This commit is a rebase of an old contribution with minor formatting
edits (cf. https://github.com/grpc/grpc/pull/8663)
[Original Author]
Masood Malekghassemi <atash@google.com>
Date: Mon Nov 7 14:49:09 2016 -0800
Contributor is a Xoogler and the contribution is owned by Google Inc.
as per the copyright assignment agreement with the original author,
as it was drafted during their employment with Google Inc.
Beta code elements are not generated at all in _pb2_grpc.py files.
This duplicates a lot of the in-test code generation done in
_split_definitions_test. In a future clean-up we may want to
deduplicate the common behavior, put it in a module available to all
other tests, and do all of our testing of generated code with in-test
code generation.
I made this mistake in 2010985ab2 but
only with yesterday's release of six 1.11.0 has it started failing
("TypeError: metaclass conflict: the metaclassof a derived class must
be a (non-strict) subclass of the metaclasses of all its bases").
We were mistaken before when we were testing _pb2.py files being
generated in one directory and _pb2_grpc.py files being generated in
another directory. Sure, that was a thing our code generator could do,
but because of the way paths and packages work in Python it wasn't a
realistic use case for actual users.
This test now tests _pb2.py files and _pb2_grpc.py files being
generated either together or independently of one another, and if
independently, in either order. Looking forward to an eventual
py_grpc_library Bazel rule, that's what actually matters.
- Move it out of the "unit" package, as it's not itself a unit test.
- Suffix the test class with "Test" as we do with every other subclass
of unittest.TestCase.
- Add a larger-than-we'll-need-any-time-soon maxDiff so that failures
are fully described.
- Relax the assertion from assertListEqual to assertSequenceEqual
since we don't actually care whether or not the sequences being
compared are list instances.
- Change the order of the assertions arguments to match the
"<expected>, <actual>" convention used in our assert*Equal calls
elsewhere throughout the test corpus.
- Internal implementation simplifications.
Were this not done these would break when the default behavior of gRPC
Python Protoc Plug-In is changed to be the put-gRPC-code-elements-only-
in-_pb2_grpc.py-files behavior that currently happens only when the
grpc_2_0 flag is passed.
The gRPC Core has two styles for passing metadata: as an integer count
along with a grpc_metadata* pointer, which is used for passing metadata
into the core, and as a grpc_metadata_array, which is used for passing
metadata out of the core. The Cython layer of gRPC Python was using a
single data structure wrapping grpc_metadata_array for both purposes,
but this was complex because the core manages the slices contained in
grpc_metadata_array objects (at least those of which it is aware), so
the Cython layer had to keep track of whether or not the core was aware
of the slices it was using (and it was also defective, leaking slices).
This is solved by realigning with the Cython layer’s intended design of
mirroring as closely as possible in Python the gRPC Core API: we use
one structure for passing metadata into the core (what is now called
cygrpc.Metadata) and second, different structure for receiving metadata
out of the core (what was called cygrpc.Metadata but is now
cygrpc.MetadataArray, reflecting that it wraps the core’s
grpc_metadata_array).
All bug fixes should contain added tests preventing regression but this
doesn't because I don't know at this time how to write a does-not-leak
test for Python that fits well into our existing body of tests. Phooey.
Thanks to Dominik Janků (djanku@email.cz) for investigation and an
earlier draft of a solution.
"proto" and "*.egg-info/" are no longer generated, "src/" can be
narrowed to "/src/", and "*_pb2.py" and "*_pb2_grpc.py" are covered by
.gitignore files in parent directories.
Nathaniel Manista