Fix compilation with DDC (#516)

b272632450 exposed client certificate through 
`X509Certificate? get clientCertificate;` getter on `ServiceCall` class. This broke 
compilation of `grpc_web` code using DDC, but not dart2js. Turns out that dart2js is 
happy to compile any code using `dart:io` (though the result will not run if you try
to use any of those APIs), but DDC rejects such code eagerly. `package:test` runs 
tests through `dart2js` so DDC breakage was not really caught by CI. 

Unfortunately this discrepancy between DDC and dart2js puts us in some really weird 
spot: most of our tests are platform independent, but most of those tests also 
pull in `dart:io` through transitive dependencies.

This commit is the most minimal change we could make to allow the code compile both 
on the Web and natively. 

A proper fix should be to go through tests one-by-one and make sure that those that
need to run on the Web don't import `dart:io`, but we don't have time to do that 
right now. 

This commit also adds a smoke test to the CI to verify that `grpc_web` example 
builds with DDC.

.github/workflows/dart.yml

@@ -19,14 +19,15 @@ jobs:
         sdk: [dev, 2.12.0]
     steps:
       - uses: actions/checkout@v2
-      - uses: dart-lang/setup-dart@v1.0
+      - uses: dart-lang/setup-dart@v1.2
         with:
           sdk: ${{ matrix.sdk }}
       - name: Report version
         run: dart --version
       - name: Install dependencies
         run: dart pub get
-      - name: Check formatting
+      - name: Check formatting (using dev dartfmt release)
+        if: ${{ matrix.sdk == 'dev' }}
         run: dart format --output=none --set-exit-if-changed .
       - name: Analyze code (introp and examples)
         run: |
@@ -39,6 +40,16 @@ jobs:
         shell: bash
       - name: Analyze code
         run: dart analyze --fatal-infos .
+      - name: Check that grpc-web sample builds with DDC
+        if: ${{ matrix.sdk == 'dev' }}
+        # webdev build --no-release to force compilation with DDC.
+        run: |
+          dart pub global activate webdev
+          pushd example/grpc-web
+          rm -rf build
+          dart pub global run webdev build --no-release
+          test -f ./build/main.dart.js
+          popd
 
   # Run tests on a matrix consisting of three dimensions:
   # 1. OS: mac, windows, linux
@@ -61,7 +72,7 @@ jobs:
             platform: chrome
     steps:
       - uses: actions/checkout@v2
-      - uses: dart-lang/setup-dart@v1.0
+      - uses: dart-lang/setup-dart@v1.2
         with:
           sdk: ${{ matrix.sdk }}
       - name: Report version

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 3.0.2
+
+* Fix compilation on the Web with DDC.
+
 ## 3.0.1
 
 * Require `package:googleapis_auth` `^1.1.0`

lib/src/server/call.dart

@@ -13,7 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import 'dart:io';
+import '../shared/io_bits/io_bits.dart' show X509Certificate;
 
 /// Server-side context for a gRPC call.
 ///

lib/src/server/handler.dart

@@ -15,12 +15,12 @@
 
 import 'dart:async';
 import 'dart:convert';
-import 'dart:io';
 
 import 'package:http2/transport.dart';
 
 import '../shared/codec.dart';
 import '../shared/codec_registry.dart';
+import '../shared/io_bits/io_bits.dart' show X509Certificate;
 import '../shared/message.dart';
 import '../shared/status.dart';
 import '../shared/streams.dart';

lib/src/server/server.dart

@@ -20,6 +20,7 @@ import 'package:http2/transport.dart';
 import 'package:meta/meta.dart';
 
 import '../shared/codec_registry.dart';
+import '../shared/io_bits/io_bits.dart' as io_bits;
 import '../shared/security.dart';
 import 'handler.dart';
 import 'interceptor.dart';
@@ -129,8 +130,10 @@ class ConnectionServer {
   ServerHandler_ serveStream_(ServerTransportStream stream,
       [X509Certificate? clientCertificate]) {
     return ServerHandler_(
-        lookupService, stream, _interceptors, _codecRegistry, clientCertificate)
-      ..handle();
+      lookupService, stream, _interceptors, _codecRegistry,
+      // ignore: unnecessary_cast
+      clientCertificate as io_bits.X509Certificate?,
+    )..handle();
   }
 }
 
@@ -223,8 +226,13 @@ class Server extends ConnectionServer {
   ServerHandler_ serveStream_(ServerTransportStream stream,
       [X509Certificate? clientCertificate]) {
     return ServerHandler_(
-        lookupService, stream, _interceptors, _codecRegistry, clientCertificate)
-      ..handle();
+      lookupService,
+      stream,
+      _interceptors,
+      _codecRegistry,
+      // ignore: unnecessary_cast
+      clientCertificate as io_bits.X509Certificate?,
+    )..handle();
   }
 
   @Deprecated(

lib/src/shared/io_bits/io_bits.dart

@@ -0,0 +1,16 @@
+// Copyright (c) 2021, the gRPC project authors. Please see the AUTHORS file
+// for details. 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.
+
+export 'io_bits_io.dart' if (dart.library.html) 'io_bits_web.dart';

lib/src/shared/io_bits/io_bits_io.dart

@@ -0,0 +1,16 @@
+// Copyright (c) 2021, the gRPC project authors. Please see the AUTHORS file
+// for details. 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.
+
+export 'dart:io' show HttpStatus, X509Certificate;

lib/src/shared/io_bits/io_bits_web.dart

@@ -0,0 +1,20 @@
+// Copyright (c) 2021, the gRPC project authors. Please see the AUTHORS file
+// for details. 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.
+
+export 'dart:html' show HttpStatus;
+
+/// Should not be used on the Web, but is pulled through [ServiceCall] class
+/// which is used in the protoc generated code.
+class X509Certificate {}

lib/src/shared/status.dart

@@ -14,7 +14,6 @@
 // limitations under the License.
 
 import 'dart:convert';
-import 'dart:io' show HttpStatus;
 
 import 'package:meta/meta.dart';
 import 'package:protobuf/protobuf.dart';
@@ -23,6 +22,7 @@ import '../generated/google/protobuf/any.pb.dart';
 import '../generated/google/rpc/code.pbenum.dart';
 import '../generated/google/rpc/error_details.pb.dart';
 import '../generated/google/rpc/status.pb.dart';
+import 'io_bits/io_bits.dart' show HttpStatus;
 
 class StatusCode {
   /// The operation completed successfully.

pubspec.yaml

@@ -1,7 +1,7 @@
 name: grpc
 description: Dart implementation of gRPC, a high performance, open-source universal RPC framework.
 
-version: 3.0.1
+version: 3.0.2
 
 repository: https://github.com/grpc/grpc-dart