1

Does it make sense that apt-cache depends/rdepends are not always inverse to each other?

For instance, I have a host where apt-cache rdepends liblognorm1 lists these reverse dependencies: rsyslog liblognorm-dev, but apt-cache depends rsyslog does not include liblognorm1 (only liblognorm5) in its dependencies.

Is this a feature or a bug?

rookie099
  • 375
  • 3
  • 14

1 Answers1

0

Its a feature, and a necessary one, and your example is already a very good example.

A libraries older version might be depended on by an older version of a program. That programs current version will not depend on that older version of the library though. It may depend on a newer version of the library, or may have dropped/replaced that dependency.

The same program name can appear in the depends/rdepends output, but it can be referring to different versions. Use apt-cache showpkg, its output is a bit more clear about which version you are looking at and which other other packages are required or broken in which versions.

anx
  • 8,963
  • 5
  • 24
  • 48
  • The host had `liblognorm1`, `liblognorm5`, `rsyslog` (but not `liblognorm-dev`) installed. So I have concluded that it was safe to purge `liblognorm1`. – rookie099 Apr 04 '18 at 11:13
  • Agreed, except in the case of `liblognorm1` it was marked as manual and so `apt-get autoremove` did not pick it up. This seems to be the default setting on a plain-vanilla Debian Jessie installation. – rookie099 Apr 04 '18 at 12:07