[PATCH] ASS_NOEVAL for BASHOPTS and SHELLOPTS

[Grisha Levit]

(Prompted by the report from Emanuele Torre in [1])

The value of currently_executing_command is garbage when there is an error
during assignment when popping the variable context:

    $ bash -c 'declare -i SHELLOPTS; f() { local -; set -f; }; f' |& cat -v
    bash: line 1: M-`^WM-R^N^\{: braceexpand:hashall:interactive-comment...

    $ bash-asan -c 'declare -i SHELLOPTS; f() { local -; set -f; }; f'
    SUMMARY: AddressSanitizer: heap-use-after-free execute_cmd.c:399 in
    executing_line_number

[1]: https://lists.gnu.org/archive/html/bug-bash/2024-01/msg00111.html

I'm not sure that allowing the integer attribute to be changed really makes
sense for readonly variables but, in any case, the following should prevent
the issue here:

diff --git a/builtins/set.def b/builtins/set.def
index e0024a97..05f3f942 100644
--- a/builtins/set.def
+++ b/builtins/set.def
@@ -578,7 +578,7 @@ set_shellopts (void)
   exported = v ? exported_p (v) : 0;

   /* ASS_FORCE so we don't have to temporarily turn off readonly */
-  v = bind_variable ("SHELLOPTS", value, ASS_FORCE);
+  v = bind_variable ("SHELLOPTS", value, ASS_FORCE|ASS_NOEVAL);

   /* Turn the read-only attribute back on, and turn off the export attribute
      if it was set implicitly by mark_modified_vars and SHELLOPTS was not
diff --git a/builtins/shopt.def b/builtins/shopt.def
index e6c77cc5..95459bbc 100644
--- a/builtins/shopt.def
+++ b/builtins/shopt.def
@@ -854,7 +854,7 @@ set_bashopts (void)
   exported = v ? exported_p (v) : 0;

   /* ASS_FORCE so we don't have to temporarily turn off readonly */
-  v = bind_variable ("BASHOPTS", value, ASS_FORCE);
+  v = bind_variable ("BASHOPTS", value, ASS_FORCE|ASS_NOEVAL);

   /* Turn the read-only attribute back on, and turn off the export attribute
      if it was set implicitly by mark_modified_vars and SHELLOPTS was not