Fix 'typeset -xu', 'typeset -xl' (rhbz#1188377)

'typeset -xu' and 'typeset -xl' would export the variable but fail
to change case in the value under certain conditions.

Original patch:
https://src.fedoraproject.org/rpms/ksh/blob/642af4d6/f/ksh-20120801-xufix.patch

This applies the patch essentially without change and adds a
regression test based on the reproducer provided in the RH bug.

Unfortunately there is no description of how the patch works and
it's a little obscure to me. As far as I can figure out, the cause
of the problem was that nv_newattr() erroneously processed a
nonexistent size option-argument such as what can be given to
options like typeset -F, e.g. typeset -F3 for 3 digits after the
dot. A nonexistent size argument is represented by the value of -1.

NEWS

@@ -3,6 +3,11 @@ For full details, see the git log at: https://github.com/ksh93/ksh
 
 Any uppercase BUG_* names are modernish shell bug IDs.
 
+2020-09-30:
+
+- Fixed: 'typeset -xu' and 'typeset -xl' (export + change case) failed to
+  change the case of a variable's value in certain conditions.
+
 2020-09-28:
 
 - While executing a ksh-style function, ksh 93u+ ignored all signals for which

src/cmd/ksh93/bltins/typeset.c

@@ -94,6 +94,7 @@ int    b_readonly(int argc,char *argv[],Shbltin_t *context)
 	memset((void*)&tdata,0,sizeof(tdata));
 	tdata.sh = context->shp;
 	tdata.aflag = '-';
+	tdata.argnum = -1;  /* tell nv_newattr() that we should not change size */
 	while((flag = optget(argv,*command=='e'?sh_optexport:sh_optreadonly))) switch(flag)
 	{
 		case 'p':

src/cmd/ksh93/include/version.h

@@ -17,4 +17,4 @@
 *                  David Korn <dgk@research.att.com>                   *
 *                                                                      *
 ***********************************************************************/
-#define SH_RELEASE	"93u+m 2020-09-28"
+#define SH_RELEASE	"93u+m 2020-09-30"

src/cmd/ksh93/sh/name.c

@@ -2954,10 +2954,12 @@ void nv_newattr (register Namval_t *np, unsigned newatts, int size)
 			nv_onattr(np,NV_EXPORT);
 			sh_envput(shp->env,np);
 		}
-		if((n^newatts)==NV_EXPORT)
+		if((n^newatts)==NV_EXPORT && size==-1)
 			return;
 	}
 	oldsize = nv_size(np);
+	if(size==-1)
+		size = oldsize;
 	if((size==oldsize|| (n&NV_INTEGER)) && !trans && ((n^newatts)&~NV_NOCHANGE)==0)
 	{
 		if(size)

src/cmd/ksh93/tests/attributes.sh

@@ -30,6 +30,23 @@ integer Errors=0
 
 [[ -d $tmp && -w $tmp && $tmp == "$PWD" ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
+# ======
+# as of 93u+, typeset -xu/-xl failed to change case in a value (rhbz#1188377)
+# (this test failed to fail when it was added at the end, so it's at the start)
+unset test_u test_xu test_txu
+typeset -u test_u=uppercase
+typeset -xu test_xu=uppercase
+typeset -txu test_txu=uppercase
+typeset -l test_l=LOWERCASE
+typeset -xl test_xl=LOWERCASE
+typeset -txl test_txl=LOWERCASE
+exp="UPPERCASE UPPERCASE UPPERCASE lowercase lowercase lowercase"
+got="${test_u} ${test_xu} ${test_txu} ${test_l} ${test_xl} ${test_txl}"
+[[ $got == "$exp" ]] || err_exit "typeset failed to change case in variable" \
+	"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
+unset ${!test_*}
+
+# ======
 r=readonly u=Uppercase l=Lowercase i=22 i8=10 L=abc L5=def uL5=abcdef xi=20
 x=export t=tagged H=hostname LZ5=026 RZ5=026 Z5=123 lR5=ABcdef R5=def n=l
 for option in u l i i8 L L5 LZ5 RZ5 Z5 r x H t R5 uL5 lR5 xi n