Bug#875305: Support for finding changelog.Debian.gz in perl-base

[Stuart Prescott]

I've rolled the patches attached to this bug into a merge request on salsa 
(with some minor updates as debfile.py itself has changed slightly since they 
were submitted).

https://salsa.debian.org/python-debian-team/python-debian/-/merge_requests/32

However, looking carefully at Policy §12.7, searching in /usr/share/doc/
$source/ would be the wrong thing to do. 

https://www.debian.org/doc/debian-policy/ch-docs.html#changelog-files-and-release-notes

Non-native packages are required to have /usr/share/doc/$package/
changelog.Debian.gz but the directory (or perhaps the file) can be a symlink; 
this is the case for perl-base that is cited in the bug report.

$ dpkg -S /usr/share/doc/perl-base
perl-base: /usr/share/doc/perl-base

$ ls -l /usr/share/doc/perl-base
lrwxrwxrwx 1 root root 4 Nov 10  2017 /usr/share/doc/perl-base -> perl/

$ dpkg -L perl-base | grep changelog
/usr/share/doc/perl/changelog.Debian.gz

and therefore "/usr/share/doc/perl-base/changelog.Debian.gz" exists, but only 
via a symlink.

The correct approach to finding the changelog is probably not to look at source 
package names, but to try to follow symlinks within the .deb

-- 
Stuart Prescott    http://www.nanonanonano.net/   stuart at nanonanonano.net
Debian Developer   http://www.debian.org/         stuart at debian.org
GPG fingerprint    90E2 D2C1 AD14 6A1B 7EBB 891D BBC1 7EBB 1396 F2F7