Re: xref-query-replace

[Dmitry Gutov]

On 01/09/2016 07:36 PM, Eli Zaretskii wrote:

> > I've posted a thread about it in November:
> > http://lists.gnu.org/archive/html/emacs-devel/2015-11/msg01465.html
>
> Thanks.  I've read it now, and it describes exactly what I did.  (Btw,
> why does it say to agree to ".*"? aren't other regexps supposed to
> work as well?)

Of course. These are just the steps to try it out quickly.

> Same result with this recipe:
>
>    emacs -Q
>    C-x C-f src/xdisp.c
>    M-.
>
> Press RET to confirm visiting the TAGS table in src/ (you should have
> one, of course).  You are now presented with a *xref* buffer that
> lists many matches for "Display".  (Should xref pick up symbols inside
> comments?)

etags does, apparently. Why else would xref show them?

In general, I'd say "yes", for "find references" or "find regexp" 
results. But not for "find definitions".

> In that buffer, type:
>
>    r RET xyzzy RET
>
> I get the same disappointing result.
>
> Stepping through xref-query-replace, it seems like xref-match-length
> always returns nil, so no matches are collected.  Which sounds about
> right, since I see no non-trivial definitions for xref-match-length,
> or maybe I'm blind.
>
> What am I doing wrong?

You're calling the "find definitions" command, not the "find references" 
or "find regexp".

xref-find-definitions returns a set of xrefs which we don't consider to 
be a set of "matches", currently. While the English language may frown 
on this, I think it's good that xref-query-replace doesn't work across 
the "find definitions" result, because if it did, you'd end up with a 
codebase in which the function's (definition is|definitions are) 
renamed, but all its usages keep referring to the old name.

Try starting with xref-find-references (bound to M-?).