Support null safety (#740)

Fixes #712

Author: kevmoo

.github/workflows/dart.yml

@@ -36,16 +36,16 @@ jobs:
       - run: pub global activate mono_repo 3.3.0
       - run: pub global run mono_repo generate --validate
   job_002:
-    name: "OS: linux; SDK: dev; PKGS: _test_yaml, checked_yaml, example, json_annotation, json_serializable; TASKS: [`dartfmt -n --set-exit-if-changed .`, `dartanalyzer --fatal-warnings --fatal-infos .`]"
+    name: "OS: linux; SDK: dev; PKGS: _test_yaml, checked_yaml, json_annotation, json_serializable; TASKS: [`dartfmt -n --set-exit-if-changed .`, `dartanalyzer --fatal-warnings --fatal-infos .`]"
     runs-on: ubuntu-latest
     steps:
       - name: Cache Pub hosted dependencies
         uses: actions/cache@v2
         with:
           path: "~/.pub-cache/hosted"
-          key: "os:ubuntu-latest;pub-cache-hosted;dart:dev;packages:_test_yaml-checked_yaml-example-json_annotation-json_serializable;commands:dartfmt-dartanalyzer_0"
+          key: "os:ubuntu-latest;pub-cache-hosted;dart:dev;packages:_test_yaml-checked_yaml-json_annotation-json_serializable;commands:dartfmt-dartanalyzer_0"
           restore-keys: |
-            os:ubuntu-latest;pub-cache-hosted;dart:dev;packages:_test_yaml-checked_yaml-example-json_annotation-json_serializable
+            os:ubuntu-latest;pub-cache-hosted;dart:dev;packages:_test_yaml-checked_yaml-json_annotation-json_serializable
             os:ubuntu-latest;pub-cache-hosted;dart:dev
             os:ubuntu-latest;pub-cache-hosted
             os:ubuntu-latest
@@ -55,20 +55,20 @@ jobs:
       - run: dart --version
       - uses: actions/checkout@v2
       - env:
-          PKGS: _test_yaml checked_yaml example json_annotation json_serializable
+          PKGS: _test_yaml checked_yaml json_annotation json_serializable
           TRAVIS_OS_NAME: linux
         run: tool/ci.sh dartfmt dartanalyzer_0
-  job_003:
-    name: "OS: linux; SDK: 2.7.0; PKGS: _test_yaml, checked_yaml, example, json_annotation, json_serializable; TASKS: `dartanalyzer --fatal-warnings .`"
+  job_005:
+    name: "OS: linux; SDK: 2.7.0; PKG: checked_yaml; TASKS: `dartanalyzer --fatal-warnings .`"
     runs-on: ubuntu-latest
     steps:
       - name: Cache Pub hosted dependencies
         uses: actions/cache@v2
         with:
           path: "~/.pub-cache/hosted"
-          key: "os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:_test_yaml-checked_yaml-example-json_annotation-json_serializable;commands:dartanalyzer_1"
+          key: "os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:checked_yaml;commands:dartanalyzer_1"
           restore-keys: |
-            os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:_test_yaml-checked_yaml-example-json_annotation-json_serializable
+            os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:checked_yaml
             os:ubuntu-latest;pub-cache-hosted;dart:2.7.0
             os:ubuntu-latest;pub-cache-hosted
             os:ubuntu-latest
@@ -79,38 +79,33 @@ jobs:
       - run: dart --version
       - uses: actions/checkout@v2
       - env:
-          PKGS: _test_yaml checked_yaml example json_annotation json_serializable
+          PKGS: checked_yaml
           TRAVIS_OS_NAME: linux
         run: tool/ci.sh dartanalyzer_1
-  job_004:
-    name: "OS: linux; SDK: 2.7.0; PKGS: _test_yaml, checked_yaml, example, json_serializable; TASKS: `pub run test`"
+  job_008:
+    name: "OS: linux; SDK: dev; PKG: example; TASKS: [`dartfmt -n --set-exit-if-changed .`, `dartanalyzer --fatal-warnings .`]"
     runs-on: ubuntu-latest
     steps:
       - name: Cache Pub hosted dependencies
         uses: actions/cache@v2
         with:
           path: "~/.pub-cache/hosted"
-          key: "os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:_test_yaml-checked_yaml-example-json_serializable;commands:test_0"
+          key: "os:ubuntu-latest;pub-cache-hosted;dart:dev;packages:example;commands:dartfmt-dartanalyzer_1"
           restore-keys: |
-            os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:_test_yaml-checked_yaml-example-json_serializable
-            os:ubuntu-latest;pub-cache-hosted;dart:2.7.0
+            os:ubuntu-latest;pub-cache-hosted;dart:dev;packages:example
+            os:ubuntu-latest;pub-cache-hosted;dart:dev
             os:ubuntu-latest;pub-cache-hosted
             os:ubuntu-latest
       - uses: cedx/setup-dart@v2
         with:
-          release-channel: stable
-          version: "2.7.0"
+          release-channel: dev
       - run: dart --version
       - uses: actions/checkout@v2
       - env:
-          PKGS: _test_yaml checked_yaml example json_serializable
+          PKGS: example
           TRAVIS_OS_NAME: linux
-        run: tool/ci.sh test_0
-    needs:
-      - job_001
-      - job_002
-      - job_003
-  job_005:
+        run: tool/ci.sh dartfmt dartanalyzer_1
+  job_003:
     name: "OS: linux; SDK: dev; PKGS: _test_yaml, checked_yaml, example, json_serializable; TASKS: `pub run test`"
     runs-on: ubuntu-latest
     steps:
