ksh -n: Fix spurious warning for --(no)backslashctrl (#932)

src/cmd/ksh93/sh/parse.c: simple():
- During noexec, use strmatch() to more precisely identify obsolete
  options passed to set(1). This fixes a bug where 'ksh -n' would
  falsely flag --nobackslashctrl as obsolete, and also allows for
  the detection of other obsolescent options besides just '-k'.
  Additionally, do this in a loop to check all of the options
  passed to set (rather than just the first option).
- Also check for and warn against the obsolete 'alias -x' (ksh93
  has never supported exported aliases).

src/cmd/ksh93/{data/builtins.c,include/builtins.h,sh/shcomp.c}:
- More clearly document which options to set(1) are obsolete.
- Add SYSALIAS offset macro and use that instead of strcmp.
- Do not compile in usage information for arrowkeysearch or
  backslashctrl if the editor modes are not compiled in.

Author: JohnoKing

NEWS

@@ -2,6 +2,12 @@ This documents significant changes in the dev branch of ksh 93u+m.
 For full details, see the git log at: https://github.com/ksh93/ksh
 Uppercase BUG_* IDs are shell bug IDs as used by the Modernish shell library.
 
+2026-02-15:
+
+- Fixed a bug in 'ksh -n' that caused the shell to overlook many
+  obsolete options passed to set(1) and alias(1) and incorrectly
+  flag non-obsolete options as obsolete.
+
 2026-02-06:
 
 - Fixed a file descriptor leak introduced in 93u+ 2012-07-27 that occurred

src/cmd/ksh93/Mamfile

@@ -325,6 +325,7 @@ make install virtual
 	done
 
 	make sh/shcomp.c
+		prev include/builtins.h
 		prev include/terminal.h
 		prev include/shnodes.h
 		prev include/path.h

src/cmd/ksh93/data/builtins.c

@@ -78,10 +78,10 @@ const struct shtable3 shtab_builtins[] =
 	"source",	NV_BLTIN|BLT_ENV,		bltin(dot_cmd),
 	"return",	NV_BLTIN|BLT_ENV|BLT_SPC,	bltin(return),
 	"enum",		NV_BLTIN|BLT_ENV|BLT_DCL,	bltin(enum),
+	"alias",	NV_BLTIN|BLT_ENV,		bltin(alias),
 /*
  * Builtins without offset macros in include/builtins.h follow.
  */
-	"alias",	NV_BLTIN|BLT_ENV,		bltin(alias),
 	"hash",		NV_BLTIN|BLT_ENV,		bltin(alias),
 	"eval",		NV_BLTIN|BLT_ENV|BLT_SPC|BLT_EXIT,bltin(eval),
 	"exit",		NV_BLTIN|BLT_ENV|BLT_SPC,	bltin(return),
@@ -172,7 +172,7 @@ const char sh_set[] =
 "}"
 "[f?Pathname expansion is disabled.]"
 "[h?Obsolete; no effect.]"
-"[k?All arguments of the form \aname\a\b=\b\avalue\a "
+"[k?Obsolete. All arguments of the form \aname\a\b=\b\avalue\a "
 	"are removed and placed in the variable assignment list for "
 	"the command. Ordinarily, variable assignments must precede "
 	"command arguments.]"
@@ -196,12 +196,14 @@ const char sh_set[] =
 	"It must resolve to one of the following:]"
 	"{"
 		"[+allexport?Equivalent to \b-a\b.]"
+#if SHOPT_ESH || SHOPT_VSH
 		"[+arrowkeysearch?The up and down arrow keys will do a "
 		"reverse search based on the current line.]"
 		"[+backslashctrl?The backslash character \b\\\b escapes the "
 			"next control character in the \bemacs\b built-in "
 			"editor and the next \aerase\a or \akill\a character "
 			"in the \bvi\b built-in editor. On by default.]"
+#endif
 		"[+bgnice?Runs background jobs at lower priorities.]"
 #if SHOPT_BRACEPAT
 		"[+braceexpand?Equivalent to \b-B\b.] "
@@ -249,7 +251,7 @@ const char sh_set[] =
 		"[+ignoreeof?Prevents an interactive shell from exiting on "
 			"reading an end-of-file.]"
 #endif
-		"[+keyword?Equivalent to \b-k\b.]"
+		"[+keyword?Obsolete; equivalent to \b-k\b.]"
 		"[+letoctal?The \blet\b builtin recognizes octal constants "
 			"with leading 0.]"
 		"[+markdirs?A trailing \b/\b is appended to directories "
@@ -272,7 +274,7 @@ const char sh_set[] =
 		"[+privileged?Equivalent to \b-p\b.]"
 		"[+showme?Simple commands preceded by a \b;\b will be traced "
 			"as if \b-x\b were enabled but not executed.]"
-		"[+trackall?Equivalent to \b-h\b.]"
+		"[+trackall?Obsolete; equivalent to \b-h\b (no effect).]"
 		"[+unset?Opposite of \b-u\b.]"
 		"[+verbose?Equivalent to \b-v\b.]"
 #if SHOPT_VSH
@@ -1663,7 +1665,7 @@ const char sh_optksh[] =
 "[+SEE ALSO?\bset\b(1), \bbuiltin\b(1)]"
 ;
 const char sh_optset[] =
-"+[-1c?\n@(#)$Id: set (ksh 93u+m) 2023-05-18 $\n]"
+"+[-1c?\n@(#)$Id: set (ksh 93u+m) 2026-02-10 $\n]"
 "[--catalog?" SH_DICT "]"
 "[+NAME?set - set/unset options and positional parameters]"
 "[+DESCRIPTION?\bset\b sets or unsets options and positional parameters. "

