Bug#797106: libperl5.22: Multi-Arch:same and binNMU changelogs

[Niko Tyni]

On Thu, Aug 27, 2015 at 11:05:30PM +0300, Niko Tyni wrote:
> Package: libperl5.22
> Version: 5.22.0-3
> Severity: important
> 
> Now that libperl5.22 is Multi-Arch:same, I believe we need to add special
> treatment to binNMU changelogs in the same vein as dh_installchangelogs
> does (see #708218): break architecture specific binary changelog entries
> out into separate files with an arch-qualified path.  Otherwise the
> binNMU'd packages will have different contents for an arch-indep
> file (/usr/share/doc/libperl5.22/changelog.Debian.gz), preventing
> co-installability.
> 
> See the thread at https://lists.debian.org/debian-dpkg/2012/07/msg00017.html
> for some background. I think the current hack in dh_installchangelogs
> is something of a temporary measure but we seem to be stuck with
> it for now.

I note that this will require changing the symlink
/usr/share/doc/libperl5.22 -> perl to a real separate directory. This
probably means we need a libperl5.22.preinst snippet that removes the
symlink on upgrades, as dpkg will not automatically replace a symlink
with a directory.

As for a patch, here's what I currently have:

----------------------------------------
#!/bin/sed -f
1,/^perl/ {
    1 { h;d }
    /^perl/ b
    H;d
}
$ {
    p;g;w /dev/stderr
d }
----------------------------------------

which will take the changelog on stdin, rip the first snippet and
output it on stderr (urgh, /dev/stderr is a GNUism) while leaving the
rest on stdout. The stdout part could probably be made to work with
in-place editing (-i).

This needs to be guarded to only run if binary-only=yes is on the
first line; didn't manage to fit that check in cleanly yet but
it could just as well be externalised.

Dominic raised the question of how much sense it makes to avoid
debhelper while we're using dpkg-parsechangelog, dpkg-buildflags, and
dpkg-shlibdeps which are /usr/bin/perl scripts. I'm not sure of
the answer but I'd rather discuss that separately (probably involving
the folks interested in Debian bootstrapping).
-- 
Niko Tyni   ntyni at debian.org