[Bug 1616679] Re: rdepends for apt-cache fails for virtual packages

[Launchpad Bug Tracker]

Status changed to 'Confirmed' because the bug affects multiple users.

** Changed in: apt (Ubuntu)
       Status: New => Confirmed

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Title:
  rdepends for apt-cache fails for virtual packages

Status in apt package in Ubuntu:
  Confirmed

Bug description:
  Example of problem:

  The zimbra-mta package provides mail-transport-agent.

  Packages that depend on mail-transport-agent are installed
  (mailutils,logwatch).

  apt-cache is unable to list either of those as depending on zimbra-
  mta:

  root at zre-ldap004:/home/build# apt-cache rdepends --installed mail-transport-agent
  <mail-transport-agent>

  
  aptitude does a little better:

  root at zre-ldap004:/home/build# aptitude why zimbra-mta
  iB  mailutils  Depends  default-mta | mail-transport-agent
  ip  zimbra-mta Provides mail-transport-agent

  
  so it finds mailutils (but not logwatch).  so 50% better than apt-cache

  If we try to remove zimbra-mta, we find:

  root at zre-ldap004:/home/build# dpkg --purge zimbra-mta
  dpkg: dependency problems prevent removal of zimbra-mta:
   mailutils depends on default-mta | mail-transport-agent; however:
    Package default-mta is not installed.
    Package mail-transport-agent is not installed.
    Package zimbra-mta which provides mail-transport-agent is to be removed.
   logwatch depends on postfix | mail-transport-agent; however:
    Package postfix is not installed.
    Package mail-transport-agent is not installed.
    Package zimbra-mta which provides mail-transport-agent is to be removed.

  
  apt-cache kind of functions with postfix as the rdepends:

  root at zre-ldap004:/home/build# apt-cache rdepends --installed postfix
  postfix
  Reverse Depends:
   |logwatch
    libsasl2-2
   |cron

  
  so we pick up logwatch in that case.

  However, we *still* fail to find mailutils:

  root at zre-ldap004:/home/build# apt-cache rdepends --installed default-mta
  <default-mta>

  
  So the rdepends flag for apt-cache seems to be completely broken for virtual packages.

  root at zre-ldap004:/home/build# apt-cache showpkg zimbra-mta
  Package: zimbra-mta
  Versions:
  8.7.0.GA.1655.UBUNTU14.64 (/var/lib/dpkg/status)
   Description Language:
                   File: /var/lib/dpkg/status
                    MD5: b25f6328eb0ffec1cb7bcd41cb0ddc9b

  
  Reverse Depends:
  Dependencies:
  8.7.0.GA.1655.UBUNTU14.64 - zimbra-core (0 (null)) zimbra-mta-components (0 (null)) mail-transport-agent (0 (null)) mail-transport-agent:i386 (0 (null)) mail-transport-agent (0 (null)) mail-transport-agent:i386 (0 (null))
  Provides:
  8.7.0.GA.1655.UBUNTU14.64 - mail-transport-agent
  Reverse Provides:

  
  root at zre-ldap004:/home/build# apt-cache showpkg logwatch
  Package: logwatch
  Versions:
  7.4.0+svn20130529rev144-1ubuntu1 (/var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_trusty_main_binary-amd64_Packages) (/var/lib/dpkg/status)
   Description Language:
                   File: /var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_trusty_main_binary-amd64_Packages
                    MD5: ece539a8a87c5f861d7f0b865e42a03c
   Description Language: en
                   File: /var/lib/apt/lists/us.archive.ubuntu.com_ubuntu_dists_trusty_main_i18n_Translation-en
                    MD5: ece539a8a87c5f861d7f0b865e42a03c

  
  Reverse Depends:
  Dependencies:
  7.4.0+svn20130529rev144-1ubuntu1 - perl (0 (null)) postfix (16 (null)) mail-transport-agent (0 (null)) fortune-mod (0 (null)) libdate-manip-perl (0 (null))
  Provides:
  7.4.0+svn20130529rev144-1ubuntu1 -
  Reverse Provides:

  
  root at zre-ldap004:/home/build# cat /etc/lsb-release
  DISTRIB_ID=Ubuntu
  DISTRIB_RELEASE=14.04
  DISTRIB_CODENAME=trusty
  DISTRIB_DESCRIPTION="Ubuntu 14.04.4 LTS"

  root at zre-ldap004:/home/build# apt-cache policy apt
  apt:
    Installed: 1.0.1ubuntu2.14
    Candidate: 1.0.1ubuntu2.14
    Version table:
   *** 1.0.1ubuntu2.14 0
          500 http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
          100 /var/lib/dpkg/status
       1.0.1ubuntu2.13 0
          500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
       1.0.1ubuntu2 0
          500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

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