src/cmd/ksh93/data/lexstates.c

@@ -749,8 +749,10 @@ const char e_lexobsolete1[]	= "line %d: `...` obsolete, use $(...)";
 const char e_lexobsolete2[]	= "line %d: -a obsolete, use -e";
 const char e_lexobsolete3[]	= "line %d: '=' obsolete, use '=='";
 const char e_lexobsolete4[]	= "line %d: [[ ... %s ... ]] obsolete, use ((... %s ...))";
-const char e_lexobsolete5[]	= "line %d: set %s obsolete";
+const char e_lexobsolete5[]	= "line %d: 'set %s' obsolete";
 const char e_lexobsolete6[]	= "line %d: `{' instead of `in' is obsolete";
+const char e_lexobsolete7[]	= "line %d: 'set %s %s' is obsolete";
+const char e_lexobsolete8[]	= "line %d: 'alias %s' is obsolete";
 const char e_lexusebrace[]	= "line %d: use braces to avoid ambiguities with $id[...]";
 const char e_lexescape[]	= "line %d: escape %c to avoid ambiguities";
 const char e_lexquote[]		= "line %d: quote %c to avoid ambiguities";

src/cmd/ksh93/include/builtins.h

@@ -2,7 +2,7 @@
 *                                                                      *
 *               This software is part of the ast package               *
 *          Copyright (c) 1982-2012 AT&T Intellectual Property          *
-*          Copyright (c) 2020-2025 Contributors to ksh 93u+m           *
+*          Copyright (c) 2020-2026 Contributors to ksh 93u+m           *
 *                      and is licensed under the                       *
 *                 Eclipse Public License, Version 2.0                  *
 *                                                                      *
@@ -55,6 +55,7 @@
 #define SYSSOURCE	(sh.bltin_cmds+21)	/* source */
 #define SYSRETURN	(sh.bltin_cmds+22)	/* return */
 #define SYSENUM		(sh.bltin_cmds+23)	/* enum */
+#define SYSALIAS	(sh.bltin_cmds+24)	/* alias */
 
 /* entry point for shell special builtins */
 

src/cmd/ksh93/include/lexstates.h

@@ -147,6 +147,8 @@ extern const char e_lexobsolete3[];
 extern const char e_lexobsolete4[];
 extern const char e_lexobsolete5[];
 extern const char e_lexobsolete6[];
+extern const char e_lexobsolete7[];
+extern const char e_lexobsolete8[];
 extern const char e_lexusebrace[];
 extern const char e_lexescape[];
 extern const char e_lexquote[];

src/cmd/ksh93/include/version.h

@@ -18,7 +18,7 @@
 #include <ast_release.h>
 #include "git.h"
 
