Subject: bug#54733: Match again in perform-replace

From: Juri Linkov <[email-masked]>
Date: Thu, 30 Jun 2022 20:52:10 +0300

Hi Dmitry,

> Thanks for working on this.
>
>> +				(replace-search search-string limit
>> +						regexp-flag delimited-flag
>> +						case-fold-search backward))
>
> I don't know this code too well, but perhaps SEARCH_STRING here should be
> anchored with something like "\\=" at the beginning?
>
> Otherwise the search can succeed here even if the next match is not
> here. Not sure how important that is, though.

Stefan confirmed that "\\=" is reliable.  Thanks for the suggestion.
Now everything is ready.  Please try the latest patch in bug#14013
together with the patch for xref.el below.  I've tested with your
test cases from bug#53758, and everything works well.

>> -         ;; Counteract the "do the next match now" hack in
>> -         ;; `perform-replace'.  And still, it'll report that those
>> -         ;; matches were "filtered out" at the end.
>> -         (isearch-filter-predicate
>> -          (lambda (beg end)
>> -            (and current-beg
>> -                 (>= beg current-beg)
>> -                 (<= end current-end))))
>
> Please note that we'll likely have to keep this code here for a number of
> Emacs releases. So the patch should be tested with both versions: with this
> code present and with it removed, to ensure present and future
> compatibility.

I guess this might need more conditionals like (>= emacs-major-version 29).

diff --git a/lisp/progmodes/xref.el b/lisp/progmodes/xref.el
index 0213ab3cc5..9b4adffa41 100644
--- a/lisp/progmodes/xref.el
+++ b/lisp/progmodes/xref.el
@@ -858,29 +858,9 @@ xref--outdated-p
 
 ;; FIXME: Write a nicer UI.
 (defun xref--query-replace-1 (from to iter)
-  (let* ((query-replace-lazy-highlight nil)
-         (continue t)
+  (let* ((continue t)
          did-it-once buf-pairs pairs
-         current-beg current-end
-         ;; Counteract the "do the next match now" hack in
-         ;; `perform-replace'.  And still, it'll report that those
-         ;; matches were "filtered out" at the end.
-         (isearch-filter-predicate
-          (lambda (beg end)
-            (and current-beg
-                 (>= beg current-beg)
-                 (<= end current-end))))
-         (replace-re-search-function
-          (lambda (from &optional _bound noerror)
-            (let (found pair)
-              (while (and (not found) pairs)
-                (setq pair (pop pairs)
-                      current-beg (car pair)
-                      current-end (cdr pair))
-                (goto-char current-beg)
-                (when (re-search-forward from current-end noerror)
-                  (setq found t)))
-              found))))
+         (region-extract-function (lambda (_) pairs)))
     (while (and continue (setq buf-pairs (funcall iter :next)))
       (if did-it-once
           ;; Reuse the same window for subsequent buffers.
@@ -889,8 +869,10 @@ xref--query-replace-1
          (pop-to-buffer (car buf-pairs)))
         (setq did-it-once t))
       (setq pairs (cdr buf-pairs))
+      (goto-char (point-min))
       (setq continue
-            (perform-replace from to t t nil nil multi-query-replace-map)))
+            (perform-replace from to t t nil nil multi-query-replace-map
+                             nil nil nil t)))
     (unless did-it-once (user-error "No suitable matches here"))
     (when (and continue (not buf-pairs))
       (message "All results processed"))))