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

[Dmitry Gutov <dgutov@yandex.ru>]

On 03/11/2016 04:59 PM, Eli Zaretskii wrote:

> I said "etags", not "emacs".

I don't think this implies any considerable amount of work in etags 
either. I could be wrong, of course.

>> And allowing the output of qualified+unqualified, in etags, doesn't seem
>> like a huge job to me.
>
> For languages where qualified tags are already created, maybe.

And it is those languages where I think the users would be served better 
by a different behavior.

> (C-like languages might be not so easy, due to the state machines they
> use.)  But are we sure all languages do?

I'm sorry, all languages do what? Use state machines, and thus are "not 
so easy"?

>> We can perfectly well choose to support this feature only for a few
>> languages. It's better than nothing.
>
> I'm not sure "better than nothing" is good enough.

I'm not buying the argument that doing the right thing is somehow 
undesirable because we can't afford to do the perfect thing right now.

Especially since the transition path from "good" to "perfect" is natural 
in this case (just add support for more languages later). This way, you 
won't have to change the semantics of -Q in future releases, or invent 
another flag that behaves similarly to -Q, "but better", and deal with 
having to document that -Q is not actually recommended for use.

> Anyway, I don't really understand what we are arguing about.

I'm arguing that -Q should output both qualified and unqualified tags, 
so that the result is actually useful.

You seem to be arguing towards -Q preserving the previous behavior of 
the parser, _in certain languages_, no matter the usefulness of the 
resulting tag files.

Apparently, to support some consumers of tag files that do it in a 
fashion we can't predict, and might somehow be inconvenienced if the 
"qualified-only" output is not one of the options. Is that correct?

>> Here's the relevant excerpt from ctags's manpage:
>
> Thanks, but why do you think I don't have it installed?

You might, or you might not. It was easier to quote directly.

Does that excerpt not make sense to you?

>> Ultimately, it's your choice, of course.
>
> Volunteers are free to beat me to it, if they have an itch to scratch.

If you've made a deliberate choice, it doesn't seem like a patch from a 
volunteer that would make a different choice is likely to be accepted.