aptitude has poor exit status behaviour

[Nick Boyce <nick@glimmer.demon.co.uk>]

In the course of scripting some aptitude upgrade activity I've found
that (Etch) aptitude's error handling [cough] falls short of optimum
behaviour.  In particular it returns an exit status of zero in various
failure situations, which is unhelpful, to say the least.

For example:

Although it helpfully returns 1 if you tell it nonsense ...

  # aptitude hshshsh
  Unknown command "hshshsh"
  aptitude 0.2.15.9
  ==> exit status 1

... and 'aptitude update' as non-root fails with 255 ...

  $ aptitude update
  E: Could not open lock file /var/lib/apt/lists/lock -
     open (13 Permission denied)
  E: Couldn't lock list directory..are you root?
  ==> exit status 255

... if you're behind a proxy firewall (such as inside my employer's
network) then various kinds of failure all exit with 0 ...

Here's 'aptitude update' as root but with the required firewall proxy
not specified in /etc/apt/apt.conf :

  # aptitude update
  Err http://ftp.de.debian.org etch Release.gpg
    Could not resolve 'ftp.de.debian.org'
  Err http://security.debian.org etch/updates Release.gpg
    Could not resolve 'security.debian.org'
  Ign http://ftp.de.debian.org etch Release
  Ign http://ftp.de.debian.org etch/main Packages/DiffIndex
  Err http://ftp.de.debian.org etch/main Packages
    Could not resolve 'ftp.de.debian.org'
  Ign http://security.debian.org etch/updates Release
  Ign http://security.debian.org etch/updates/main Packages/DiffIndex
  Ign http://security.debian.org etch/updates/contrib Packages/DiffIndex
  Err http://security.debian.org etch/updates/main Packages
    Could not resolve 'security.debian.org'
  Err http://security.debian.org etch/updates/contrib Packages
    Could not resolve 'security.debian.org'
  Reading package lists...
  ==> exit status 0

Here's 'aptitude update' with the firewall proxy specified but an
incorrect username/password :

  # aptitude update
  Ign http://ftp.de.debian.org etch Release.gpg
  Ign http://security.debian.org etch/updates Release.gpg
  Ign http://ftp.de.debian.org etch Release
  Ign http://security.debian.org etch/updates Release
  Ign http://ftp.de.debian.org etch/main Packages/DiffIndex
  Ign http://security.debian.org etch/updates/main Packages/DiffIndex
  Err http://ftp.de.debian.org etch/main Packages
    403 Forbidden
  Ign http://security.debian.org etch/updates/contrib Packages/DiffIndex
  Err http://security.debian.org etch/updates/main Packages
    403 Forbidden
  Err http://security.debian.org etch/updates/contrib Packages
    403 Forbidden
  Reading package lists... Done
  ==> exit status 0

Here's "aptitude update" with the firewall proxy specified but
the previously valid password has expired :
  # aptitude update
  Ign http://ftp.de.debian.org etch Release.gpg
  Ign http://security.debian.org etch/updates Release.gpg
  Ign http://ftp.de.debian.org etch Release
  Ign http://security.debian.org etch/updates Release
  Ign http://ftp.de.debian.org etch/main Packages/DiffIndex
  Ign http://security.debian.org etch/updates/main Packages/DiffIndex
  Err http://ftp.de.debian.org etch/main Packages
    407 Proxy Authentication Required
  Ign http://security.debian.org etch/updates/contrib Packages/DiffIndex
  Err http://security.debian.org etch/updates/main Packages
    407 Proxy Authentication Required
  Err http://security.debian.org etch/updates/contrib Packages
    407 Proxy Authentication Required
  Reading package lists... Done
  ==> exit status 0

At least that's what happens with my company's firewall. Surely
'aptitude' should be able to do better than that ?

I did a quick test with 'apt-get' on Sarge, and found it returns exit
status 100 in at least some of these situations (I didn't test all of
them), so there seems to have been some regression here :

  # apt-get update
  Err http://security.debian.org sarge/updates/main Packages
    407 Proxy Authentication Required
  Err http://de.samba.org sarge/samba Packages
    407 Proxy Authentication Required
   [...]
  Failed to fetch
  http://de.samba.org/samba/ftp/Binary_Packages/Debian/dists
   /sarge/samba/binary-i386/Packages.gz
    407 Proxy Authentication Required
  Reading Package Lists...
  E: Some index files failed to download, they have been ignored,
  or old ones used instead.
  ==> exit status 100

I found 3 related bug reports against aptitude, all apparently still open :

http://bugs.debian.org/233129
[wishlist; from Feb.2004; aptitude exits with zero on dialup connection
failure]

http://bugs.debian.org/282408
[minor; from Nov.2004; aptitude exits with zero if installation fails or
is cancelled by the user after downloading packages]

http://bugs.debian.org/445035
[important: from Oct.2007; aptitude exits with zero if installation
fails because nonexistent package requested]


Does anyone think another bug report is called for ?
It looks as though it's known that the error handling behaviour
needs attention but it's not high on anybody's TODO list.

And is there a better list to post this to ?  A check shows only
debian-dpkg(-bugs) or debian-qa(-packages) as being likely.

Any comments welcome.

Cheers,
Nick Boyce