a9f..ef66ffd5a 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -87,10 +87,11 @@ OPERATORS =  {
     operators.isnot : 'IS NOT'
 }
 
-class DefaultCompiler(engine.Compiled, visitors.ClauseVisitor):
+class DefaultCompiler(engine.Compiled):
     """Default implementation of Compiled.
 
-    Compiles ClauseElements into SQL strings.
+    Compiles ClauseElements into SQL strings.   Uses a similar visit
+    paradigm as visitors.ClauseVisitor but implements its own traversal.
     """
 
     __traverse_options__ = {'column_collections':False, 'entry':True}
@@ -163,7 +164,9 @@ class DefaultCompiler(engine.Compiled, visitors.ClauseVisitor):
         if stack:
             self.stack.append(stack)
         try:
-            return self.traverse_single(obj, **kwargs)
+            meth = getattr(self, "visit_%s" % obj.__visit_name__, None)
+            if meth:
+                return meth(obj, **kwargs)
         finally:
             if stack:
                 self.stack.pop(-1)