From: Eli Zaretskii <eliz@gnu.org>
Date: Sun, 23 Aug 2020 18:23:45 +0000 (+0300)
Subject: Improve handling of coding-system mnemonic indicators
X-Git-Tag: emacs-28.0.90~6442
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=3a99f966dc2dc9fb3922340caa0016b305789977;p=emacs.git

Improve handling of coding-system mnemonic indicators

This fixes assertion violations when the mnemonic is
given as a string, and allows non-ASCII characters be
used as mode-line mnemonic of a coding-system.
* src/xdisp.c (decode_mode_spec_coding): Handle multibyte
characters as coding-system's mnemonic.
(display_mode_element): If decode_mode_spec returns a multibyte
string, display it as multibyte.
* src/coding.c (Fdefine_coding_system_internal)
(Fcoding_system_put): If :mnemonic is a string, use its first
character.  This avoids assertion violations if someone uses a
string as the mnemonic of a coding-system.
---

diff --git a/src/coding.c b/src/coding.c
index 51bd441de9d..221a9cad898 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -10895,7 +10895,10 @@ usage: (define-coding-system-internal ...)  */)
   ASET (attrs, coding_attr_base_name, name);
 
   Lisp_Object val = args[coding_arg_mnemonic];
-  if (! STRINGP (val))
+  /* decode_mode_spec_coding assumes the mnemonic is a single character.  */
+  if (STRINGP (val))
+    val = make_fixnum (STRING_CHAR (SDATA (val)));
+  else
     CHECK_CHARACTER (val);
   ASET (attrs, coding_attr_mnemonic, val);
 
@@ -11408,7 +11411,10 @@ DEFUN ("coding-system-put", Fcoding_system_put, Scoding_system_put,
   attrs = AREF (spec, 0);
   if (EQ (prop, QCmnemonic))
     {
-      if (! STRINGP (val))
+      /* decode_mode_spec_coding assumes the mnemonic is a single character.  */
+      if (STRINGP (val))
+	val = make_fixnum (STRING_CHAR (SDATA (val)));
+      else
 	CHECK_CHARACTER (val);
       ASET (attrs, coding_attr_mnemonic, val);
     }
diff --git a/src/xdisp.c b/src/xdisp.c
index e2ebbbdce72..9d2bec379dc 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -25637,6 +25637,11 @@ display_mode_element (struct it *it, int depth, int field_width, int precision,
 		    spec = decode_mode_spec (it->w, c, field, &string);
 		    eassert (NILP (string) || STRINGP (string));
 		    multibyte = !NILP (string) && STRING_MULTIBYTE (string);
+		    /* 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 (spec, nbytes) != nbytes)
+		      multibyte = true;
 
 		    switch (mode_line_target)
 		      {
@@ -26255,9 +26260,10 @@ decode_mode_spec_coding (Lisp_Object coding_system, char *buf, bool eol_flag)
       attrs = AREF (val, 0);
       eolvalue = AREF (val, 2);
 
-      *buf++ = multibyte
-	? XFIXNAT (CODING_ATTR_MNEMONIC (attrs))
-	: ' ';
+      if (multibyte)
+	buf += CHAR_STRING (XFIXNAT (CODING_ATTR_MNEMONIC (attrs)), buf);
+      else
+	*buf++ = ' ';
 
       if (eol_flag)
 	{