POSIX allows assignments preceding special builtins such as ':', 'set',
etc. not only to persist but also to be persistently exported. I think
that exporting behaviour is inherently broken and it's unfortunate that
bash does this in POSIX mode, as it's merely allowed and not actually
mandated, but anyway...
What I'm reporting here is a bug I discovered with unexporting a
variable that is so exported while bash is in POSIX mode. It cannot be
unexported using 'typeset +x' if you try to do that in a shell function.
This works:
$ bash -o posix -c 'foo=abc : ; typeset +x foo; env|grep ^foo='
(no output, as expected: no longer exported)
But this doesn't:
$ bash -o posix -c 'fn() { foo=abc : ; typeset +x foo; env|grep ^foo=;
}; fn'
foo=abc
Bug confirmed on all bash versions down to 2.05b.
I've also succeeded in making 'unset -v' fail silently for a variable
that is so exported, but I've so far been unable to track down a
specific reproducer that is simple enough to post here. It occurred as a
failure in the modernish regression test suite, which is extensive.
Chet, let me know if you want a reproducer for that and I'll email you a
tarball plus instructions. It seems likely that fixing the bug reported
above would fix that one as well, though.
- M.
