Bug#834290: Warn about libraries with excessive priority?

[Josh Triplett <josh@joshtriplett.org>]

Package: lintian
Version: 2.5.46
Severity: wishlist

Now that Lintian no longer warns about dependencies on packages with
lower priorities, I think it would make sense for Lintian to warn about
library packages with excessively high priorities.  In general, a
library package should only get pulled in on a system because some other
package depends on it; no library package needs installation on a system
where nothing uses it.  Given that, I don't think it makes sense for any
library package to have a priority higher than "optional".

More concretely: I'd propose a warning on packages in section "libs"
with names matching "^lib.*" and not "-bin$", that have a priority of
"required", "important", or "standard".

I've reviewed every single package in Debian that would match that rule,
and I can confirm that it would produce zero false positives.

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.7.0-rc7-amd64 (SMP w/4 CPU cores)
Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages lintian depends on:
ii  binutils                          2.27-5
ii  bzip2                             1.0.6-8
ii  diffstat                          1.61-1
ii  file                              1:5.28-4
ii  gettext                           0.19.8.1-1
ii  hardening-includes                2.8+nmu2
ii  intltool-debian                   0.35.0+20060710.4
ii  libapt-pkg-perl                   0.1.29+b5
ii  libarchive-zip-perl               1.59-1
ii  libclass-accessor-perl            0.34-1
ii  libclone-perl                     0.38-2
ii  libdata-alias-perl                1.20-1+b1
ii  libdpkg-perl                      1.18.10
ii  libemail-valid-perl               1.200-1
ii  libfile-basedir-perl              0.07-1
ii  libipc-run-perl                   0.94-1
ii  liblist-moreutils-perl            0.416-1
ii  libparse-debianchangelog-perl     1.2.0-10
ii  libperl5.22 [libdigest-sha-perl]  5.22.2-3
ii  libtext-levenshtein-perl          0.13-1
ii  libtimedate-perl                  2.3000-2
ii  liburi-perl                       1.71-1
ii  libyaml-libyaml-perl              0.41-6+b1
ii  man-db                            2.7.5-1
ii  patchutils                        0.3.4-1
ii  perl                              5.22.2-3
ii  t1utils                           1.39-2
ii  xz-utils                          5.1.1alpha+20120614-2.1

Versions of packages lintian recommends:
ii  dpkg                                 1.18.10
pn  libperlio-gzip-perl                  <none>
ii  perl                                 5.22.2-3
ii  perl-modules-5.22 [libautodie-perl]  5.22.2-3

Versions of packages lintian suggests:
pn  binutils-multiarch     <none>
ii  dpkg-dev               1.18.10
ii  libhtml-parser-perl    3.72-2
pn  libtext-template-perl  <none>

-- no debconf information