Re: emacs-27 b46c75b: xref-matches-in-files: Big Tramp speed-up

[Stefan Monnier <monnier@iro.umontreal.ca>]

>>>> But allow me to state for the record once more that I'm puzzled by the
>>>> architectural choice we're working with here.
>>> I know that.  Tramp follows the generic file name handler approach, as
>>> described in (info "(elisp) Magic File Names") .
>> Could someone explain to me why `file-local-name` has to be so much slower
>> than `tramp-file-local-name`?
> Internally, `file-local-name' uses `file-remote-p'. The latter goes
> through the file name handler machinery, and `tramp-file-name-handler'
> eats time, according to Dmitry's measures. Usually not a problem, but
> remarkable when you apply it to some ten thousand files as in
> `xref-matches-in-files'.

[ I think this should be in a comment in the code ;-)  ]
Hmm... I guess this deserves a bug number and we should try and figure
out why it's so much slower to go through the file-handler machinery
(and whether we can do something about it other than provide ad-hoc
coarse-grained operations).


        Stefan