48560: add TYPESET_TO_UNSET option to remove initialization of parameters

Changes typeset such that ${newparam-notset} yields "notset" and
"typeset -p newparam" does not show an assignment to the parameter.  This
is similar to the default behavior of bash and ksh, with minor differences
in typeset output.

Also add tests for some POSIX incompatibilities plus minor changes for test
harness robustness.

5 files changed, 36 insertions, 7 deletions

diff --git a/Src/builtin.c b/Src/builtin.c
index 26335a2e8..6d119f7a5 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -2491,6 +2491,8 @@ typeset_single(char *cname, char *pname, Param pm, UNUSED(int func),
 		return NULL;
 	    }
 	}
+	if (isset(TYPESETTOUNSET))
+	    pm->node.flags |= PM_DEFAULTED;
     } else {
 	if (idigit(*pname))
 	    zerrnam(cname, "not an identifier: %s", pname);
@@ -2836,7 +2838,7 @@ bin_typeset(char *name, char **argv, LinkList assigns, Options ops, int func)
 	    unqueue_signals();
 	    return 1;
 	} else if (pm) {
-	    if (!(pm->node.flags & PM_UNSET)
+	    if ((!(pm->node.flags & PM_UNSET) || pm->node.flags & PM_DECLARED)
 		&& (locallevel == pm->level || !(on & PM_LOCAL))) {
 		if (pm->node.flags & PM_TIED) {
 		    if (PM_TYPE(pm->node.flags) != PM_SCALAR) {
@@ -2889,6 +2891,8 @@ bin_typeset(char *name, char **argv, LinkList assigns, Options ops, int func)
 	 *
 	 * Don't attempt to set it yet, it's too early
 	 * to be exported properly.
+	 *
+	 * This may create the array with PM_DEFAULTED.
 	 */
 	asg2.name = asg->name;
 	asg2.flags = 0;
@@ -2930,8 +2934,12 @@ bin_typeset(char *name, char **argv, LinkList assigns, Options ops, int func)
 	if (asg->value.array) {
 	    int flags = (asg->flags & ASG_KEY_VALUE) ? ASSPM_KEY_VALUE : 0;
 	    assignaparam(asg->name, zlinklist2array(asg->value.array, 1), flags);
-	} else if (oldval)
-	    assignsparam(asg0.name, oldval, 0);
+	} else if (asg0.value.scalar || oldval) {
+	    /* We have to undo what we did wrong with asg2 */
+	    apm->node.flags &= ~PM_DEFAULTED;
+	    if (oldval)
+		assignsparam(asg0.name, oldval, 0);
+	}
 	unqueue_signals();
 
 	return 0;
diff --git a/Src/options.c b/Src/options.c
index 6ea6290e5..783022591 100644
--- a/Src/options.c
+++ b/Src/options.c
@@ -259,6 +259,7 @@ static struct optname optns[] = {
 {{NULL, "transientrprompt",   0},			 TRANSIENTRPROMPT},
 {{NULL, "trapsasync",	      0},			 TRAPSASYNC},
 {{NULL, "typesetsilent",      OPT_EMULATE|OPT_BOURNE},	 TYPESETSILENT},
+{{NULL, "typesettounset",     OPT_EMULATE|OPT_BOURNE},	 TYPESETTOUNSET},
 {{NULL, "unset",	      OPT_EMULATE|OPT_BSHELL},	 UNSET},
 {{NULL, "verbose",	      0},			 VERBOSE},
 {{NULL, "vi",		      0},			 VIMODE},
diff --git a/Src/params.c b/Src/params.c
index 122f5da7d..33bbc54f6 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -2093,7 +2093,8 @@ fetchvalue(Value v, char **pptr, int bracks, int flags)
 	if (sav)
 	    *s = sav;
 	*pptr = s;
-	if (!pm || (pm->node.flags & PM_UNSET))
+	if (!pm || ((pm->node.flags & PM_UNSET) &&
+		    !(pm->node.flags & PM_DECLARED)))
 	    return NULL;
 	if (v)
 	    memset(v, 0, sizeof(*v));
@@ -3055,6 +3056,7 @@ assignsparam(char *s, char *val, int flags)
 	     * Don't warn about anything.
 	     */
 	    flags &= ~ASSPM_WARN;
+	    v->pm->node.flags &= ~PM_DEFAULTED;
 	}
 	*ss = '[';
 	v = NULL;
@@ -3080,6 +3082,7 @@ assignsparam(char *s, char *val, int flags)
     }
     if (flags & ASSPM_WARN)
 	check_warn_pm(v->pm, "scalar", created, 1);
+    v->pm->node.flags &= ~PM_DEFAULTED;
     if (flags & ASSPM_AUGMENT) {
 	if (v->start == 0 && v->end == -1) {
 	    switch (PM_TYPE(v->pm->node.flags)) {
@@ -3232,6 +3235,7 @@ assignaparam(char *s, char **val, int flags)
 
     if (flags & ASSPM_WARN)
 	check_warn_pm(v->pm, "array", created, may_warn_about_nested_vars);
+    v->pm->node.flags &= ~PM_DEFAULTED;
 
