[PATCH] Fix crash on unset-through-nameref

[Bart Schaefer <schaefer@brasslantern.com>]

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On Sun, Mar 3, 2024 at 2:58 PM Bart Schaefer <schaefer@brasslantern.com> wrote:
>
> On Sun, Mar 3, 2024 at 12:27 PM Stephane Chazelas <stephane@chazelas.org> wrote:
> >
> > It segfaults with zsh -x though
>
> I'll have a look at that later, thanks.

Variation of the same problem reported by Jun T. when unsetting the
array part of a tied pair.

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diff --git a/Src/builtin.c b/Src/builtin.c
index 83144677b..b867ea094 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -3935,9 +3935,11 @@ bin_unset(char *name, char **argv, Options ops, int func)
 		int ref = (pm->node.flags & PM_NAMEREF);
 		if (!(pm = (Param)resolve_nameref(pm, NULL)))
 		    continue;
-		if (ref && pm->level < locallevel) {
+		if (ref && pm->level < locallevel &&
+		    !(pm->node.flags & PM_READONLY)) {
 		    /* Just mark unset, do not remove from table */
-		    pm->node.flags |= PM_DECLARED|PM_UNSET;
+		    stdunsetfn(pm, 0);
+		    pm->node.flags |= PM_DECLARED;
 		    continue;
 		}
 	    }
diff --git a/Test/K01nameref.ztst b/Test/K01nameref.ztst
index ff48e2289..5c123f122 100644
--- a/Test/K01nameref.ztst
+++ b/Test/K01nameref.ztst
@@ -669,6 +669,31 @@ F:Checking for a bug in zmodload that affects later tests
 >typeset -n ref=two
 >typeset -n ref=var
 
+ typeset -g .K01.scalar='RW'
+ typeset -gA .K01.assoc=(x y)
+ typeset -ga .K01.array=(z)
+ typeset -gi .K01.integer=0
+ typeset -gE .K01.double=0.0
+ typeset -gF .K01.float=0.0
+ typeset -gr .K01.readonly='RO'
+ typeset -n gref
+ for gref in ARGC .K01.{scalar,assoc,array,integer,double,float,readonly}
+ do
+   { unset gref } always { TRY_BLOCK_ERROR=0 }
+ done
+ typeset -p .K01.{scalar,assoc,array,integer,double,float,readonly}
+ unset .K01.{scalar,assoc,array,integer,double,float}
+0:unset various types via nameref, including a readonly special
+>typeset -g .K01.scalar
+>typeset -g -A .K01.assoc
+>typeset -g -a .K01.array
+>typeset -g -i .K01.integer
+>typeset -g -E .K01.double
+>typeset -g -F .K01.float
+>typeset -g -r .K01.readonly=RO
+*?*read-only variable: ARGC
+*?*read-only variable: .K01.readonly
+
  unset -n ref
  unset one
  typeset -n ref