Fix KEYBD trap for multibyte characters (re: 4886463)

The KEYBD trap should now be fully functional for UTF-8 and other
multibyte locales. Thanks to Johnothan King for finding this fix!

Analysis: The KEYBD trap code processes character code points
stored in e_lbuf by ed_read(). But shell variables store bytes, not
characters. So, in UTF-8 locales for example, the Unicode code
points need to be converted to multibyte UTF-8 encoding. This is
needed to calculate the length of each encoded character in bytes
(which fixes the corruption issue) and for keytrap() to store its
UTF-8 representation in ${.sh.edchar}.

src/cmd/ksh93/edit/edit.c: ed_getchar():
- Remove the workaround from the referenced commit.
- Use mbconv to convert innput codepoints to bytes before adding
  them to inbuff, a char array that is passed on to keytrap().

Related:  https://bugzilla.redhat.com/show_bug.cgi?id=1503922
Related:  att#197
Related:  #307
Resolves: #460
Co-authored-by: Johnothan King <[email protected]>

NEWS

@@ -2,6 +2,12 @@ This documents significant changes in the 1.0 branch of ksh 93u+m.
 For full details, see the git log at: https://github.com/ksh93/ksh/tree/1.0
 Uppercase BUG_* IDs are shell bug IDs as used by the Modernish shell library.
 
+2024-12-30:
+
+- The KEYBD trap should now be fully functional for multibyte characters
+  (for example, non-Latin characters in UTF-8 locales). This fixes a bug
+  inherited from AT&T and worked around on 2022-02-12.
+
 2024-12-25:
 
 - The dirname path-bound built-in now accepts multiple operands.

src/cmd/ksh93/edit/edit.c

@@ -836,14 +836,11 @@ int ed_getchar(Edit_t *ep,int mode)
 		{
 			if(mode<=0 && -c == ep->e_intr)
 				killpg(getpgrp(),SIGINT);
-			if(mode<=0 && sh.st.trap[SH_KEYTRAP]
-			/* workaround for <https://github.com/ksh93/ksh/issues/307>:
-			 * do not trigger KEYBD for non-ASCII in multibyte locale */
-			&& (!mbwide() || c > -128))
+			if(mode<=0 && sh.st.trap[SH_KEYTRAP])
 			{
 				ep->e_keytrap = 1;
-				n=1;
-				if((readin[0]= -c) == ESC)
+				n = mbconv(readin, -c);
+				if(n==1 && readin[0]==ESC)
 				{
 					while(1)
 					{

src/cmd/ksh93/include/version.h

@@ -18,7 +18,7 @@
 #include <ast_release.h>
 #include "git.h"
 
-#define SH_RELEASE_DATE	"2024-12-25"	/* must be in this format for $((.sh.version)) */
+#define SH_RELEASE_DATE	"2024-12-30"	/* must be in this format for $((.sh.version)) */
 /*
  * This comment keeps SH_RELEASE_DATE a few lines away from SH_RELEASE_SVER to avoid
  * merge conflicts when cherry-picking dev branch commits onto a release branch.

src/cmd/ksh93/sh.1

@@ -9513,10 +9513,6 @@ Thus, a trap on
 .B CHLD
 won't be executed until the foreground job terminates.
 .PP
-In locales that use a multibyte character set such as UTF-8, the
-.B KEYBD
-trap is only triggered for ASCII characters (1-127).
-.PP
 It is a good idea to leave a space after the comma operator in
 arithmetic expressions to prevent the comma from being interpreted
 as the decimal point character in certain locales.