bug#44861: 27.1; [PATCH] signal in `replace-regexp-in-string'

[Shigeru Fukaya <shigeru.fukaya@gmail.com>]

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`replace-regexp-in-string' sometimes signals an error when REGEXP
contains some bondary sequence.  Difference of searches between
against an original passed string and against an extracted substring
causes the incident.


(replace-regexp-in-string-simple "a\\B" "A" "a aaaa")
	error --> cons: Args out of range: 2, 3
    expected
	==> "a AAAa"

(replace-regexp-in-string "\\Ba" "A" "a aaaa")
	error --> cons: Args out of range: 3, 4
    expected
	==> "a aAAA"

--
Shigeru

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diff -u /usr/local/share/emacs/27.1/lisp/subr.el /usr/local/share/emacs/27.1/fix/subr-replaceRegexpInString.el
--- /usr/local/share/emacs/27.1/lisp/subr.el	2020-07-30 06:40:41.000000000 +0900
+++ /usr/local/share/emacs/27.1/fix/subr-replaceRegexpInString.el	2020-11-25 12:25:53.954515500 +0900
@@ -4426,9 +4426,9 @@
 	;; Generate a replacement for the matched substring.
 	;; Operate on only the substring to minimize string consing.
 	;; Set up match data for the substring for replacement;
-	;; presumably this is likely to be faster than munging the
-	;; match data directly in Lisp.
-	(string-match regexp (setq str (substring string mb me)))
+	;; reset match-data for substring by subtracting offsets.
+	(set-match-data (mapcar (lambda (n) (and n (- n mb))) (match-data)))
+	(setq str (substring string mb me))
 	(setq matches
 	      (cons (replace-match (if (stringp rep)
 				       rep

Diff finished.  Wed Nov 25 12:29:28 2020