Strip out code that depends on PyProto_API when exporting from Google codebase to GitHub.

For context see #161, in particular #161 (comment).

Intentionally not stripping out the check_unknown_fields.h,cc sources:

1. For simplicity, and

2. so that it is more obvious externally what the corresponding code in
   pybind11_protobuf/tests/extension_test.py is about
   (stripping out the test code would lead to distracting clutter).

PiperOrigin-RevId: 645462442

Author: rwgk

CMakeLists.txt

@@ -68,10 +68,7 @@ add_library(
   # bazel: pybind_library: proto_cast_util
   pybind11_protobuf/proto_cast_util.cc
   pybind11_protobuf/proto_cast_util.h
-  pybind11_protobuf/proto_caster_impl.h
-  # bazel: cc_library::check_unknown_fields
-  pybind11_protobuf/check_unknown_fields.cc
-  pybind11_protobuf/check_unknown_fields.h)
+  pybind11_protobuf/proto_caster_impl.h)
 
 target_link_libraries(
   pybind11_native_proto_caster
@@ -98,10 +95,7 @@ add_library(
   # bazel: pybind_library: proto_cast_util
   pybind11_protobuf/proto_cast_util.cc
   pybind11_protobuf/proto_cast_util.h
-  pybind11_protobuf/proto_caster_impl.h
-  # bazel: cc_library: check_unknown_fields
-  pybind11_protobuf/check_unknown_fields.cc
-  pybind11_protobuf/check_unknown_fields.h)
+  pybind11_protobuf/proto_caster_impl.h)
 
 target_link_libraries(
   pybind11_wrapped_proto_caster
@@ -119,9 +113,6 @@ target_include_directories(
   PRIVATE ${PROJECT_SOURCE_DIR} ${protobuf_INCLUDE_DIRS} ${protobuf_SOURCE_DIR}
           ${pybind11_INCLUDE_DIRS})
 
-# TODO set defines PYBIND11_PROTOBUF_ENABLE_PYPROTO_API see: bazel:
-# pybind_library: proto_cast_util
-
 # bazel equivs. checklist
 #
 # bazel: pybind_library: enum_type_caster - enum_type_caster.h

pybind11_protobuf/BUILD

@@ -1,7 +1,6 @@
 # Pybind11 bindings for Google's Protocol Buffers
 
 load("@pybind11_bazel//:build_defs.bzl", "pybind_library")
-load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
 
 licenses(["notice"])
 
@@ -30,32 +29,13 @@ pybind_library(
     ],
 )
 
-# To enable PyProto_API use, specify:
-# bazel build --@//:enable_pyproto_api
-bool_flag(
-  name = "enable_pyproto_api",
-  build_setting_default = False,
-)
-
-config_setting(
-    name = "enable_pyproto_api_setting",
-    flag_values = {
-        ":enable_pyproto_api": "True",
-    },
-    visibility = ["//visibility:private"],
-)
-
 pybind_library(
     name = "proto_cast_util",
     srcs = ["proto_cast_util.cc"],
     hdrs = [
         "proto_cast_util.h",
         "proto_caster_impl.h",
     ],
-    local_defines = select({
-        ":enable_pyproto_api_setting": ["PYBIND11_PROTOBUF_ENABLE_PYPROTO_API"],
-        "//conditions:default": [],
-    }),
     deps = [
         ":check_unknown_fields",
         "@com_google_absl//absl/container:flat_hash_map",

pybind11_protobuf/native_proto_caster.h

@@ -20,7 +20,6 @@
 
 #include "google/protobuf/message.h"
 #include "absl/strings/string_view.h"
-#include "pybind11_protobuf/check_unknown_fields.h"
 #include "pybind11_protobuf/enum_type_caster.h"
 #include "pybind11_protobuf/proto_caster_impl.h"
 
@@ -64,8 +63,6 @@ inline void ImportNativeProtoCasters() { InitializePybindProtoCastUtil(); }
 inline void AllowUnknownFieldsFor(
     absl::string_view top_message_descriptor_full_name,
     absl::string_view unknown_field_parent_message_fqn) {
-  check_unknown_fields::AllowUnknownFieldsFor(top_message_descriptor_full_name,
-                                              unknown_field_parent_message_fqn);
 }
 
 }  // namespace pybind11_protobuf