- Fixed exception throw which would occur when string-based

primaryjoin condition was used in conjunction with backref.

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/sqlalchemy/ext/declarative.py b/lib/sqlalchemy/ext/declarative.py
index 65af2da7a..85ccea648 100644
--- a/lib/sqlalchemy/ext/declarative.py
+++ b/lib/sqlalchemy/ext/declarative.py
@@ -374,6 +374,12 @@ def _deferred_relation(cls, prop):
             if isinstance(v, basestring):
                 setattr(prop, attr, resolve_arg(v))
 
+        if prop.backref:
+            for attr in ('primaryjoin', 'secondaryjoin'):
+               if attr in prop.backref.kwargs and isinstance(prop.backref.kwargs[attr], basestring):
+                   prop.backref.kwargs[attr] = resolve_arg(prop.backref.kwargs[attr])
+
+
     return prop
 
 def synonym_for(name, map_column=False):