[PATCH] Re: set -o nounset; foo=(); print ${foo:#bar}

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Sep 6, 12:34pm, Bart Schaefer wrote:
} Subject: Re: set -o nounset; foo=(); print ${foo:#bar}
}
} On Sep 6,  8:47pm, Roman Neuhauser wrote:
} }
} }   roman@wrench ~ 0 1078 0 > print ${foo:#bar}
} }   zsh: foo: parameter not set
} }   roman@wrench ~ 0 1079 1 > 
} } 
} } the problematic part is ${foo:#bar} triggering nounset.  FMPOV it *is*
} } set (but null), so i'd say the observed behavior is a bug.
} 
} This seems to be ${name:#word} being confused with ${name:?word} where
} the ":" means to treat an empty parameter as unset.  This also affects
} the newer ${name:^word} form.


I believe this fixes it; all tests still pass including the NOUNSET tests
on ${array1:^array2}.


diff --git a/Src/subst.c b/Src/subst.c
index 4a5fe3a..1aa9b98 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -1522,6 +1522,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
      * unset.  I don't quite understand why (v == NULL) isn't
      * good enough, but there are places where we seem to need
      * to second guess whether a value is a real value or not.
+     * See in particular the (colf && !vunset) test below.
      */
     int vunset = 0;
     /*
@@ -2638,8 +2639,10 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 	 * - (array) contains no elements
 	 * - (scalar) contains an empty string
 	 */
-	if (colf && !vunset)
+	if (colf && !vunset) {
 	    vunset = (isarr) ? !*aval : !*val || (*val == Nularg && !val[1]);
+	    vunset *= -1; /* Record that vunset was originally false */
+	}
 
 	switch (s[-1]) {
 	case '+':
@@ -2862,7 +2865,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 		getmatcharr(&aval, s, flags, flnum, replstr);
 	    } else {
 		if (vunset) {
-		    if (unset(UNSET)) {
+		    if (vunset > 0 && unset(UNSET)) {
 			*idend = '\0';
 			zerr("%s: parameter not set", idbeg);
 			return NULL;
@@ -2892,7 +2895,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 	    return NULL;
 	}
 	if (vunset) {
-	    if (unset(UNSET)) {
+	    if (vunset > 0 && unset(UNSET)) {
 		*idend = '\0';
 		zerr("%s: parameter not set", idbeg);
 		return NULL;
@@ -2974,7 +2977,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 		*ap = NULL;
 	    } else {
 		if (vunset) {
-		    if (unset(UNSET)) {
+		    if (vunset > 0 && unset(UNSET)) {
 			*idend = '\0';
 			zerr("%s: parameter not set", idbeg);
 			deletehashtable(ht);
@@ -3003,7 +3006,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 	    }
 	}
 	if (vunset) {
-	    if (unset(UNSET)) {
+	    if (vunset > 0 && unset(UNSET)) {
 		*idend = '\0';
 		zerr("%s: parameter not set", idbeg);
 		return NULL;
@@ -3020,7 +3023,7 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 	    val = dupstring(vunset ? "0" : "1");
 	    isarr = 0;
 	} else if (vunset) {
-	    if (unset(UNSET)) {
+	    if (vunset > 0 && unset(UNSET)) {
 		*idend = '\0';
 		zerr("%s: parameter not set", idbeg);
 		return NULL;