[storm] suspected bug in caching behavior

[Andreas Kopecky]

Hi,

James Henstridge schrieb:
<snip />
 >
 > This sounds a bit like https://bugs.launchpad.net/storm/+bug/277095
 > which has been fixed on trunk since the 0.13 release.
 >
 > If you have the time, would you mind trying to reproduce the bug with
 > the development version of Storm?  Alternatively, you could try
 > applying the changes from
 > http://bazaar.launchpad.net/~storm/storm/trunk/revision/271 to the
 > 0.13 release and see if that helps.

Thanks for the quick answer. Bug description does sound quite familiar
yes. Am i right to assume that the fix you suspect is

270. By  Thomas Herve  on 2008-10-02

     Reset checkpoint states of variables when updating a field with
     a lazy value:
     this fixes a problem with an update reverting a field value to
     a previously cached value.

If yes i will patch my 0.13 with the changes of that revision and see
how it works out.

For completeness a quick guide to reproduce this behavior:

make a storm object with field bar, value foo.
  - load this object and update bar to fuu
  - load object again update bar to foo again
  - load object a third time, update to fuu a second time
if you are faster then garbage collection the value will
not be changed but stay at 'foo' because you get an artifact
of ObjectInfo with a faulty _checkpoint state.

Sounds very much like the bug you sent me back yet i am not so
sure if it is good to fix that via a reset of _checkpoint_state.

The bug lies within the usage of WeakValueDictionary - or rather
not clearing it over transaction boundaries while using it as
de facto cache

- regards
Andreas Kopecky

P.S. On a side note i just love Storm - we are doing a rather big Zope
project here and i replaced a ZODB implemenation of the datamodel with
Storm 1.5 years into the project and it just worked like a charm - just
wanted to tell you ;)