@@ -136,18 +131,19 @@ jobs:
     needs:
       - job_001
       - job_002
-      - job_003
-  job_008:
-    name: "OS: linux; SDK: 2.7.0; PKG: json_serializable; TASKS: `pub run test -p chrome`"
+      - job_005
+      - job_008
+  job_006:
+    name: "OS: linux; SDK: 2.7.0; PKG: checked_yaml; TASKS: `pub run test`"
     runs-on: ubuntu-latest
     steps:
       - name: Cache Pub hosted dependencies
         uses: actions/cache@v2
         with:
           path: "~/.pub-cache/hosted"
-          key: "os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:json_serializable;commands:test_2"
+          key: "os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:checked_yaml;commands:test_0"
           restore-keys: |
-            os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:json_serializable
+            os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:checked_yaml
             os:ubuntu-latest;pub-cache-hosted;dart:2.7.0
             os:ubuntu-latest;pub-cache-hosted
             os:ubuntu-latest
@@ -158,13 +154,14 @@ jobs:
       - run: dart --version
       - uses: actions/checkout@v2
       - env:
-          PKGS: json_serializable
+          PKGS: checked_yaml
           TRAVIS_OS_NAME: linux
-        run: tool/ci.sh test_2
+        run: tool/ci.sh test_0
     needs:
       - job_001
       - job_002
-      - job_003
+      - job_005
+      - job_008
   job_009:
     name: "OS: linux; SDK: dev; PKG: json_serializable; TASKS: `pub run test -p chrome`"
     runs-on: ubuntu-latest
@@ -191,61 +188,60 @@ jobs:
     needs:
       - job_001
       - job_002
-      - job_003
-  job_006:
-    name: "OS: linux; SDK: 2.7.0; PKGS: _test_yaml, checked_yaml, example, json_serializable; TASKS: `pub run test --run-skipped -t presubmit-only test/ensure_build_test.dart`"
+      - job_005
+      - job_008
+  job_004:
+    name: "OS: linux; SDK: dev; PKGS: _test_yaml, checked_yaml, example, json_serializable; TASKS: `pub run test --run-skipped -t presubmit-only test/ensure_build_test.dart`"
     runs-on: ubuntu-latest
     steps:
       - name: Cache Pub hosted dependencies
         uses: actions/cache@v2
         with:
           path: "~/.pub-cache/hosted"
-          key: "os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:_test_yaml-checked_yaml-example-json_serializable;commands:test_1"
+          key: "os:ubuntu-latest;pub-cache-hosted;dart:dev;packages:_test_yaml-checked_yaml-example-json_serializable;commands:test_1"
           restore-keys: |
-            os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:_test_yaml-checked_yaml-example-json_serializable
-            os:ubuntu-latest;pub-cache-hosted;dart:2.7.0
+            os:ubuntu-latest;pub-cache-hosted;dart:dev;packages:_test_yaml-checked_yaml-example-json_serializable
+            os:ubuntu-latest;pub-cache-hosted;dart:dev
             os:ubuntu-latest;pub-cache-hosted
             os:ubuntu-latest
       - uses: cedx/setup-dart@v2
         with:
-          release-channel: stable
-          version: "2.7.0"
+          release-channel: dev
       - run: dart --version
       - uses: actions/checkout@v2
       - env:
           PKGS: _test_yaml checked_yaml example json_serializable
           TRAVIS_OS_NAME: linux
         run: tool/ci.sh test_1
     needs:
-      - job_004
-      - job_005
-      - job_008
+      - job_003
+      - job_006
       - job_009
   job_007:
-    name: "OS: linux; SDK: dev; PKGS: _test_yaml, checked_yaml, example, json_serializable; TASKS: `pub run test --run-skipped -t presubmit-only test/ensure_build_test.dart`"
+    name: "OS: linux; SDK: 2.7.0; PKG: checked_yaml; TASKS: `pub run test --run-skipped -t presubmit-only test/ensure_build_test.dart`"
     runs-on: ubuntu-latest
     steps:
       - name: Cache Pub hosted dependencies
         uses: actions/cache@v2
         with:
           path: "~/.pub-cache/hosted"
-          key: "os:ubuntu-latest;pub-cache-hosted;dart:dev;packages:_test_yaml-checked_yaml-example-json_serializable;commands:test_1"
+          key: "os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:checked_yaml;commands:test_1"
           restore-keys: |
-            os:ubuntu-latest;pub-cache-hosted;dart:dev;packages:_test_yaml-checked_yaml-example-json_serializable
-            os:ubuntu-latest;pub-cache-hosted;dart:dev
+            os:ubuntu-latest;pub-cache-hosted;dart:2.7.0;packages:checked_yaml
+            os:ubuntu-latest;pub-cache-hosted;dart:2.7.0
             os:ubuntu-latest;pub-cache-hosted
             os:ubuntu-latest
       - uses: cedx/setup-dart@v2
         with:
-          release-channel: dev
+          release-channel: stable
+          version: "2.7.0"
       - run: dart --version
       - uses: actions/checkout@v2
       - env:
-          PKGS: _test_yaml checked_yaml example json_serializable
+          PKGS: checked_yaml
           TRAVIS_OS_NAME: linux
         run: tool/ci.sh test_1
     needs:
-      - job_004
-      - job_005
-      - job_008
+      - job_003
+      - job_006
       - job_009

