Merge branch 'ticket_2587'

Conflicts:
	test/profiles.txt
	test/sql/test_selectable.py

1 files changed, 25 insertions, 8 deletions

diff --git a/lib/sqlalchemy/sql/util.py b/lib/sqlalchemy/sql/util.py
index 91740dc16..6f4d27e1b 100644
--- a/lib/sqlalchemy/sql/util.py
+++ b/lib/sqlalchemy/sql/util.py
@@ -200,15 +200,28 @@ def clause_is_present(clause, search):
 
     """
 
-    stack = [search]
-    while stack:
-        elem = stack.pop()
+    for elem in surface_selectables(search):
         if clause == elem:  # use == here so that Annotated's compare
             return True
-        elif isinstance(elem, expression.Join):
+    else:
+        return False
+
+def surface_selectables(clause):
+    stack = [clause]
+    while stack:
+        elem = stack.pop()
+        yield elem
+        if isinstance(elem, expression.Join):
             stack.extend((elem.left, elem.right))
-    return False
 
+def selectables_overlap(left, right):
+    """Return True if left/right have some overlapping selectable"""
+
+    return bool(
+                set(surface_selectables(left)).intersection(
+                        surface_selectables(right)
+                    )
+            )
 
 def bind_values(clause):
     """Return an ordered list of "bound" values in the given clause.
@@ -797,8 +810,11 @@ class ClauseAdapter(visitors.ReplacingCloningVisitor):
     def __init__(self, selectable, equivalents=None,
                         include=None, exclude=None,
                         include_fn=None, exclude_fn=None,
-                        adapt_on_names=False):
+                        adapt_on_names=False,
+                        traverse_options=None):
         self.__traverse_options__ = {'stop_on': [selectable]}
+        if traverse_options:
+            self.__traverse_options__.update(traverse_options)
         self.selectable = selectable
         if include:
             assert not include_fn
@@ -829,10 +845,11 @@ class ClauseAdapter(visitors.ReplacingCloningVisitor):
             newcol = self.selectable.c.get(col.name)
         return newcol
 
+    magic_flag = False
     def replace(self, col):
-        if isinstance(col, expression.FromClause) and \
+        if not self.magic_flag and isinstance(col, expression.FromClause) and \
             self.selectable.is_derived_from(col):
-                return self.selectable
+            return self.selectable
         elif not isinstance(col, expression.ColumnElement):
             return None
         elif self.include_fn and not self.include_fn(col):