Fix spurious export attribute when printing compound variables

Reproducer script:

    typeset -Ttyp1 typ1=(
            function get {
                    .sh.value="'Sample'";
            }
    )
    typ1 var11
    typeset -p .sh.type
    typeset -p .sh.type

Buggy output:

    namespace sh.type
    {
            typeset -r typ1='Sample'
    }
    namespace sh.type
    {
            typeset -x -r typ1='Sample'
    }

An -x (export) attribute is magically pulled out of a hat.

Analysis: The walk_tree() function in nvdisc.c repurposes (!) the
NV_EXPORT attribute as an instruction to turn *off* indenting when
pretty-printing the values of compound variables. The
print_namval() function in typeset.c, implementing 'typeset -p',
turns on NV_EXPORT for compound variables to inhibit indentation.
But it then does not bother to turn it off, which causes this bug.

src/cmd/ksh93/bltins/typeset.c: print_namval():
- When printing compound variables, only turn on NV_EXPORT
  temporarily.

Resolves: https://github.com/ksh93/ksh/issues/456

NEWS

@@ -3,6 +3,11 @@ For full details, see the git log at: https://github.com/ksh93/ksh/tree/1.0
 
 Any uppercase BUG_* names are modernish shell bug IDs.
 
+2022-06-07:
+
+- Fixed a bug in 'typeset' where compound variables could acquire a spurious
+  -x (export) attribute when printing their values, triggering other bugs.
+
 2022-06-05:
 
 - Fixed a bug where tab completion would spuriously execute a command

src/cmd/ksh93/bltins/typeset.c

@@ -1432,6 +1432,7 @@ static int print_namval(Sfio_t *file,register Namval_t *np,register int flag, st
 {
 	register char *cp;
 	int	indent=tp->indent, outname=0, isfun;
+	char	tempexport=0;
 	sh_sigcheck();
 	if(flag)
 		flag = '\n';
@@ -1523,9 +1524,19 @@ static int print_namval(Sfio_t *file,register Namval_t *np,register int flag, st
 		print_value(file,np,tp);
 		return(0);
 	}
-	if(nv_isvtree(np))
+	if(nv_isvtree(np) && !nv_isattr(np,NV_EXPORT))
+	{
+		/*
+		 * Compound variable. Repurpose NV_EXPORT to tell walk_tree() in nvdisc.c not
+		 * to indent the nv_getval() output. Also turn it back off, or bugs will happen.
+		 */
 		nv_onattr(np,NV_EXPORT);
-	if(cp=nv_getval(np))
+		tempexport++;
+	}
+	cp = nv_getval(np);
+	if(tempexport)
+		nv_offattr(np,NV_EXPORT);
+	if(cp)
 	{
 		if(indent)
 			sfnputc(file,'\t',indent);

src/cmd/ksh93/include/version.h

@@ -21,7 +21,7 @@
 
 #define SH_RELEASE_FORK	"93u+m"		/* only change if you develop a new ksh93 fork */
 #define SH_RELEASE_SVER	"1.0.0-beta.2"	/* semantic version number: https://semver.org */
-#define SH_RELEASE_DATE	"2022-06-05"	/* must be in this format for $((.sh.version)) */
+#define SH_RELEASE_DATE	"2022-06-07"	/* must be in this format for $((.sh.version)) */
 #define SH_RELEASE_CPYR	"(c) 2020-2022 Contributors to ksh " SH_RELEASE_FORK
 
 /* Scripts sometimes field-split ${.sh.version}, so don't change amount of whitespace. */

src/cmd/ksh93/tests/types.sh

@@ -734,5 +734,42 @@ exp=8
 [[ $got == $exp ]] || err_exit "short integer arrays in types isn't working correctly" \
 	"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
 
+# ======
+# Printing .sh.type should not crash or give variables a spurious -x attribute.
+# https://github.com/ksh93/ksh/issues/456
+
+got=$("$SHELL" -c 'typeset -p .sh.type
+typeset -Ttyp1 typ1=(
+	function get {
+	        .sh.value="'\''Sample'\''";
+	}
+)
+typeset -p .sh.type
+typ1
+command typ1 var11
+typ1
+print $var11
+print -v var11
+typeset -p .sh.type' 2>&1)
+
+exp='namespace sh.type
+{
+	:
+}
+namespace sh.type
+{
+	typeset -r typ1='\''Sample'\''
+}
+typ1 var11='\''Sample'\''
+'\''Sample'\''
+'\''Sample'\''
+namespace sh.type
+{
+	typeset -r typ1='\''Sample'\''
+}'
+
+[[ $got == "$exp" ]] || err_exit "'tyeset -p .sh.type' failed" \
+	"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
+
 # ======
 exit $((Errors<125?Errors:125))