From: Mattias Engdegård <mattiase@acm.org>
Date: Fri, 7 Oct 2022 16:17:40 +0000 (+0200)
Subject: Improved format string error message (bug#58168)
X-Git-Tag: emacs-29.0.90~1616^2~689
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=71b3a37569ffa58f3640a742e31eade42cc26f98;p=emacs.git

Improved format string error message (bug#58168)

* src/editfns.c (styled_format): Better message when the conversion
char is non-ASCII from a unibyte format string.
---

diff --git a/src/editfns.c b/src/editfns.c
index c1414071c79..3f9618edb08 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -3551,10 +3551,15 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
 		      || float_conversion || conversion == 'i'
 		      || conversion == 'o' || conversion == 'x'
 		      || conversion == 'X'))
-	    error ("Invalid format operation %%%c",
-		   multibyte_format
-		   ? STRING_CHAR ((unsigned char *) format - 1)
-		   : *((unsigned char *) format - 1));
+	    {
+	      unsigned char *p = (unsigned char *) format - 1;
+	      if (multibyte_format)
+		error ("Invalid format operation %%%c", STRING_CHAR (p));
+	      else
+		error (*p <= 127 ? "Invalid format operation %%%c"
+		                 : "Invalid format operation char #o%03o",
+		       *p);
+	    }
 	  else if (! (FIXNUMP (arg) || ((BIGNUMP (arg) || FLOATP (arg))
 					&& conversion != 'c')))
 	    error ("Format specifier doesn't match argument type");