Avoid aborts in display_mode_element

* src/xdisp.c (display_mode_element): Use parse_str_as_multibyte,
not multibyte_chars_in_text, to determine whether mode-line spec
shall be displayed as a multibyte or unibyte string.  We cannot
use multibyte_chars_in_text here because it aborts when it finds
raw bytes in the spec string.  (Bug#43409)

1 files changed, 4 insertions, 2 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 10ddb53dba2..615f0ca7cf8 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -25641,8 +25641,10 @@ display_mode_element (struct it *it, int depth, int field_width, int precision,
                     /* Non-ASCII characters in SPEC should cause mode-line
                        element be displayed as a multibyte string.  */
                     ptrdiff_t nbytes = strlen (spec);
-                    if (multibyte_chars_in_text ((const unsigned char *)spec,
-                                                 nbytes) != nbytes)
+                    ptrdiff_t nchars, mb_nbytes;
+                    parse_str_as_multibyte ((const unsigned char *)spec, nbytes,
+                                            &nchars, &mb_nbytes);
+                    if (!(nbytes == nchars || nbytes != mb_nbytes))
                       multibyte = true;
 
                     switch (mode_line_target)