guess_schema throwing exception

[learn-more]

When input data can't be decoded by guess_schema, (for example because it has a 'group' wire type,
it will thrown a TypeError: 'NoneType' object is not subscriptable.
That seems like it should either throw a relevant error, or return None.

What is the expected behavior on a failure case?

Minimal code to reproduce it:

from protodeep.lib import guess_schema
input_data = b'\x83\x01\x88\x01h\x84\x01\x92\x01\x02\x08i'
schema = guess_schema(data=input_data, bruteforce_index=0)

[mxrch]

Hey, thanks for your issue !
You're right, it should throw a more relevent error. I think I'll make a custom error that I'll raise in this case, so users can catch this error specifically !

[mxrch]

I'll update the issue when it's done :)
I'm a lil busy right now but I'm doing my best

[mxrch]

Are you ok with these changes ? fe01ca3

[learn-more]

If you want to thrown an exception in that function if it cannot decode it, that seems like a sensible approach,
however the exception being thrown right now is simply the result of a logic error, so I don't think catching any exception and replacing it with a ProtoDeepCannotDecode exception is the best approach.

This line:

ProtoDeep/protodeep/lib.py

Line 168 in e520680

parsed = schema[0]

Is trying to index None (returned by find_proto_schema if it cannot decode it),
so maybe that would be the correct place to raise the error?