-#define SH_RELEASE_DATE	"2026-02-09"	/* must be in this format for $((.sh.version)) */
+#define SH_RELEASE_DATE	"2026-02-15"	/* 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/parse.c

@@ -2,7 +2,7 @@
 *                                                                      *
 *               This software is part of the ast package               *
 *          Copyright (c) 1982-2012 AT&T Intellectual Property          *
-*          Copyright (c) 2020-2025 Contributors to ksh 93u+m           *
+*          Copyright (c) 2020-2026 Contributors to ksh 93u+m           *
 *                      and is licensed under the                       *
 *                 Eclipse Public License, Version 2.0                  *
 *                                                                      *
@@ -1415,7 +1415,7 @@ static struct argnod *process_sub(Lex_t *lexp,int tok)
 static Shnode_t *simple(Lex_t *lexp,int flag, struct ionod *io)
 {
 	struct comnod	*t;
-	struct argnod	*argp;
+	struct argnod	*argp, *ap;
 	int		tok;
 	struct argnod	**argtail;
 	struct argnod	**settail;
@@ -1458,7 +1458,7 @@ static Shnode_t *simple(Lex_t *lexp,int flag, struct ionod *io)
 			lexp->assignok = (flag&SH_ASSIGN)?SH_ASSIGN:1;
 			if(assignment)
 			{
-				struct argnod *ap=argp;
+				ap=argp;
 				if(assignment==1)
 				{
 					stkseek(sh.stk,ARGVAL);
@@ -1536,7 +1536,6 @@ static Shnode_t *simple(Lex_t *lexp,int flag, struct ionod *io)
 					type = NV_COMVAR;
 				else if((Namval_t*)t->comnamp >= SYSTYPESET && (Namval_t*)t->comnamp <= SYSTYPESET_END)
 				{
-					struct argnod  *ap;
 					for(ap = t->comarg.ap->argnxt.ap; ap; ap = ap->argnxt.ap)
 					{
 						if(*ap->argval!='-')
@@ -1624,11 +1623,30 @@ static Shnode_t *simple(Lex_t *lexp,int flag, struct ionod *io)
 		}
 	}
 #endif /* SHOPT_KIA */
-	/* noexec: warn about set - and set -k */
-	if(sh_isoption(SH_NOEXEC) && t->comnamp && (argp = t->comarg.ap->argnxt.ap)
-	&& (Namval_t*)t->comnamp==SYSSET && ((tok = *argp->argval)=='-' || tok=='+')
-	&& (argp->argval[1]==0 || strchr(argp->argval,'k')))
-		errormsg(SH_DICT,ERROR_warn(0),e_lexobsolete5,sh.inlineno-(lexp->token=='\n'),argp->argval);
+	/* noexec: warn about obsolescent options passed to set and alias */
+	if(sh_isoption(SH_NOEXEC) && t->comnamp)
+	{
+		int lineno = sh.inlineno - (lexp->token == NL);
+		if((Namval_t*)t->comnamp==SYSSET)
+		{
+			char *prev_argval = NULL;
+			for(ap = t->comarg.ap->argnxt.ap; ap; ap = ap->argnxt.ap)
+			{
+				if(strmatch(ap->argval,"(*eyword|*og|*rackall|*iraw)|([+-][^-]*[hkt]*)|([+-][hkt]*)|([+-])"))
+				{
+					if(strmatch(prev_argval,"[+-]o"))
+						errormsg(SH_DICT,ERROR_warn(0),e_lexobsolete7,lineno,prev_argval,ap->argval);
+					else
+						errormsg(SH_DICT,ERROR_warn(0),e_lexobsolete5,lineno,ap->argval);
+				}
+				prev_argval = ap->argval;
+			}
+		}
+		else if((Namval_t*)t->comnamp==SYSALIAS)
+			for(ap = t->comarg.ap->argnxt.ap; ap; ap = ap->argnxt.ap)
+				if(strmatch(ap->argval, "-*x*"))
+					errormsg(SH_DICT,ERROR_warn(0),e_lexobsolete8,lineno,ap->argval);
+	}
 	/* expand argument list if possible */
 	if(argno>0 && !(flag&(SH_ARRAY|NV_APPEND)))
 		t->comarg.ap = qscan(t,argno);

