Add protobuf pod version sanitizer

tools/distrib/check_protobuf_pod_version.sh

@@ -0,0 +1,46 @@
+#!/bin/bash
+# Copyright 2019 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -ex
+
+cd `dirname $0`/../..
+
+# get the version of protobuf in /third_party/protobuf
+pushd third_party/protobuf
+
+version1=$(git describe --tags | cut -f 1 -d'-')
+v1=${version1:1}
+
+popd
+
+# get the version of protobuf in /src/objective-c/!ProtoCompiler.podspec
+v2=$(cat src/objective-c/\!ProtoCompiler.podspec | egrep "v = " | cut -f 2 -d"'")
+
+# get the version of protobuf in /src/objective-c/!ProtoCompiler-gRPCPlugin.podspec
+v3=$(cat src/objective-c/\!ProtoCompiler-gRPCPlugin.podspec | egrep 'dependency.*!ProtoCompiler' | cut -f 4 -d"'")
+
+# compare and emit error
+ret=0
+if [ $v1 != $v2 ]; then
+  echo 'Protobuf version in src/objective-c/!ProtoCompiler.podspec does not match protobuf version in third_party/protobuf.'
+  ret=1
+fi
+
+if [ $v1 != $v3 ]; then
+  echo 'Protobuf version in src/objective-c/!ProtoCompiler-gRPCPlugin.podspec does not match protobuf version in third_party/protobuf.'
+  ret=1
+fi
+  
+exit $ret

tools/run_tests/sanity/sanity_tests.yaml

@@ -24,4 +24,5 @@
 - script: tools/distrib/yapf_code.sh
 - script: tools/distrib/python/check_grpcio_tools.py
 - script: tools/distrib/check_shadow_boringssl_symbol_list.sh
+- script: tools/distrib/check_protobuf_pod_version.sh
   cpu_cost: 1000