     /*
      * At this point, we may have array entries consisting of
@@ -3444,6 +3448,7 @@ sethparam(char *s, char **val)
 	    return NULL;
 	}
     check_warn_pm(v->pm, "associative array", checkcreate, 1);
+    v->pm->node.flags &= ~PM_DEFAULTED;
     setarrvalue(v, val);
     unqueue_signals();
     return v->pm;
@@ -3515,6 +3520,7 @@ assignnparam(char *s, mnumber val, int flags)
 	if (flags & ASSPM_WARN)
 	    check_warn_pm(v->pm, "numeric", 0, 1);
     }
+    v->pm->node.flags &= ~PM_DEFAULTED;
     setnumvalue(v, val);
     unqueue_signals();
     return v->pm;
@@ -3619,6 +3625,7 @@ unsetparam_pm(Param pm, int altflag, int exp)
     else
 	altremove = NULL;
 
+    pm->node.flags &= ~PM_DECLARED;	/* like ksh, not like bash */
     if (!(pm->node.flags & PM_UNSET))
 	pm->gsu.s->unsetfn(pm, exp);
     if (pm->env)
@@ -3652,6 +3659,8 @@ unsetparam_pm(Param pm, int altflag, int exp)
 	}
 
 	zsfree(altremove);
+	if (!(pm->node.flags & PM_SPECIAL))
+	    pm->gsu.s = &stdscalar_gsu;
     }
 
     /*
@@ -4116,6 +4125,11 @@ tiedarrsetfn(Param pm, char *x)
 
     if (*dptr->arrptr)
 	freearray(*dptr->arrptr);
+    else if (pm->ename) {
+	Param altpm = (Param) paramtab->getnode(paramtab, pm->ename);
+	if (altpm)
+	    altpm->node.flags &= ~PM_DEFAULTED;
+    }
     if (x) {
 	char sepbuf[3];
 	if (imeta(dptr->joinchar))
@@ -5035,6 +5049,7 @@ arrfixenv(char *s, char **t)
 
     if (isset(ALLEXPORT))
 	pm->node.flags |= PM_EXPORTED;
+    pm->node.flags &= ~PM_DEFAULTED;
 
     /*
      * Do not "fix" parameters that were not exported
@@ -5839,8 +5854,9 @@ printparamnode(HashNode hn, int printflags)
     Param peer = NULL;
 
     if (p->node.flags & PM_UNSET) {
-	if (printflags & (PRINT_POSIX_READONLY|PRINT_POSIX_EXPORT) &&
-	    p->node.flags & (PM_READONLY|PM_EXPORTED)) {
+	if ((printflags & (PRINT_POSIX_READONLY|PRINT_POSIX_EXPORT) &&
+	     p->node.flags & (PM_READONLY|PM_EXPORTED)) ||
+	    (p->node.flags & PM_DEFAULTED) == PM_DEFAULTED) {
 	    /*
 	     * Special POSIX rules: show the parameter as readonly/exported
 	     * even though it's unset, but with no value.
diff --git a/Src/subst.c b/Src/subst.c
index 96e0914eb..9928be0e9 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -2563,7 +2563,8 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags,
 	     * Handle the (t) flag: value now becomes the type
 	     * information for the parameter.
 	     */
-	    if (v && v->pm && !(v->pm->node.flags & PM_UNSET)) {
+	    if (v && v->pm && ((v->pm->node.flags & PM_DECLARED) ||
+			       !(v->pm->node.flags & PM_UNSET))) {
 		int f = v->pm->node.flags;
 
 		switch (PM_TYPE(f)) {
diff --git a/Src/zsh.h b/Src/zsh.h
index d70a4017c..af9b4fb67 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -1929,8 +1929,10 @@ struct tieddata {
 				   made read-only by the user               */
 #define PM_READONLY_SPECIAL (PM_SPECIAL|PM_READONLY|PM_RO_BY_DESIGN)
 #define PM_DONTIMPORT	(1<<22)	/* do not import this variable              */
+#define PM_DECLARED	(1<<22) /* explicitly named with typeset            */
 #define PM_RESTRICTED	(1<<23) /* cannot be changed in restricted mode     */
 #define PM_UNSET	(1<<24)	/* has null value                           */
+#define PM_DEFAULTED	(PM_DECLARED|PM_UNSET)
 #define PM_REMOVABLE	(1<<25)	/* special can be removed from paramtab     */
 #define PM_AUTOLOAD	(1<<26) /* autoloaded from module                   */
 #define PM_NORESTORE	(1<<27)	/* do not restore value of local special    */
@@ -2536,6 +2538,7 @@ enum {
     TRANSIENTRPROMPT,
     TRAPSASYNC,
     TYPESETSILENT,
+    TYPESETTOUNSET,
     UNSET,
     VERBOSE,
     VIMODE,