Subject: bug#44905: 27.1; Packages that customize xref-show-xrefs-function can break Dired's dired-do-find-regexp-and-replace

From: Daniel Martín <[email-masked]>
Date: Sun, 29 Nov 2020 13:57:14 +0100

Dmitry Gutov <[email-masked]> writes:
>
> While this change in the Right Thing(tm), I have to question the
> wisdom of setting xref-show-xrefs-function to an Ivy or Helm-based
> function, though. Those UIs serve to help you choose one item, whereas
> commands like dired-do-find-regexp and project-find-regexp show the
> user a list of matches, to interact with (usually) several of them.

I agree with you, Ivy/Helm may not be the best UX for Xref, but this
particular problem can still happen even if the user returns a buffer
that represents the Xref data in a different way.  I think that
xref-query-replace-in-results assumes certain invariants from the
original *xref* buffer that are not documented.

>
> diff --git a/lisp/dired-aux.el b/lisp/dired-aux.el
> index 94a2bbf1f3..4caafc8df6 100644
> --- a/lisp/dired-aux.el
> +++ b/lisp/dired-aux.el
> @@ -3140,7 +3140,10 @@ dired-do-find-regexp-and-replace
>            (query-replace-read-args
>             "Query replace regexp in marked files" t t)))
>       (list (nth 0 common) (nth 1 common))))
> -  (with-current-buffer (dired-do-find-regexp from)
> +  (defvar xref-show-xrefs-function)
> +  (with-current-buffer
> +      (let ((xref-show-xrefs-function 'xref--show-xref-buffer))
> +        (dired-do-find-regexp from))
>      (xref-query-replace-in-results from to)))
>
>  (defun dired-nondirectory-p (file)

LGTM, thanks.