_test_yaml/mono_pkg.yaml

@@ -1,6 +1,5 @@
 # See https://github.com/google/mono_repo.dart for details on this file
 dart:
-- 2.7.0
 - dev
 
 stages:
@@ -9,9 +8,6 @@ stages:
     - dartfmt
     - dartanalyzer: --fatal-warnings --fatal-infos .
     dart: [dev]
-  - group:
-    - dartanalyzer: --fatal-warnings .
-    dart: [2.7.0]
 - unit_test:
   - test
 - ensure_build:

_test_yaml/pubspec.yaml

@@ -2,7 +2,7 @@ name: _test_yaml
 publish_to: none
 
 environment:
-  sdk: '>=2.7.0 <3.0.0'
+  sdk: '>=2.12.0-0 <3.0.0'
 
 dev_dependencies:
   build_runner: ^1.0.0

_test_yaml/test/ensure_build_test.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart=2.9
+
 @TestOn('vm')
 @Tags(['presubmit-only'])
 import 'package:build_verify/build_verify.dart';

_test_yaml/test/src/build_config.dart

@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:json_annotation/json_annotation.dart';
-import 'package:meta/meta.dart';
 
 part 'build_config.g.dart';
 
@@ -13,9 +12,9 @@ class Config {
   final Map<String, Builder> builders;
 
   // Verifying enum keys in map
-  Map<AutoApply, int> weights;
+  Map<AutoApply, int>? weights;
 
-  Config({@required this.builders});
+  Config({required this.builders});
 
   factory Config.fromJson(Map map) => _$ConfigFromJson(map);
 
@@ -28,49 +27,49 @@ class Config {
     checked: true,
     anyMap: true)
 class Builder {
-  @JsonKey(nullable: true)
-  final String target;
+  final String? target;
 
   final String import;
 
   @JsonKey(name: 'is_optional')
-  final bool isOptional;
+  final bool? isOptional;
 
   @JsonKey(disallowNullValue: true)
-  final Uri configLocation;
+  final Uri? configLocation;
 
   @JsonKey(name: 'auto_apply', disallowNullValue: true)
-  final AutoApply autoApply;
+  final AutoApply? autoApply;
 
   @JsonKey(name: 'build_to')
-  final BuildTo buildTo;
+  final BuildTo? buildTo;
 
-  final AutoApply defaultEnumTest;
+  final AutoApply? defaultEnumTest;
 
-  @JsonKey(name: 'builder_factories', nullable: false)
+  @JsonKey(name: 'builder_factories')
   final List<String> builderFactories;
 
   @JsonKey(name: 'applies_builders')
-  final List<String> appliesBuilders;
+  final List<String>? appliesBuilders;
 
   @JsonKey(name: 'required_inputs')
-  final List<String> requiredInputs;
+  final List<String>? requiredInputs;
 
   @JsonKey(name: 'build_extensions')
-  final Map<String, List<String>> buildExtensions;
-
-  Builder(
-      {@required this.import,
-      this.target,
-      this.isOptional,
-      this.autoApply,
-      this.buildTo,
-      this.defaultEnumTest,
-      this.builderFactories,
-      this.appliesBuilders,
-      this.requiredInputs,
-      this.buildExtensions,
-      this.configLocation}) {
+  final Map<String, List<String>>? buildExtensions;
+
+  Builder({
+    required this.import,
+    this.target,
+    this.isOptional,
+    this.autoApply,
+    this.buildTo,
+    this.defaultEnumTest,
+    required this.builderFactories,
+    this.appliesBuilders,
+    this.requiredInputs,
+    this.buildExtensions,
+    this.configLocation,
+  }) {
     if (builderFactories.isEmpty) {
       throw ArgumentError.value(builderFactories, 'builderFactories',
           'Must have at least one value.');