Add protocopt option to protoc go compiler

.bazelrc

@@ -10,3 +10,6 @@ build:ci --spawn_strategy=standalone
 build:ci --genrule_strategy=standalone
 test:ci --test_strategy=standalone
 test:ci --test_output=errors
+
+# Required for proto related tests.
+build --protocopt=--experimental_allow_proto3_optional

WORKSPACE

@@ -10,12 +10,12 @@ go_register_toolchains(version = "1.16rc1")
 
 http_archive(
     name = "com_google_protobuf",
-    sha256 = "a79d19dcdf9139fa4b81206e318e33d245c4c9da1ffed21c87288ed4380426f9",
-    strip_prefix = "protobuf-3.11.4",
-    # latest, as of 2020-02-21
+    sha256 = "d0f5f605d0d656007ce6c8b5a82df3037e1d8fe8b121ed42e536f569dec16113",
+    strip_prefix = "protobuf-3.14.0",
+    # latest, as of 2020-11-13
     urls = [
-        "https://mirror.bazel.build/github.com/protocolbuffers/protobuf/archive/v3.11.4.tar.gz",
-        "https://github.com/protocolbuffers/protobuf/archive/v3.11.4.tar.gz",
+        "https://mirror.bazel.build/github.com/protocolbuffers/protobuf/archive/v3.14.0.tar.gz",
+        "https://github.com/protocolbuffers/protobuf/archive/v3.14.0.tar.gz",
     ],
 )
 

go/tools/builders/protoc.go

@@ -49,6 +49,7 @@ func run(args []string) error {
 	descriptors := multiFlag{}
 	expected := multiFlag{}
 	imports := multiFlag{}
+	protocopts := multiFlag{}
 	flags := flag.NewFlagSet("protoc", flag.ExitOnError)
 	protoc := flags.String("protoc", "", "The path to the real protoc.")
 	outPath := flags.String("out_path", "", "The base output path to write to.")
@@ -58,6 +59,7 @@ func run(args []string) error {
 	flags.Var(&descriptors, "descriptor_set", "The descriptor set to read.")
 	flags.Var(&expected, "expected", "The expected output files.")
 	flags.Var(&imports, "import", "Map a proto file to an import path.")
+	flags.Var(&protocopts, "protocopt", "Extra options to pass to protoc.")
 	if err := flags.Parse(args); err != nil {
 		return err
 	}
@@ -88,7 +90,9 @@ func run(args []string) error {
 		"--plugin", fmt.Sprintf("%v=%v", strings.TrimSuffix(pluginBase, ".exe"), *plugin),
 		"--descriptor_set_in", strings.Join(descriptors, string(os.PathListSeparator)),
 	}
+	protoc_args = append(protoc_args, protocopts...)
 	protoc_args = append(protoc_args, flags.Args()...)
+
 	cmd := exec.Command(*protoc, protoc_args...)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr

proto/compiler.bzl

@@ -99,6 +99,7 @@ def go_proto_compile(go, compiler, protos, imports, importpath):
     args.add("-importpath", importpath)
     args.add("-out_path", outpath)
     args.add("-plugin", compiler.internal.plugin)
+    args.add_all("-protocopt", compiler.internal.protocopts)
 
     # TODO(jayconrod): can we just use go.env instead?
     args.add_all(compiler.internal.options, before_each = "-option")
@@ -190,6 +191,7 @@ def _go_proto_compiler_impl(ctx):
                 go_protoc = ctx.file._go_protoc,
                 plugin = ctx.file.plugin,
                 import_path_option = ctx.attr.import_path_option,
+                protocopts = ctx.attr.protocopts,
             ),
         ),
         library,
@@ -209,6 +211,7 @@ _go_proto_compiler = rule(
             cfg = "exec",
             mandatory = True,
         ),
+        "protocopts": attr.string_list(),
         "_go_protoc": attr.label(
             allow_single_file = True,
             cfg = "exec",

tests/core/go_proto_library/BUILD.bazel

@@ -1,6 +1,13 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
 load("@rules_proto//proto:defs.bzl", "proto_library")
+load("@io_bazel_rules_go//proto:compiler.bzl", "go_proto_compiler")
+load(
+    "//proto/wkt:well_known_types.bzl",
+    "PROTO_RUNTIME_DEPS",
+    "WELL_KNOWN_TYPES_APIV2",
+    "WELL_KNOWN_TYPE_RULES",
+)
 
 # Common rules
 proto_library(
@@ -312,3 +319,27 @@ go_test(
         "@org_golang_google_protobuf//types/pluginpb:go_default_library",
     ],
 )
+
+go_proto_compiler(
+    name = "proto_optionals_compiler",
+    protocopts = ["--experimental_allow_proto3_optional"], 
+    deps = PROTO_RUNTIME_DEPS + WELL_KNOWN_TYPE_RULES.values() + WELL_KNOWN_TYPES_APIV2,
+)
+
+proto_library(
+    name = "proto_optionals",
+    srcs = ["proto_optionals.proto"],
+)
+
+go_proto_library(
+    name = "go_proto_optionals",
+    compilers = [":proto_optionals_compiler"],
+    protos = [":proto_optionals"],
+    importpath = "github.com/bazelbuild/rules_go/tests/core/go_proto_library/protos",
+)
+
+go_test(
+    name = "proto_optionals_test",
+    srcs = ["proto_optionals_test.go"],
+    deps = [":go_proto_optionals"],
+)

tests/core/go_proto_library/README.rst

@@ -59,3 +59,8 @@ protos_alias_test
 
 Checks that packages generated by `go_proto_library` can be imported using one of the strings
 listed in ``importpath_aliases``.
+
+proto_optionals_test
+--------------------
+
+Checks that protocopts can be provided via go_proto_compiler.

tests/core/go_proto_library/proto_optionals.proto

@@ -0,0 +1,9 @@
+syntax = "proto3";
+
+option go_package = "github.com/bazelbuild/rules_go/tests/core/go_proto_library/protos";
+
+message Foo {
+    // Experimental protoc feature
+    // See: https://github.com/protocolbuffers/protobuf/blob/master/docs/implementing_proto3_presence.md
+    optional int64 x = 1; 
+}

tests/core/go_proto_library/proto_optionals_test.go

@@ -0,0 +1,27 @@
+/* Copyright 2019 The Bazel Authors. All rights reserved.
+
+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.
+*/
+
+package proto_optionals_test
+
+import (
+	"testing"
+
+	"github.com/bazelbuild/rules_go/tests/core/go_proto_library/protos"
+)
+
+func TestProtoOptional(t *testing.T) {
+	x := int64(1)
+	_ = protos.Foo{X: &x} // X is a pointer to int64 since it is proto3 optional.
+}