Bug#895953: lintian: check that shlibs-version >= higher-version-symbols-file

[Emilio Pozuelo Monfort <pochu@debian.org>]

Package: lintian
Version: 2.5.82
Severity: wishlist

Hi,

It would be good to check that the version in a shlibs file doesn't
fall behind wrt the version in the .symbols file. E.g. one may have
a call to
	dh_makeshlibs -plibfoo1 -V"1.0" -- -c4

updated when the 1.0 version got packaged, as it may have introduced
new symbols. Then, on an update to 1.1, new symbols may have been
introduced, and the maintainer would have updated the .symbols file
with the new symbols at version 1.1, but may have forgotten to update
the version in the dh_makeshlibs -V option (which ends up in the shlibs
file).

This is specially important for udebs, as they use the shlibs even
when .symbols files exist.

Another option would be for dh_makeshlibs to automatically use a
higher version if there's a higher one in the .symbols file. Not
sure we want to go that way though.

tl;dr: check if the shlibs CONTROL file in a .deb has a high enough
version as compared to MAX(versions in symbols CONTROL file)

Cheers,
Emilio