Bazaar spontaneously unusable

[Jelmer Vernooij]

On Thu, 2010-03-25 at 22:19 +1000, Ian Clatworthy wrote:
> Russel Winder wrote:
> > I appreciate that using bzr.dev is bleeding edge but the recent change
> > of bzrlib version has rendered a number of plugins unusable:
> > 
> > Unable to load plugin 'svn'. It requested API version (2, 1, 0) of module <module 'bzrlib' from '/home/Checkouts/Bazaar/Bazaar/Mainline_Working/bzrlib/__init__.pyc'> but the minimum exported version is (2, 2, 0), and the maximum is (2, 2, 0)
> > Unable to load plugin 'git'. It requested API version (2, 1, 0) of module <module 'bzrlib' from '/home/Checkouts/Bazaar/Bazaar/Mainline_Working/bzrlib/__init__.pyc'> but the minimum exported version is (2, 2, 0), and the maximum is (2, 2, 0)
> > Unable to load plugin 'rewrite'. It requested API version (2, 1, 0) of module <module 'bzrlib' from '/home/Checkouts/Bazaar/Bazaar/Mainline_Working/bzrlib/__init__.pyc'> but the minimum exported version is (2, 2, 0), and the maximum is (2, 2, 0)
> > Unable to load plugin 'loggerhead'. It requested API version (2, 1, 0) of module <module 'bzrlib' from '/home/Checkouts/Bazaar/Bazaar/Mainline_Working/bzrlib/__init__.pyc'> but the minimum exported version is (2, 2, 0), and the maximum is (2, 2, 0)
> Personally, I'm not a fan of our "default to failure" approach. I find
> this truly annoying and think it's an anti-pattern.
We should probably have more granular versioning so when an API changes
not everything claims it's incompatible but just those things that use
that API. That has its costs as well, though.

I don't think we should remove the version checking altogether - it
prevents quite a few confused users that are using incompatible versions
of bzr and plugins.

> Surely we can engineer a robust system without breaking half of our
> popular plugins every six months like this? Our current process doesn't
> scale. Imagine the scenario if we had 10 times as many plugins as now.
> I'm certainly pleased that my Firefox plugins continue working 99% of
> the time after each new Firefox release.
Actually, Firefox seems to work in a very similar way as we do. I've
been running Lucid with Firefox 3.7 for a while now, and most of my
plugins still can not be loaded because they're not marked as working
with 3.7. 

Cheers,

Jelmer