Summary:
This is the Python 3.5+ version of our C API found in
include/mg_procedure.h. It should strive to be simple to use, but very
hard to misuse. The Python API avoids almost all memory management
issues found in the C API, so it is automatically less error prone.
Unfortunately, we cannot avoid the issue of having some objects being
alive only during the execution of a custom procedure. For such objects
we have a `Invalid<Object>Error` exception types. The Python API should
fairly easily check the validity because all such objects are related to
ProcCtx in some way. Our C/C++ part will push 1 instance of ProcCtx each
time a Python procedure is invoked and can therefore easily change
ProcCtx to be invalid. This can be as simple as changing the
implementation pointer of ProcCtx to NULL.
Reviewers: mferencevic, ipaljak, tlastre, dsantl, buda
Reviewed By: mferencevic, tlastre
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2650