src/cmd/ksh93/sh/shcomp.c

@@ -2,7 +2,7 @@
 *                                                                      *
 *               This software is part of the ast package               *
 *          Copyright (c) 1982-2011 AT&T Intellectual Property          *
-*          Copyright (c) 2020-2025 Contributors to ksh 93u+m           *
+*          Copyright (c) 2020-2026 Contributors to ksh 93u+m           *
 *                      and is licensed under the                       *
 *                 Eclipse Public License, Version 2.0                  *
 *                                                                      *
@@ -73,6 +73,7 @@ static const char usage[] =
 #include	"shnodes.h"
 #include	"sys/stat.h"
 #include	"terminal.h"
+#include	"builtins.h"
 
 #define CNTL(x)	((x)&037)
 static const char header[6] = { CNTL('k'),CNTL('s'),CNTL('h'),0,SHCOMP_HDR_VERSION,0 };
@@ -172,7 +173,7 @@ int main(int argc, char *argv[])
 		stkset(sh.stk,NULL,0);
 		if(t = (Shnode_t*)sh_parse(in,0))
 		{
-			if((t->tre.tretyp&(COMMSK|COMSCAN))==0 && t->com.comnamp && strcmp(nv_name((Namval_t*)t->com.comnamp),"alias")==0)
+			if((t->tre.tretyp&(COMMSK|COMSCAN))==0 && t->com.comnamp && (Namval_t*)t->com.comnamp==SYSALIAS)
 				/* Create aliases found in the script to prevent syntax errors */
 				sh_exec(t,0);
 			if(!dflag && sh_tdump(out,t) < 0)

src/cmd/ksh93/tests/options.sh

@@ -2,7 +2,7 @@
 #                                                                      #
 #               This software is part of the ast package               #
 #          Copyright (c) 1982-2012 AT&T Intellectual Property          #
-#          Copyright (c) 2020-2025 Contributors to ksh 93u+m           #
+#          Copyright (c) 2020-2026 Contributors to ksh 93u+m           #
 #                      and is licensed under the                       #
 #                 Eclipse Public License, Version 2.0                  #
 #                                                                      #
@@ -679,6 +679,41 @@ exp=$'+ true\n+ 1> /dev/null 2>& 1 3>& 1 4>& 3'
 got=$(set --pipefail; "$SHELL" -c 'kill -s PIPE $$' | true; echo $?)
 exp=$(( ${ kill -l PIPE; } + 256 ))
 [[ $got == "$exp" ]] || err_exit "status of signalled process in pipe with pipefail (expected $exp, got $got)"
+unset exp got
+
+# ======
+# ksh -n should flag all obsolete set(1) and alias(1) arguments
+if((SHOPT_VSH)); then
+script=$tmp/setscr.$RANDOM.ksh
+echo 'set -k -n +t	# Obsolete
+set --keyword		# Obsolete
+set --log		# Obsolete
+set -tn			# Obsolete
+set --nobackslashctrl	# Current
+set --trackall		# Obsolete
+set -be			# Current
+set --errexit --nolog	# Obsolete
+set -o keyword		# Obsolete
+set -o backslashctrl -v # Current
+set -o backslashctrl -h # Obsolete
+set -o viraw -m		# Obsolete
+set +o nokeyword +h	# Obsolete
+alias -x foo		# Obsolete
+alias -pt -tx		# Obsolete
+alias -p		# Current
+alias -t -pxt -xp	# Obsolete
+set -eku		# Obsolete
+set -ebku		# Obsolete
+set -o posix -emu	# Current
+set -			# Obsolete
+set +			# Obsolete
+set --			# Current' > "$script"
+exp=20
+got=($(wc -l <(set +x; "$SHELL" -n "$script" 2>&1)))
+[[ ${got[0]} -eq $exp ]] || err_exit "ksh -n is not flagging all instances of obsolete options to set and alias" \
+	"(expected $exp warnings, got ${got[0]} warnings)"
+unset script exp got
+fi
 
 # ======
 exit $((Errors<125?Errors:125))