bug#22947: 25.0.92; xref-find-definitions fails for Perl & etags

[Eli Zaretskii]

> Cc: 22947@debbugs.gnu.org, rogers@modulargenetics.com
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Thu, 10 Mar 2016 17:50:37 +0200
> 
> On 03/10/2016 05:31 PM, Eli Zaretskii wrote:
> 
> > I decided to go the same way as with C-like languages: by default
> > produce unqualified tag names, unless -Q was specified.
> 
> Does calling etags '-Q' result in it producing *only* qualified names? 

Yes.

> That doesn't sound very useful.

Then users will not use that switch.  And note that before these
changes, etags would _always_ produce only qualified names.  So the -Q
switch provides a way to get the old behavior back.

> Do you expect the user to call 'etags' twice, with and without 'Q', and 
> append the outputs?

No, I think qualified names are almost never useful, given the way
TAGS tables are used in Emacs nowadays, so the -Q option is just a
kind of "fire escape" for use cases that I think should never happen.

If I'm wrong, then I'd like to see these use cases described, and we
should then rethink the whole issue of qualified tag names.