From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Mon, 4 Jun 2007 15:20:42 +0000 (+0000)
Subject: join() will check existing objects in the FROM clause and not re-join to one which... 
X-Git-Tag: rel_0_4_6~225
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e4ca785747b15fb8e9eb913e716b42422fc57ea;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

join() will check existing objects in the FROM clause and not re-join to one which is already present
---

diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index a26bf8dcb6..f2e87b7dea 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -535,23 +535,28 @@ class Query(object):
         else:
             [keys,p] = self._locate_prop(prop, start=start)
         clause = self._from_obj[-1]
+
+        currenttables = sql_util.TableFinder(self._from_obj, include_aliases=True)
+            
         mapper = start
         for key in keys:
             prop = mapper.props[key]
             if prop._is_self_referential():
                 raise exceptions.InvalidRequestError("Self-referential query on '%s' property must be constructed manually using an Alias object for the related table." % str(prop))
-            if outerjoin:
-                if prop.secondary:
-                    clause = clause.outerjoin(prop.secondary, prop.get_join(mapper, primary=True, secondary=False))
-                    clause = clause.outerjoin(prop.select_table, prop.get_join(mapper, primary=False))
-                else:
-                    clause = clause.outerjoin(prop.select_table, prop.get_join(mapper))
-            else:
-                if prop.secondary:
-                    clause = clause.join(prop.secondary, prop.get_join(mapper, primary=True, secondary=False))
-                    clause = clause.join(prop.select_table, prop.get_join(mapper, primary=False))
+            # dont re-join to a table already in our from objects
+            if prop.select_table not in currenttables:
+                if outerjoin:
+                    if prop.secondary:
+                        clause = clause.outerjoin(prop.secondary, prop.get_join(mapper, primary=True, secondary=False))
+                        clause = clause.outerjoin(prop.select_table, prop.get_join(mapper, primary=False))
+                    else:
+                        clause = clause.outerjoin(prop.select_table, prop.get_join(mapper))
                 else:
-                    clause = clause.join(prop.select_table, prop.get_join(mapper))
+                    if prop.secondary:
+                        clause = clause.join(prop.secondary, prop.get_join(mapper, primary=True, secondary=False))
+                        clause = clause.join(prop.select_table, prop.get_join(mapper, primary=False))
+                    else:
+                        clause = clause.join(prop.select_table, prop.get_join(mapper))
             mapper = prop.mapper
         return (clause, mapper)
 
diff --git a/lib/sqlalchemy/sql_util.py b/lib/sqlalchemy/sql_util.py
index 9f8bf276ec..7a67402318 100644
--- a/lib/sqlalchemy/sql_util.py
+++ b/lib/sqlalchemy/sql_util.py
@@ -71,7 +71,7 @@ class TableFinder(TableCollection, sql.NoColumnVisitor):
         TableCollection.__init__(self)
         self.check_columns = check_columns
         self.include_aliases = include_aliases
-        if clause is not None:
+        for clause in util.to_list(clause):
             self.traverse(clause)
 
     def visit_alias(self, alias):