[pypy-dev] cppyy questions

[Omer Katz]

I'm trying to use protobuf with PyPy and I've been quite successful doing
so with cppyy.
I generated the protobuf in C++ and used reflex to generate the bindings.
I've encountered some problems that I don't know how to deal with and the
documentation doesn't describe what you can do to resolve them.

I discovered that If you don't specify --deep when generating the reflex
bindings and you try to pass a string to the C++ side you get a segfault.
I'm guessing that's a bug.

I can't catch exceptions that are being raised from C++ (it's also
undocumented).
I ensured that protobuf's FatalException has reflex bindings but the
process crashes on an exception.

e.SerializeAsString()
[libprotobuf FATAL google/protobuf/message_lite.cc:273] CHECK failed:
IsInitialized(): Can't serialize message of type "MyProtobufType" because
it is missing required fields: header
terminate called after throwing an instance of
'google::protobuf::FatalException'
  what():  CHECK failed: IsInitialized(): Can't serialize message of type
"MyProtobufType" because it is missing required fields: header
Aborted (core dumped)

How can I catch that exception?


The documentation is unclear how you can pass a pointer to a Python
variable e.g.:
str = ""

e.SerializeToString(str)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-7-993880892d74> in <module>()
----> 1 e.SerializeToString(str)

TypeError: none of the 5 overloaded methods succeeded. Full details:
  bool google::protobuf::MessageLite::SerializeToString(std::string*) =>
    TypeError: cannot pass str as basic_string<char>
  bool google::protobuf::MessageLite::SerializeToString(std::string*) =>
    TypeError: cannot pass str as basic_string<char>
  bool google::protobuf::MessageLite::SerializeToString(std::string*) =>
    TypeError: cannot pass str as basic_string<char>
  bool google::protobuf::MessageLite::SerializeToString(std::string*) =>
    TypeError: cannot pass str as basic_string<char>
  bool google::protobuf::MessageLite::SerializeToString(std::string*) =>
    TypeError: cannot pass str as basic_string<char>

Best Regards,
Omer Katz.
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