update-alternatives

Charles Wilson cygwin@cwilson.fastmail.fm
Sun Jun 26 23:12:00 GMT 2005


Buzz wrote:

> Well? What's up? Anybody there?
> 
> Do I need to provide more info?

I think it's a neat idea, but I don't think update-alternatives should 
use it.  I plan to, eventually, borrow some of the ideas you mention and 
integrate them into a similar program distributed as part of the 
alternatives package.  The reason I'm planning to do it that way rather 
than use your version directly, is because I don't want the 
"alternatives" package to have to manage TWO different databases. 
Further, since the "alternatives-wrap" program would be a cygwin prog, 
it can unwrap chains of symlinks itself and exec the actual target 
without using execvp().  Plus, alternatives itself needs to be smart 
about when to use a wrap executable, and when to use "normal" symlinks. 
  e.g. scripts should never be the target of a wrap, unless wrap is 
smart enough to parse sh-bang headers, and exec("/bin/bash -c 
real-target $@").  Regardless, sometimes you want alternatives to swap 
out man pages and such, and alternatives would definitely need to know 
NOT to use a wrap proggie in those cases.

So, (a) alternatives isn't set up, YET, to use any sort of wrap prog, 
and (b) when it is, it probably shouldn't use your wrap, directly. 
Worse, I'll need to come up with some extension to the database language 
used in /var/lib/alternatives/*, or add mucho smarts to 
update-alternatives, before even considering to use any wrap prog.

I think your wrap program is a fine tool, and I'd encourage you to ITP 
it (or submit it for inclusion within the cygutils package; IMO it's a 
good candidate for that).  I just don't think it does, exactly, what the 
alternatives package will eventually need.

--
Chuck



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