bash package install fails [bash_4.3-6ubuntu1_amd64]

[Gil Pinheiro]

Aptitude fails during package upgrade.

Preconfiguring packages ...
(Reading database ... 286860 files and directories currently installed.)
Preparing to unpack .../bash_4.3-6ubuntu1_amd64.deb ...
Unpacking bash (4.3-6ubuntu1) over (4.3-4ubuntu2) ...
dpkg: error processing archive /var/cache/apt/archives/bash_4.3-6ubuntu1_amd64.deb (--unpack):
 unable to install (supposed) new info file `/var/lib/dpkg/tmp.ci/conffiles': Is a directory
Processing triggers for man-db (2.6.6-1) ...
Processing triggers for install-info (5.2.0.dfsg.1-2) ...
Errors were encountered while processing:
 /var/cache/apt/archives/bash_4.3-6ubuntu1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install. Trying to recover:

[Gil Pinheiro (gilpinheiro)]

If others are not seeing this problem, I have a theory and a solution. Okay, so I'm not sure how it happened, running dpkg under strace revealed that for whatever reason a directory was created named /var/lib/dpkg/info/bash.conffiles which caused dpkg to fail to install. My solution was just to delete that directory. The content of the directory was actually junk, which would lead me to believe this occured as a result of file system corruption (btrfs).

My recommendation would be to improve the error log - the failure was within the /var/lib/dpkg/info directory (i.e. in dpkg sources (unpack.c) in pkg_infodb_update it would be a good idea to log both the source (cidir) and target (cidirrest). That way future errors like this will be easier to diagnose.

This may be a one-off issue, but it may be helpful for anyone googling for this error message in future. If confirmed that this doesn't in fact impact bash, please redirect the recommendation to the dpkg maintainer.