Bug#909696: lintian: debian-rules-should-not-use-custom-compression-settings overzealously also reports -Zgzip

[Axel Beckert <abe@debian.org>]

Package: lintian
Version: 2.5.106

Hi,

according to the bugreport https://bugs.debian.org/829100 this tag was
primarily meant to catch too high xz compression settings. Also the
lintian long description seems to be targetted towards that case.

But this tag is also emitted on the rather conservative "-Zgzip" option
which is not that uncommon if you want to keep a package being able to
be installed on Debian Wheezy ELTS or Ubuntu 12.04 ESM (both are still
supported to some degree and have dpkg 1.16.x. And at least dpkg in
Wheezy has no xz support).

So IMHO this tag should not be emitted with legacy compression formats
like gzip or bzip2 (at least not with those which were default in the
past), just with too high (but not too low) xz compression settings or
more exotic (never having been default, like IIRC lzma) compression
formats.

I though see that explicitly using legacy compression formats
(especially bzip2 comes to my mind) may no more be supported in dpkg in
some future release, so it might be good to warn about that, too. But
that's by far less severe that too heavy xz compression settings.

So maybe this should be split up into two tags:

* too exotic/strong settings (warning level; current long desc.)
* conservative, maybe not future-proof settings which once were default
  (pedantic level; new long desc.)

-- System Information:
Debian Release: buster/sid
  APT prefers unstable
  APT policy: (990, 'unstable'), (600, 'testing'), (500, 'unstable-debug'), (500, 'buildd-unstable'), (110, 'experimental'), (1, 'experimental-debug'), (1, 'buildd-experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.17.0-1-amd64 (SMP w/8 CPU cores)
Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE=C.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)
LSM: AppArmor: enabled

Versions of packages lintian depends on:
ii  binutils                       2.31.1-6
ii  bzip2                          1.0.6-9
ii  diffstat                       1.61-1+b1
ii  dpkg                           1.19.1
ii  file                           1:5.34-2
ii  gettext                        0.19.8.1-7
ii  intltool-debian                0.35.0+20060710.4
ii  libapt-pkg-perl                0.1.34
ii  libarchive-zip-perl            1.64-1
ii  libcgi-pm-perl                 4.40-1
ii  libclass-accessor-perl         0.51-1
ii  libclone-perl                  0.39-1
ii  libdigest-sha-perl             6.02-1
ii  libdpkg-perl                   1.19.1
ii  libemail-valid-perl            1.202-1
ii  libfile-basedir-perl           0.08-1
ii  libipc-run-perl                20180523.0-1
ii  liblist-moreutils-perl         0.416-1+b3
ii  libparse-debianchangelog-perl  1.2.0-12
ii  libtext-levenshtein-perl       0.13-1
ii  libtimedate-perl               2.3000-2
ii  liburi-perl                    1.74-1
ii  libxml-simple-perl             2.25-1
ii  libyaml-libyaml-perl           0.74+repack-1
ii  man-db                         2.8.4-2
ii  patchutils                     0.3.4-2
ii  perl [libdigest-sha-perl]      5.26.2-7
ii  t1utils                        1.41-2
ii  xz-utils                       5.2.2-1.3

Versions of packages lintian recommends:
ii  libperlio-gzip-perl  0.19-1+b4

Versions of packages lintian suggests:
ii  binutils-multiarch     2.31.1-6
ii  dpkg-dev               1.19.1
ii  libhtml-parser-perl    3.72-3+b2
ii  libtext-template-perl  1.53-1

-- no debconf information