Julian Field MailScanner at
Tue Oct 21 14:31:20 IST 2008

Mark Nienberg wrote:
> I think on a centOS system the is doing this for the perl 
> modules that conflict with the base perl:
> check to see if the perl module is installed,
> see that it isn't,
> build an rpm for the module from the downloaded src,
> attempt to install the rpm, but the install fails due to conflict with 
> installed perl,
> force install only for those that absolutely need it.
> I'm wondering if the process could be shorted to eliminate building 
> the rpm for the module if the rpm already exists in 
> /usr/src/redhat/RPMS (probably from a previous MailScanner install).
No, because then if something went wrong with the install (in that a 
corrupt RPM got built somehow), then re-installing wouldn't help the 
situation, and you would have to get into all sorts of messing around 
deleting files to get yourself out of the hole.
> Alternatively, could the initial check for the module be improved 
> somehow to detect that the module is already installed as part of the 
> the core perl installation? I suspect that must not be possible or 
> Jules would have done it already.
Not easy. You can't find where a Perl module is installed, just that it 
*is* installed.
> Also, the installer builds rpms for packages that will not install due 
> to already installed rpms.  For example, on my system it builds
> perl-IO-stringy-2.110-1
> and tries to install it, but discovers that
> perl-IO-stringy-2.110-1.2.el5.rf
> is already installed.
> Could the installer test for already installed rpms before building 
> and attempting installation of the new one?
> In the above example it would run "rpm -q perl-IO-stringy" and then do 
> some sort of version checking.
The version checking you need to do is far from trivial. 2.10 is greater 
than 2.9, but not in numerical or alphabetical terms. It's quite a 
tricky problem. I really don't want to open that Pandora's box! :-)

Nice ideas though...

P.S. Sorry I haven't been around here much recently. I'm a bit run down, 
and I have the impending prospect of major surgery (liver transplant for 
those of you who don't already know) and all the pain that goes with 
that. Plus I've got my kittens to look after, which consume quite a lot 
of my available energy. If there's anything serious, you can always mail 
me directly, and I do always read all of that, even if I don't keep up 
with the list every day at the moment.
P.P.S. Thank you to all of you who answer everyone's queries and 
problems on my behalf, it is greatly appreciated!


Julian Field MEng CITP CEng
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