cmd/protoc-gen-go-grpc: add change detector test

.github/workflows/testing.yml

@@ -36,9 +36,6 @@ jobs:
 
   # Run the main gRPC-Go tests.
   tests:
-    # Proto checks are run in the above job.
-    env:
-      VET_SKIP_PROTO: 1
     runs-on: ubuntu-latest
     timeout-minutes: 20
     strategy:
@@ -98,7 +95,7 @@ jobs:
       # Only run vet for 'vet' runs.
       - name: Run vet.sh
         if: matrix.type == 'vet'
-        run: ./vet.sh -install && ./vet.sh
+        run: export VET_SKIP_PROTO=1 && ./vet.sh -install && ./vet.sh
 
       # Main tests run for everything except when testing "extras"
       # (where we run a reduced set of tests).
@@ -128,3 +125,6 @@ jobs:
           interop/interop_test.sh
           echo -e "\n-- Running xDS E2E Test --"
           xds/internal/test/e2e/run.sh
+          echo -e "\n-- Running protoc-gen-go-grpc test --"
+          ./vet.sh -install
+          cmd/protoc-gen-go-grpc/protoc-gen-go-grpc_test.sh

cmd/protoc-gen-go-grpc/README.md

@@ -13,7 +13,7 @@ change from the grpc code generator previously included with `protoc-gen-go`.
 To restore this behavior, set the option `require_unimplemented_servers=false`.
 E.g.:
 
-```
+```sh
   protoc --go-grpc_out=. --go-grpc_opt=require_unimplemented_servers=false[,other options...] \
 ```
 

cmd/protoc-gen-go-grpc/proto/golden.proto

@@ -0,0 +1,34 @@
+// Copyright 2024 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.
+
+syntax = "proto3";
+
+option go_package = "testdata/proto";
+
+package main;
+
+message EventRequest {
+  bytes content = 1;
+}
+
+message EventResponse {
+  bytes content = 1;
+}
+
+service BidirectionalStreamingService {
+  rpc unaryMethod(EventRequest) returns (EventResponse) {}
+  rpc clientMethod(stream EventRequest) returns (EventResponse) {}
+  rpc serverMethod(EventRequest) returns (stream EventResponse) {};
+  rpc bidirectionalMethod(stream EventRequest) returns (stream EventResponse) {}
+}

cmd/protoc-gen-go-grpc/protoc-gen-go-grpc_test.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+set -ex # Debugging enabled.
+
+trap "git clean --force --quiet" EXIT
+
+WD="$(dirname $0)"
+
+# Build protoc-gen-go-grpc binary and add to $PATH.
+pushd "${WD}"
+go build .
+PATH="${WD}:${PATH}"
+popd
+
+protoc \
+    --go-grpc_out=. \
+    --go-grpc_opt=paths=source_relative \
+    "$WD/proto/golden.proto"
+
+if !(diff -u "${WD}/testdata/golden_grpc.pb.go" "${WD}/proto/golden_grpc.pb.go"); then
+    echo "Generated file golden_grpc.pb.go differs from golden file; If you have made recent changes to protoc-gen-go-grpc, please regenerate the golden files." >&2
+    exit 1
+fi
+
+echo SUCCESS