BUG: Fix reference counting for subarrays containing objects (#12650)

* BUG: Fix dtype object subarrays for INCREF/DECREF and zeros/empty init

* BUG: VOID_copyswap cannot fast path nontrivial subarrays

Especially object dtypes need reference counting, so cannot use
memcpy. Subarrays that include fields also have data which should
not be overwritten.

* BUG: Copying subarrays with objects must decref original objects

When not using the dtype transfer function, the buffers are initialized
to NULL, and then just copied in full. Thus, at no point decref'ing
happens on the data that is originally in the array.

* TST: Test subarray field reference counting

Tests initialization, copying and repeating (incrementing) as
well as advanced indexing (uses copyswap currently) and assignment

* TST: Test sparse subarray field assignments

Assigning to subarray fields should not change the output in
between the fields. This currently still happens for normal
assignment, but not for advanced indexing.

The second test is marked as `pytest.mark.valgrind_error` to make
it clear that it is expected to show errors in valgrind, and give
at least the theoretical the possibility to skip it during testing.

0 files changed, 0 insertions, 0 deletions