[native_assets_builder] Fix multiple invocations of the build runner (#103)

Closes #102.

Author: dcharkes

pkgs/native_assets_builder/CHANGELOG.md

@@ -4,6 +4,8 @@
   ([#98](https://github.com/dart-lang/native/issues/98)).
 - Check asset ids on having having a package uri with the owning package
   ([#96](https://github.com/dart-lang/native/issues/96)).
+- `NativeAssetsBuildRunner` can now support multiple calls
+  ([#102](https://github.com/dart-lang/native/issues/102)).
 
 ## 0.1.0
 

pkgs/native_assets_builder/lib/src/build_runner/build_runner.dart

@@ -45,7 +45,7 @@ class NativeAssetsBuildRunner {
     int? targetAndroidNdkApi,
     required bool includeParentEnvironment,
   }) async {
-    assert(_metadata.isEmpty);
+    _metadata.clear();
     final packageLayout =
         await PackageLayout.fromRootPackageRoot(workingDirectory);
     final packagesWithNativeAssets =
@@ -98,7 +98,6 @@ class NativeAssetsBuildRunner {
     required Uri workingDirectory,
     required bool includeParentEnvironment,
   }) async {
-    assert(_metadata.isEmpty);
     final packageLayout =
         await PackageLayout.fromRootPackageRoot(workingDirectory);
     final packagesWithNativeAssets =

pkgs/native_assets_builder/test/build_runner/build_runner_reusability_test.dart

@@ -0,0 +1,59 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// 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.
+
+import 'package:native_assets_builder/src/build_runner/build_runner.dart';
+import 'package:native_assets_cli/native_assets_cli.dart';
+import 'package:test/test.dart';
+
+import '../helpers.dart';
+import 'helpers.dart';
+
+const Timeout longTimeout = Timeout(Duration(minutes: 5));
+
+void main() async {
+  test('multiple dryRun and build invocations', timeout: longTimeout, () async {
+    await inTempDir((tempUri) async {
+      await copyTestProjects(targetUri: tempUri);
+      final packageUri = tempUri.resolve('package_reading_metadata/');
+
+      // First, run `pub get`, we need pub to resolve our dependencies.
+      await runPubGet(
+        workingDirectory: packageUri,
+        logger: logger,
+      );
+
+      final buildRunner = NativeAssetsBuildRunner(
+        logger: logger,
+        dartExecutable: dartExecutable,
+      );
+
+      await buildRunner.dryRun(
+        targetOs: Target.current.os,
+        linkModePreference: LinkModePreference.dynamic,
+        workingDirectory: packageUri,
+        includeParentEnvironment: true,
+      );
+      await buildRunner.dryRun(
+        targetOs: Target.current.os,
+        linkModePreference: LinkModePreference.dynamic,
+        workingDirectory: packageUri,
+        includeParentEnvironment: true,
+      );
+      await buildRunner.build(
+        buildMode: BuildMode.release,
+        linkModePreference: LinkModePreference.dynamic,
+        target: Target.current,
+        workingDirectory: packageUri,
+        includeParentEnvironment: true,
+      );
+      await buildRunner.build(
+        buildMode: BuildMode.release,
+        linkModePreference: LinkModePreference.dynamic,
+        target: Target.current,
+        workingDirectory: packageUri,
+        includeParentEnvironment: true,
+      );
+    });
+  });
+}

pkgs/native_assets_builder/test/data/package_reading_metadata/build.dart

@@ -8,11 +8,15 @@ import 'package:native_assets_cli/native_assets_cli.dart';
 void main(List<String> args) async {
   final config = await Config.fromArgs(args: args);
   final buildConfig = BuildConfig.fromConfig(config);
-  final metadata =
-      buildConfig.dependencyMetadata!['package_with_metadata']!.metadata;
-  final someValue = metadata['some_key'];
-  assert(someValue != null);
-  final someInt = metadata['some_int'];
-  assert(someInt != null);
-  print(metadata);
+  if (!buildConfig.dryRun) {
+    final metadata =
+        buildConfig.dependencyMetadata!['package_with_metadata']!.metadata;
+    final someValue = metadata['some_key'];
+    assert(someValue != null);
+    final someInt = metadata['some_int'];
+    assert(someInt != null);
+    print(metadata);
+  } else {
+    print('meta data not available in dry run');
+  }
 }

pkgs/native_assets_cli/CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 0.1.1-wip
 
 - Added topics.
+- Fixed metadata example.
 
 ## 0.1.0