[pacman-dev] [PATCH] alpm_checkdeps clean-up

Nagy Gabor ngaba at bibl.u-szeged.hu
Fri Nov 30 19:07:09 EST 2007

Fri, 30 Nov 2007 22:45:06 +0100 -n
Xavier <shiningxc at gmail.com> írta:

> On Fri, Nov 30, 2007 at 08:37:13AM -0600, Dan McGee wrote:
> > I'll be looking at it this weekend for sure. The "check localdb by
> > hand" comment scares me a bit, but I haven't dove into the code yet.
> > 
> Maybe some pseudo-code could help, but not sure if it's a good idea.
> compute_requiredby(pkg) :
> for p in localdb
>   for dep in p.deps
>     if pkg satisfies dep
>       add p to the return list
> checkdeps :
> for p in {upgrade U remove}
>   for q in compute_requiredby(p)
>     for dep in q.deps
>       if p satisfies dep
>         /* check if dep is still satisfied by another pkg */
> The minor problems with the above :
> 1) the localdb is scanned n times, with n = length of upgrade +
> remove lists. 2) the dependency that is the cause of q being required
> by p is lost (the "for dep in q.deps; if p satisfies dep ..." is done
> twice : first in compute_requiredby , then again in checkdeps)
> Instead of that, the localdb just needs to be scanned once. And for
> each package, we check if it depends on a package going to be
> upgraded or removed.
Some other small "issues":
And when you compute requiredby you needn't check the whole db, dblist
(see my patch) is enough (what's more: needed), which can be much
smaller with -Su for example [however, you must dblist once]
And compute_requiredby returns with a list of strings (grr), and you
must do pkgcache scan for find the package.

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