Loads Hangs on Truncated Ion Container

[rmarrowstone]

When using the c extension on an Ion Value Stream that ends prematurely within an Ion Container, but not within a scalar value inside it, loads hangs indefinitely.

For example:

import amazon.ion.simpleion as ion 
ion.loads(b'\xe0\x01\x00\xea\xb6') # a 6 octet list is declared, stream ends before value is provided

premature ends within scalars appears to work fine:

ion.loads(b'\xe0\x01\x00\xea!') # a top-level Ion Int is declared, stream ends before value is provided
ion.loads(b'\xe0\x01\x00\xea\xb2!') # value within a 6 octet list ends prematurely itself.

It looks like there needs to be a check in ioncmodule.c for this. I suspect the root of the problem there is that ion-c returns tid_EOF for both EOF and end of each container. So an EOF is expected within a container.

[rmarrowstone]

Created amazon-ion/ion-c#355 which appears to be the cause.

[rmarrowstone]

I have merged a fix for this in ion-c. Folks who are relying on PyPI and/or built wheels will need to wait for a new release.

I'm going to update the submodule, once that is done then folks who are building from source can get the fix until it is actually released.