Fix copying text properties by 'format'

* src/editfns.c (styled_format): Fix copying text properties from
the format specification to the produced string representation.
(Bug#23730)
(Fformat) Doc fix.

* doc/lispref/strings.texi (Formatting Strings): Document that
text properties from the format specifiers are also copied to the
produced string.

1 files changed, 7 insertions, 4 deletions

diff --git a/src/editfns.c b/src/editfns.c
index f29fc510a21..a6d13545711 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -3883,6 +3883,9 @@ precision specifier says how many decimal places to show; if zero, the
 decimal point itself is omitted.  For %s and %S, the precision
 specifier truncates the string to the given width.
 
+Text properties, if any, are copied from the format-string to the
+produced text.
+
 usage: (format STRING &rest OBJECTS)  */)
   (ptrdiff_t nargs, Lisp_Object *args)
 {
@@ -4170,6 +4173,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
               convbytes += padding;
               if (convbytes <= buf + bufsize - p)
                 {
+                  info[n].start = nchars;
                   if (! minus_flag)
                     {
                       memset (p, ' ', padding);
@@ -4188,9 +4192,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
                                   nbytes,
                                   STRING_MULTIBYTE (args[n]), multibyte);
 
-                  info[n].start = nchars;
                   nchars += nchars_string;
-                  info[n].end = nchars;
 
                   if (minus_flag)
                     {
@@ -4198,6 +4200,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
                       p += padding;
                       nchars += padding;
                     }
+                  info[n].end = nchars;
 
                   /* If this argument has text properties, record where
                      in the result string it appears.  */
@@ -4415,6 +4418,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
                         exponent_bytes = src + sprintf_bytes - e;
                     }
 
+                  info[n].start = nchars;
                   if (! minus_flag)
                     {
                       memset (p, ' ', padding);
@@ -4437,9 +4441,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
                   memcpy (p, src, exponent_bytes);
                   p += exponent_bytes;
 
-                  info[n].start = nchars;
                   nchars += leading_zeros + sprintf_bytes + trailing_zeros;
-                  info[n].end = nchars;
 
                   if (minus_flag)
                     {
@@ -4447,6 +4449,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
                       p += padding;
                       nchars += padding;
                     }
+                  info[n].end = nchars;
 
                   continue;
                 }