Trusty: apt does not try next mirror if index file download fails with mirror:// source

Marking dev + xenial as Invalid since it works from Xenial onward

"Marking dev + xenial as Invalid since it works from Xenial onward"

You marked trusty and dev as invalid, and kept xenial open? Unfortunately, there have been huge changes in the acquire system in 1.1, so there is likely no way to fix this in trusty.

Notably, there has been no related change of the mirror method since the trusty release. So if it started working later, than that is related to the reworked acquire system.

As such, I'd like this bug to be closed as invalid, as it's not worth it. The pre 1.1 acquire system cannot really deal with failures gracefully.

You could of course try wily, if it works there, you're lucky, and can backport the fix.

Julian,

first of all, you are right, I did mix up the series, I'll fix that.

Now, Michael Vogt (mvo), Debian's APT main developer is currently reviewing the one line fix that solves this issue.

I have a reproducer and was able to identify the root cause and prepare a fix.

The source of the problem is the following :

    string msg = "\nIndex-File: true";
    // FIXME: this really should use "IndexTarget::IsOptional()" but that
    // seems to be difficult without breaking ABI
    if (ShortDesc().find("Translation") != 0)

As outlined in the FIXME, IndexTarget::IsOptional() should be used, and that is what started to happen with Wily. The code now reads :

   if(Target.IsOptional)
      msg += "\nFail-Ignore: true";

Here is the complete explanation as provided to MVO :

"When the Queue responsible for fetching the Package file runs, it builds the
Custom600 header with the following method :

> // AcqIndex::Custom600Headers - Insert custom request headers /*{{{*/
> // ---------------------------------------------------------------------
> /* The only header we use is the last-modified header. */
> string pkgAcqIndex::Custom600Headers()
> {
> string Final = _config->FindDir("Dir::State::lists");
> Final += URItoFileName(RealURI);
> if (_config->FindB("Acquire::GzipIndexes",false))
> Final += ".gz";
>
> string msg = "\nIndex-File: true";
> // FIXME: this really should use "IndexTarget::IsOptional()" but that
> // seems to be difficult without breaking ABI
> if (ShortDesc().find("Translation") != 0)
> msg += "\nFail-Ignore: true";
> struct stat Buf;
> if (stat(Final.c_str(),&Buf) == 0)
> msg += "\nLast-Modified: " + TimeRFC1123(Buf.st_mtime);
>
> return msg; ...

Hello Louis, or anyone else affected,

Accepted apt into trusty-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/apt/1.0.1ubuntu2.15 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

Patch verified through this sequence:

Add "deb http://archive.ubuntu.com/ubuntu trusty-proposed multiverse restricted main universe" to /etc/apt/sources.list

apt-get update
apt-get install apt=1.0.1ubuntu2.15
apt-get upgrade <- Accept all from maintainer

After that sequence, the apt-get update works without failure, even when one of the mirrors is partly broken.

The verification of the Stable Release Update for apt has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

This bug was fixed in the package apt - 1.0.1ubuntu2.15

---------------
apt (1.0.1ubuntu2.15) trusty; urgency=medium

  * Fixes failure to download the Package index file when using
    mirror:// URL in sources.list and the archive fails to profile
    a file. APT would try the next archive in the list for .deb
    packages but did not retry when the index file failed to download.
    (LP: #1625667)

 -- Louis Bouchard <email address hidden> Tue, 20 Sep 2016 17:02:03 +0200