[buildd-tools-devel] Bug#859866: Bug#859866: sbuild transiently fails stating apt-get update failed

[David Kalnischkies]

On Tue, Apr 11, 2017 at 10:43:12AM +0200, Johannes Schauer wrote:
> >     Reading package lists...
> >     E: Could not open file /var/lib/apt/lists/deb.debian.org_debian_dists_sid_main_source_Sources.diff_Index - open (2: No such file or directory)
> >     E: apt-get update failed
[…]
> > Find a full session transcript attached.
> 
> I never encountered this error message. Neither from running sbuild nor from
> running apt-get update.
> 
> Maybe apt people have a clue about what this means? I CC-ed their list.

Haven't seen that either yet. There are a few observations I can make
through:

- ignoring the error, the command seems to be successful
- the chroots last update seems to be a while ago – the contrib patches
  downloaded go back a month which has infrequent updates, but main has
  changes all the time, so in all likelyhood (if apt reaches that stage)
  apt would figure out that the Index doesn't include the starting file
  anymore and fall back to full download (as it does in many other
  situations)
- the error message is about the "final" directory, not partial/.


Combined, I have the wild guess that apt sees a reason to fallback to
the full download, but while winding down the patch handling something
tries to access the file (or a previous version of it) which happens to
be discarded already. But: I had a quick look and nothing which
immediatly caught my eye codewise (more "proofs" that this can't be it
actually) & I ran a quick test with the too old situation I described
above which was completed successfully without errors from a user PoV…


As I have no idea, I would suggest running apt with an extended set of
debug options and hope that this gives a better hint at what could be
wrong:

Debug::pkgAcquire "true";
Debug::pkgAcquire::Diffs "true";
Debug::pkgAcquire::Worker "true";
Debug::Acquire::Transaction "true";
Debug::Acquire::http "true";

(the later two aren't a typo. There is a reason the "pkg" is missing
from them – just don't ask me why as I have no idea ;) )

Assuming this is reproducible. I fear it isn't… (running apt with these
options isn't dangerous or anything if someone wanted to try for longer,
they just make apt super chatty about some things.)


Best regards

David Kalnischkies
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