maas-devel team mailing list archive

[Raphaël Badin <raphael.badin@xxxxxxxxxxxxx>]

> > 2. Bug in our backport of the Django 1.4 method prefetch_related
> > The error: http://paste.ubuntu.com/1362899/
> > This can be exercised by running the test suite on a precise instance,
> > install 1.3.1-4ubuntu1.4~precise1+ppa1 (with includes the backport of
> > prefetch_related) and run the test suite of the 1.2 branch.
> > I /think/ this is because we need the feature introduced in
> > https://code.djangoproject.com/ticket/17003
> >   for prefetch_related to work.  This will need more investigation to be
> > fixed properly.
>
> I've fixed it, it was some code I had missed in the original backport.
> There's a new package available (by the time you read this) in the
> experimental PPA.

I think there are still some parts that are missing.

Running the test suite of the 1.2 branch on a precise instance (with the 
django package from the experimental ppa), I'm getting exceptions: 
AttributeError: 'ManyRelatedManager' object has no attribute 
'query_field_name' (http://paste.ubuntu.com/1369927/).

These failures go away if I comment out the calls to prefetch_related in 
MAAS' code.

This is the change that your patch does to the definition of the class 
'ManyRelatedManager':

    http://paste.ubuntu.com/1370197/

And in Django's sources, the commit 
662eea116f5a188b6983f5f7c01c8247e3b6b309 (which fixes 
https://code.djangoproject.com/ticket/16937 and introduces 
prefetch_related) changes the same code this way:

    http://paste.ubuntu.com/1370200/

I think you've missed part of the diff (namely the introduction of the 
field 'query_field_name').

R.