RFC: centralise registries

[Vincent Ladeuil]

>>>>> "robert" == Robert Collins <robert.collins at canonical.com> writes:

    robert> On Wed, 2009-04-15 at 08:12 +0200, Vincent Ladeuil wrote:
    >> Then create bzrlib/selftest.py, put the registry there, and lazy
    >> load bzrlib.tests there ?
    >> 
    >> That seems to be the less of 3 or 4 evils :-/
    >> 
    >> That will at least address your initial concern (if I remember
    >> correctly): avoid loading the tests only to register a test suite
    >> decorator from a plugin.

    robert> Its *one* of many registries that are
    robert> problematic.

Don't shout ! :) I was throwing *another* idea in the mix not
*the* idea.

    robert> And adding a bunch of separate python files will just
    robert> add to performance headaches, not remove.

AFAIK several ideas has been proposed to address the slow load
problem, none have been completely implemented. And I seem to
remember that you were keen to consider the whole code base as
loaded, always.

Until then, I don't think adding one more python file will change
the size of problem.

*BUT* loading all the test code when loading a plugin at *each*
bzr invocation has certainly a cost *today*.

    robert> I want to find a small, clean, scalable fix. I think
    robert> a load time callback may be it.

I don't disagree :)

It's a known and powerful concept (called eval-after-load in
emacs) and that's certainly an alternative to some forms of lazy
loading.

  Vincent