sexp: Fix broken gcry_sexp_nth.
* src/sexp.c (_gcry_sexp_nth): Return a valid S-expression for a data element. (NODE): Remove unused typedef. (ST_HINT): Comment unused macro. * tests/t-sexp.c (bug_1594): New. (main): Run new test.
Before 1.6.0 gcry_sexp_nth (list, 0) with a LIST of "(a (b 3:pqr) (c
3:456) (d 3:xyz))" returned the entire list. 1.6.0 instead returned
NULL. However, this is also surprising and the expected value would
be "(a)". This patch fixes this.
Somewhat related to that gcry_sexp_nth returned a broken list if
requesting index 1 of a list like "(n foo)". It returned just the
"foo" but not as a list which is required by the S-expression specs.
Due to this patch the returned value is now "(foo)".
Thanks to Ludovic Courtès for pointing out these problems.
- GnuPG-bug-id: T1594