Revive C++20 / C++23 tests

tools/run_tests/helper_scripts/build_cxx.sh

@@ -24,7 +24,7 @@ INSTALL_PATH="$(pwd)/cmake/install"
 cd third_party/abseil-cpp
 mkdir build
 cd build
-cmake -DCMAKE_CXX_STANDARD=14 -DABSL_BUILD_TESTING=OFF -DCMAKE_BUILD_TYPE="${MSBUILD_CONFIG}" -DCMAKE_INSTALL_PREFIX="${INSTALL_PATH}" "$@" ..
+cmake -DABSL_BUILD_TESTING=OFF -DCMAKE_BUILD_TYPE="${MSBUILD_CONFIG}" -DCMAKE_INSTALL_PREFIX="${INSTALL_PATH}" "$@" ..
 make -j"${GRPC_RUN_TESTS_JOBS}" install
 
 # Install opentelemetry-cpp since we only support "package" mode for opentelemetry at present.
@@ -32,7 +32,7 @@ cd ../../..
 cd third_party/opentelemetry-cpp
 mkdir build
 cd build
-cmake -DCMAKE_CXX_STANDARD=14 -DWITH_ABSEIL=ON -DBUILD_TESTING=OFF -DWITH_BENCHMARK=OFF -DCMAKE_BUILD_TYPE="${MSBUILD_CONFIG}" -DCMAKE_INSTALL_PREFIX="${INSTALL_PATH}" "$@" ..
+cmake -DWITH_ABSEIL=ON -DBUILD_TESTING=OFF -DWITH_BENCHMARK=OFF -DCMAKE_BUILD_TYPE="${MSBUILD_CONFIG}" -DCMAKE_INSTALL_PREFIX="${INSTALL_PATH}" "$@" ..
 make -j"${GRPC_RUN_TESTS_JOBS}" install
 
 cd ../../..
@@ -41,9 +41,9 @@ cd cmake/build
 
 # TODO(yashykt/veblush): Remove workaround after fixing b/332425004 
 if [ "${GRPC_RUNTESTS_ARCHITECTURE}" = "x86" ]; then
-cmake -DCMAKE_CXX_STANDARD=14 -DgRPC_BUILD_TESTS=ON -DCMAKE_BUILD_TYPE="${MSBUILD_CONFIG}" "$@" ../..
+cmake -DgRPC_BUILD_TESTS=ON -DCMAKE_BUILD_TYPE="${MSBUILD_CONFIG}" "$@" ../..
 else
-cmake -DCMAKE_CXX_STANDARD=14 -DgRPC_BUILD_GRPCPP_OTEL_PLUGIN=ON -DgRPC_ABSL_PROVIDER=package -DgRPC_BUILD_TESTS=ON -DCMAKE_BUILD_TYPE="${MSBUILD_CONFIG}" -DCMAKE_INSTALL_PREFIX="${INSTALL_PATH}" "$@" ../..
+cmake -DgRPC_BUILD_GRPCPP_OTEL_PLUGIN=ON -DgRPC_ABSL_PROVIDER=package -DgRPC_BUILD_TESTS=ON -DCMAKE_BUILD_TYPE="${MSBUILD_CONFIG}" -DCMAKE_INSTALL_PREFIX="${INSTALL_PATH}" "$@" ../..
 fi
 
 # GRPC_RUN_TESTS_CXX_LANGUAGE_SUFFIX will be set to either "c" or "cxx"

tools/run_tests/run_tests.py

@@ -568,7 +568,13 @@ class CLanguage(object):
             _check_compiler(compiler, ["default", "cmake"])
 
         if compiler == "default" or compiler == "cmake":
-            return ("debian11", [])
+            # This is to address Apple clang defaults C++98.
+            cmake_args = (
+                ["-DCMAKE_CXX_STANDARD=14"]
+                if platform_string() == "mac"
+                else []
+            )
+            return ("debian11", cmake_args)
         elif compiler == "gcc8":
             return ("gcc_8", [])
         elif compiler == "gcc10.2":
@@ -1777,7 +1783,7 @@ argp.add_argument(
 argp.add_argument(
     "--cmake_configure_extra_args",
     default=[],
-    nargs="+",
+    action="append",
     help="Extra arguments that will be passed to the cmake configure command. Only works for C/C++.",
 )
 args = argp.parse_args()