Patch protobuf and grpc dependencies to be Python 3.10 compatible.

WORKSPACE

@@ -110,6 +110,24 @@ sass_repositories()
 # might lead to test failures.
 http_archive(
     name = "com_google_protobuf",
+    patch_args = ["-p1"],
+    patches = [
+        # To maintain compatibility with python 3.10 and greater, we need to patch
+        # in the following protobuf change:
+        # https://github.com/grpc/grpc/commit/9d61eada0f47d7be793983638c4a29707b192d0c
+        #
+        # To reproduce the patch:
+        # ```
+        # $ git clone https://github.com/protocolbuffers/protobuf.git
+        # $ cd protobuf
+        # $ git checkout tags/v3.9.2 -b my-patch
+        # $ git cherry-pick 9d61eada0f47d7be793983638c4a29707b192d0c
+        # $ git diff HEAD~1 > protobuf.patch
+        # # Remove trailing whitespace to satisify whitespace_hygiene_test.py.
+        # $ sed -i 's/[[:space:]]*$//' protobuf.patch
+        # ```
+        "//third_party:protobuf.patch",
+    ],
     sha256 = "1fbf1c2962af287607232b2eddeaec9b4f4a7a6f5934e1a9276e9af76952f7e0",
     strip_prefix = "protobuf-3.9.2",
     urls = [
@@ -121,12 +139,34 @@ http_archive(
 # gRPC.
 http_archive(
     name = "com_github_grpc_grpc",
+    patch_args = ["-p1"],
+    patches = [
+        # To maintain compatibility with python 3.10 and greater, we need to patch
+        # in the following grpc change:
+        # https://github.com/grpc/grpc/commit/dbe73c9004e483d24168c220cd589fe1824e72bc
+        #
+        # To reproduce the patch:
+        # ```
+        # $ git clone https://github.com/grpc/grpc.git
+        # $ cd grpc
+        # $ git checkout tags/v1.27.0-pre1 -b my-patch
+        # $ git cherry-pick dbe73c9004e483d24168c220cd589fe1824e72bc
+        # $ git diff HEAD~1 > grpc.patch
+        # ```
+        #
+        # Note that we choose tags/v1.27.0-pre1 as the base since the version in
+        # the archive is 1.27.0-dev. It's not necessarily an exact match but is
+        # the best guess we can make for a match.
+        "//third_party:grpc.patch",
+    ],
     sha256 = "b956598d8cbe168b5ee717b5dafa56563eb5201a947856a6688bbeac9cac4e1f",
     strip_prefix = "grpc-b54a5b338637f92bfcf4b0bc05e0f57a5fd8fadd",
     urls = [
         # Same as TF: https://github.com/tensorflow/tensorflow/blob/master/tensorflow/workspace2.bzl#L492
         # Currently we can't upgrade gRPC past 1.30.0 without also bumping protobuf to 3.12.0+:
         # https://github.com/grpc/grpc/issues/23311.
+        #
+        # Inspecting the contents of this archive, the version is 1.27.0-dev.
         "http://mirror.tensorflow.org/github.com/grpc/grpc/archive/b54a5b338637f92bfcf4b0bc05e0f57a5fd8fadd.tar.gz",
         "https://github.com/grpc/grpc/archive/b54a5b338637f92bfcf4b0bc05e0f57a5fd8fadd.tar.gz",
     ],

third_party/grpc.patch

@@ -0,0 +1,33 @@
+diff --git a/third_party/py/python_configure.bzl b/third_party/py/python_configure.bzl
+index 34501c3212..7f178f4009 100644
+--- a/third_party/py/python_configure.bzl
++++ b/third_party/py/python_configure.bzl
+@@ -198,8 +198,8 @@ def _get_python_lib(repository_ctx, python_bin, lib_path_key):
+         "  python_paths = os.getenv('PYTHONPATH').split(':')\n" + "try:\n" +
+         "  library_paths = site.getsitepackages()\n" +
+         "except AttributeError:\n" +
+-        " from distutils.sysconfig import get_python_lib\n" +
+-        " library_paths = [get_python_lib()]\n" +
++        " import sysconfig\n" +
++        " library_paths = [sysconfig.get_path('purelib')]\n" +
+         "all_paths = set(python_paths + library_paths)\n" + "paths = []\n" +
+         "for path in all_paths:\n" + "  if os.path.isdir(path):\n" +
+         "    paths.append(path)\n" + "if len(paths) >=1:\n" +
+@@ -232,14 +232,13 @@ def _get_python_include(repository_ctx, python_bin):
+             python_bin,
+             "-c",
+             "from __future__ import print_function;" +
+-            "from distutils import sysconfig;" +
+-            "print(sysconfig.get_python_inc())",
++            "import sysconfig;" +
++            "print(sysconfig.get_path('include'))",
+         ],
+         error_msg = "Problem getting python include path for {}.".format(python_bin),
+         error_details = (
+             "Is the Python binary path set up right? " + "(See ./configure or " +
+-            python_bin + ".) " + "Is distutils installed? " +
+-            _HEADERS_HELP
++            python_bin + ".) " + _HEADERS_HELP
+         ),
+     )
+     include_path = result.stdout.splitlines()[0]

third_party/protobuf.patch

@@ -0,0 +1,18 @@
+diff --git a/python/google/protobuf/pyext/message.cc b/python/google/protobuf/pyext/message.cc
+index 3530a9b37..c31fa8fcc 100644
+--- a/python/google/protobuf/pyext/message.cc
++++ b/python/google/protobuf/pyext/message.cc
+@@ -2991,8 +2991,12 @@ bool InitProto2MessageModule(PyObject *m) {
+         reinterpret_cast<PyObject*>(
+             &RepeatedCompositeContainer_Type));
+
+-    // Register them as collections.Sequence
++    // Register them as MutableSequence.
++#if PY_MAJOR_VERSION >= 3
++    ScopedPyObjectPtr collections(PyImport_ImportModule("collections.abc"));
++#else
+     ScopedPyObjectPtr collections(PyImport_ImportModule("collections"));
++#endif
+     if (collections == NULL) {
+       return false;
+     }