Fix copying text properties in 'format'

* src/editfns.c (styled_format): Fix accounting for text
properties that come from the format string.  (Bug#46317)

* test/src/editfns-tests.el (format-properties): Add new tests for
bug#46317.

1 files changed, 9 insertions, 1 deletions

diff --git a/src/editfns.c b/src/editfns.c
index e3285494c14..991f79abac7 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -3134,6 +3134,7 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
   char *format_start = SSDATA (args[0]);
   bool multibyte_format = STRING_MULTIBYTE (args[0]);
   ptrdiff_t formatlen = SBYTES (args[0]);
+  bool fmt_props = string_intervals (args[0]);
 
   /* Upper bound on number of format specs.  Each uses at least 2 chars.  */
   ptrdiff_t nspec_bound = SCHARS (args[0]) >> 1;
@@ -3406,13 +3407,20 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
               convbytes += padding;
               if (convbytes <= buf + bufsize - p)
                 {
+                  /* If the format spec has properties, we should account
+                     for the padding on the left in the info[] array.  */
+                  if (fmt_props)
+                    spec->start = nchars;
                   if (! minus_flag)
                     {
                       memset (p, ' ', padding);
                       p += padding;
                       nchars += padding;
                     }
-                  spec->start = nchars;
+                  /* If the properties will come from the argument, we
+                     don't extend them to the left due to padding.  */
+                  if (!fmt_props)
+                    spec->start = nchars;
 
                   if (p > buf
                       && multibyte