[Emacs-diffs] master a773a64: Allow regexp-quote to return its argument

[Mattias Engdegård]

branch: master
commit a773a6474897356cd78aeea092d2c1a51ede23f9
Author: Mattias Engdegård <address@hidden>
Commit: Mattias Engdegård <address@hidden>

    Allow regexp-quote to return its argument
    
    * src/search.c (Fregexp_quote): Only allocate a new string if needed.
    * doc/lispref/searching.texi (Regexp Functions):
    * etc/NEWS (Incompatible Lisp Changes): Document.
---
 doc/lispref/searching.texi |  3 +++
 etc/NEWS                   |  4 ++++
 src/search.c               | 10 ++++++----
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/doc/lispref/searching.texi b/doc/lispref/searching.texi
index 1286b63..65f56b4 100644
--- a/doc/lispref/searching.texi
+++ b/doc/lispref/searching.texi
@@ -1562,6 +1562,9 @@ whitespace:
  (concat "\\s-" (regexp-quote string) "\\s-"))
 @end group
 @end example
+
+The returned string may be @var{string} itself if it does not contain
+any special characters.
 @end defun
 
 @cindex optimize regexp
diff --git a/etc/NEWS b/etc/NEWS
index 3072d40..96b2cb1 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2157,6 +2157,10 @@ valid event type.
 be specified in image specs representing the entire bitmap as a single
 bool vector.
 
++++
+** 'regexp-quote' may return its argument string.
+If the argument needs no quoting, it can be returned instead of a copy.
+
 
 * Lisp Changes in Emacs 27.1
 
diff --git a/src/search.c b/src/search.c
index 1e57d2e..9d95dcb 100644
--- a/src/search.c
+++ b/src/search.c
@@ -3138,10 +3138,12 @@ DEFUN ("regexp-quote", Fregexp_quote, Sregexp_quote, 1, 
1, 0,
     }
 
   Lisp_Object result
-    = make_specified_string (temp,
-                            SCHARS (string) + backslashes_added,
-                            out - temp,
-                            STRING_MULTIBYTE (string));
+    = (backslashes_added > 0
+       ? make_specified_string (temp,
+                                SCHARS (string) + backslashes_added,
+                                out - temp,
+                                STRING_MULTIBYTE (string))
+       : string);
   SAFE_FREE ();
   return result;
 }