Pool finalization sometimes raises exception during GC

[Andrey Popp]

I'm getting weird exceptions during my application exiting: Exception TypeError: "'NoneType' object is not callable" in <function <lambda> at 0x10389cb18> ignored ... Exception TypeError: "'NoneType' object is not callable" in <function <lambda> at 0x10389c398> ignored

This is due to finalization of _ConnectionFairy weakref which doesn't check if _finalize_fairy is still here.

[Andrey Popp]

Oops, sorry for description formatting.

[Mike Bayer]

weird, you mean after the module tears down it's called ? can't do the "x if y else z" due to py2.4, but anyway how about this:

diff -r 996d3916a33dfaa90bc59a1545c6c492fdf4aa1a lib/sqlalchemy/pool.py
--- a/lib/sqlalchemy/pool.py    Mon Jan 23 16:35:16 2012 -0500
+++ b/lib/sqlalchemy/pool.py    Mon Jan 23 18:22:15 2012 -0500
@@ -370,9 +370,10 @@
         try:
             rec = self._connection_record = pool._do_get()
             conn = self.connection = self._connection_record.get_connection()
+            _f_f = _finalize_fairy
             rec.fairy = weakref.ref(
                             self, 
-                            lambda ref:_finalize_fairy(conn, rec, pool, ref, _echo)
+                            lambda ref:_f_f(conn, rec, pool, ref, _echo)
                         )
             _refs.add(rec)
         except:

[Andrey Popp]

No, this doesn't work for me either:

Exception AttributeError: "'NoneType' object has no attribute 'discard'" in <function <lambda> at 0x1038fa938> ignored

but this does and compatible with py2.4:

...
rec.fairy = weakref.ref(
      self,
      lambda ref: _finalize_fairy and _finalize_fairy(conn, rec, pool, ref, _echo)
    )
...

[Mike Bayer]

this is really annoying that even a weakref needs to doubt local variables in it's own callback - what version of Python /platform is this ?

also you are going to fix your app to close the connection, right ? :)

[Andrey Popp]

Python 2.6.2/2.7.1 on FreeBSD/Mac OS X, and I've already fixed app to close connections. :-)

[Mike Bayer]

5221f492ca704d75561d7729fba0fa48fd3ad0fb

[Mike Bayer]

Removing milestone: 0.7.5 (automated comment)