'start_commit' hook is unhookable?

[Brian de Alwis]

So I hacked together a tiny plugin to use the 'start_commit' hook to  
clear exec bits for a tree.  This failed on bzr 1.5, but I wrote the  
failure off at the time thinking that 'start_commit' must have been a  
new hook for 1.6.  But I've just installed 1.6b3 and the problem is  
there.  And poking around, I discovered that 'start_commit' was  
actually added in 1.4.

I get the following error in the log:

> [17636] 2008-08-02 11:40:23.992 WARNING: Unable to load plugin  
> 'clear_exec_bit'
> from '/Users/bsd/.bazaar/plugins'
> 0.494  Traceback (most recent call last):
>   File "/usr/pkg/lib/python2.4/site-packages/bzrlib/plugin.py", line  
> 210, in loa
> d_from_dir
>     exec "import bzrlib.plugins.%s" % name in {}
>   File "<string>", line 1, in ?
>   File "/Users/bsd/.bazaar/plugins/clear_exec_bit.py", line 23, in ?
>     Branch.hooks.install_named_hook(
>   File "/usr/pkg/lib/python2.4/site-packages/bzrlib/hooks.py", line  
> 75, in insta
> ll_named_hook
>     raise errors.UnknownHook(self.__class__.__name__, hook_name)
> UnknownHook: The BranchHooks hook 'start_commit' is unknown in this  
> version of b
> zrlib.

I'd hazard that the plugins are being loaded before the  
MutableTreeHooks.__init__() (which defines the 'start_commit' hook) is  
being called?

I've attached my simple plugin here.

------------------------------------------------------------
# For projects defining 'clear_exec_bit = on', this hook will first
# perform a `chmod a-x' for all files as a pre-commit hook.

import os
from bzrlib import urlutils
from bzrlib.branch import Branch
from bzrlib.config import LocationConfig

def start_commit_hook(tree):
     config = LocationConfig(tree.basedir) 	# unsure if this is right
     # maybe this should specify glob patterns instead...
     enabled = (config.get_user_option('clear_exec_bit') in
         (u'on', u'yes', u'ye', u'y'))
     if not enabled:
         return

     base = tree.basedir # it's how cmd_root does it
     # questionable whether single-quoting is the right thing
     print "clearing exec bits in " + base
     os.system("find '" + base + "' -type f -print0 | xargs -0 chmod a- 
x")

Branch.hooks.install_named_hook(
    'start_commit', start_commit_hook, 'clear executable bit')
------------------------------------------------------------


-- 
  Brian de Alwis | Software Practices Lab | UBC | http://www.cs.ubc.ca/~bsd/
       "Amusement to an observing mind is study." - Benjamin Disraeli