[buildd-tools-devel] [GIT] sbuild branch master updated. release/sbuild-0.68.0-10-ge2d63eb

[Colin Watson]

On Thu, Feb 18, 2016 at 07:53:16PM +0100, Johannes Schauer wrote:
> I don't think this change is a good solution. Apt might start using symlinks
> for the copy: URI as well in the future

Of course anything could happen in theory, but that would make no sense
at all; the entire purpose of copy: vs. file: is to tell apt not to
symlink.

> So instead, why not fix your problem where the actual breakage comes from:
> nobody but apt should access /var/lib/apt/lists as what is in there has never
> been guaranteed to be stable. See #752702 for more explanation from the apt
> maintainers.
> 
> So why implement a workaround in sbuild instead of fixing the source of the
> problem: launchpad-buildd?
> 
> Either let it correctly handle broken symlinks or (much better) use `apt-get
> indextargets` together with `/usr/lib/apt/apt-helper cat-file` to retrieve the
> information you want from /var/lib/apt/lists.

Neither of those would actually help, given that the apt archive has
been cleaned up by sbuild by the time the relevant code in
launchpad-buildd runs (it's doing some more detailed analysis of
dep-waits after sbuild failures; ideally we might use dose for this, but
there are some complications in our environment that make this approach
very much easier to arrange) and the information is therefore gone
unless it's copied.  Changing sbuild to cause apt not to create symlinks
was the simplest answer by some distance and doesn't break anything that
I can see.

Yes, we should probably use "apt-get indextargets" etc. rather than
directly poking in /var/lib/apt/lists/, but that only works in very
recent versions of apt, so we'd end up with multiple branches of code,
and we don't especially need further complication here.  Also, that's
essentially unrelated to the actual problem we were facing.

Could you explain what my patch breaks?  It seems quite harmless and so
I'm somewhat surprised by the vehemence of your reaction to it.  If a
small adjustment makes life a little easier nearby, why not?

Cheers,

-- 
Colin Watson                                       [cjwatson at debian.org]