GIN tries to form a tuple with a partial compressedList during insertion

Hi,

In the functions addItemPointersToLeafTuple and buildFreshLeafTuple
(in gininsert.c), the result of ginCompressPostingList()
is passed to GinFormTuple without checking whether
ginCompressPostingList() successfully packed all items.
These GinFormTuple calls consistently fail because the resulting
tuples always exceed the maximum size.
While this doesn’t result in data corruption, it might still be worth
addressing.
Additionally, the condition if (compressedList) is unnecessary, since
ginCompressPostingList() never returns NULL.

Please find the attached patch fixing it.

Best regards,
Arseniy Mukhin