Bug#947915: release-notes: Suggest cleaning up leftover *.dpkg-old etc. config files

[Justin B Rye <justin.byam.rye@gmail.com>]

Karl O. Pinc wrote:
>>> +    files; <link linkend="configuration-changes">old versions</link>
>>> +    of configuration files, versions supplied by the package
>>> +    maintainers, etc.  Removing leftover files from previous upgrades,
>>> +    before performing another upgrade, can avoid confusion.  
>> 
>> The commas in this sentence seem subtly wrong.
> 
> I think the commas are right, as a parenthetical-ish without
> parenthesis, but the sentence structure is strange.  But
> I want the forgettable stuff in the middle and the important
> stuff on the ends of the sentence where the reader pays attention.

The trouble is, it isn't purely parenthetical; it's talking about
removing the leftover files under particular circumstances, so it's
rather like a defining relative clause (which doesn't take commas).
The competing misinterpretation is that you can avoid confusion by
removing these files and subsequently performing another upgrade
(that you otherwise wouldn't have performed).  Given that you're
proposing this text as pre-upgrade advice, but that it's also true for
any other time, we might as well just say

                      Removing files left over from previous upgrades
    can avoid confusion.

>> It might fit best in 4.7. "Preparing for the next release".
> 
> I like to leave the leftover files laying around for a while after
> upgrade just in case they shed light on some problem that I don't
> notice until later.  So I clean them up (or not, usually) before
> doing the next upgrade because I forget they exist.

It seems to me that users ought to do this within a few days of a
dist-upgrade while they remember the circumstances, not months or
years later.  But it's quite possible that it only seems that way to
me because of the habits I've got into thanks to my nagging cronjobs
(and associated system configuration backups).
 
[...]
> That makes the complete list: *.dpkg-new *.dpkg-old *.dpkg-save,
> *.dpkg-bak, *.pam-old, *.ucf-old, *.ucf-dist, *.merge-error

The ucf manpage also says that .ucf-new can occur as a symptom of an
interrupted run (like .dpkg-new); and in theory there's .dpkg-inst, so
maybe the search should use globs like "*.dpkg-*" and "*.ucf-*"
instead of trying to itemise them all.
-- 
JBR	with qualifications in linguistics, experience as a Debian
	sysadmin, and probably no clue about this particular package