emacs-29 3af27a4b815: Improve commentary in nsfns.m

[Po Lu]

branch: emacs-29
commit 3af27a4b815906c2ee38cbaf3a765289b3df061a
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Improve commentary in nsfns.m
    
    * src/nsfns.m (lispString): Avoid C++ comment and make the
    commentary actually relevant to the reason `make_string' is
    used.
---
 src/nsfns.m | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/nsfns.m b/src/nsfns.m
index 5ae2cc77bb2..fe565a423aa 100644
--- a/src/nsfns.m
+++ b/src/nsfns.m
@@ -3829,7 +3829,11 @@ all_nonzero_ascii (unsigned char *str, ptrdiff_t n)
 /* Make a Lisp string from an NSString.  */
 - (Lisp_Object)lispString
 {
-  // make_string behaves predictably and correctly with UTF-8 input.
+  /* `make_string' creates a string with a given length, instead of
+     searching for a trailing NULL byte to determine its end.  This is
+     important because this function is called to convert NSString
+     objects containing clipboard data, which can contain NUL bytes,
+     into Lisp strings.  (bug#64697) */
   return make_string ([self UTF8String],
                       [self lengthOfBytesUsingEncoding: NSUTF8StringEncoding]);
 }