Trim packages when running in a workspace. (#4278)

* Trim packages when running in a workspace.

* Address review comments.

Author: davidmorgan

build_runner/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 - Bug fix: fix crash when you run `dart run build_runner build` in a
   subdirectory of a package.
+- Bug fix: in a workspace, generate for transitive dependencies of the current
+  package instead of for all packages in the workspace.
 
 ## 2.10.2
 

build_runner/lib/src/build_plan/package_graph.dart

@@ -155,7 +155,31 @@ class PackageGraph implements AssetPathProvider {
         ),
       );
     }
-    return PackageGraph._(rootNode, nodes);
+
+    // A workspace can have packages that are not depended on by [rootPackage].
+    // Compute transitive dependencies and filter to that.
+    Set<PackageNode>? usedNodes;
+    if (workspacePath != null) {
+      usedNodes = {rootNode};
+      final queue = [rootNode];
+      while (queue.isNotEmpty) {
+        final node = queue.removeLast();
+        for (final dep in node.dependencies) {
+          if (usedNodes.add(dep)) {
+            queue.add(dep);
+          }
+        }
+      }
+    }
+
+    return PackageGraph._(
+      rootNode,
+      usedNodes == null
+          ? nodes
+          : Map.fromEntries(
+            nodes.entries.where((e) => usedNodes!.contains(e.value)),
+          ),
+    );
   }
 
   /// Creates a [PackageGraph] for the package in which you are currently

build_runner/test/build_plan/package_graph_test.dart

@@ -192,7 +192,7 @@ void main() {
   group('workspace ', () {
     final workspaceFixturePath = p.absolute('test/fixtures/workspace');
 
-    test('Loads all packages in workspace. Has correct root', () async {
+    test('loads only dependent packages, has correct root', () async {
       Matcher packageNodeEquals(PackageNode node) => isA<PackageNode>()
           .having((c) => c.path, 'path', node.path)
           .having(
@@ -223,17 +223,10 @@ void main() {
         null,
       );
       a.dependencies.add(b);
-      final workspace = PackageNode(
-        'workspace',
-        workspaceFixturePath,
-        DependencyType.path,
-        null,
-      );
 
       expect(graph.allPackages, {
         'a': packageNodeEquals(a),
         'b': packageNodeEquals(b),
-        'workspace': packageNodeEquals(workspace),
         r'$sdk': anything,
       });
 

build_runner/test/common/build_runner_tester.dart

@@ -43,6 +43,8 @@ class BuildRunnerTester {
     required Map<String, String> files,
     List<String>? dependencies,
     List<String>? pathDependencies,
+    List<String>? workspaceDependencies,
+    bool inWorkspace = false,
   }) {
     _writeDirectory(
       name: name,
@@ -51,6 +53,8 @@ class BuildRunnerTester {
           name: name,
           dependencies: dependencies,
           pathDependencies: pathDependencies,
+          workspaceDependencies: workspaceDependencies,
+          inWorkspace: inWorkspace,
         ),
         ...files,
       },
@@ -410,22 +414,35 @@ class Pubspecs {
   /// The specified [pathDependencies] are included as path dependencies onto
   /// peer folders. This allows to add a dependency onto another package that
   /// will be written using `writePackage`.
+  ///
+  /// The specified [workspaceDependencies] are included as "any" dependencies.
+  /// They should be in the workspace so they can be resolved from there.
+  ///
+  /// If [inWorkspace] then `resolution: workspace`.
   String pubspec({
     required String name,
     List<String>? dependencies,
     List<String>? pathDependencies,
+    List<String>? workspaceDependencies,
+    bool inWorkspace = false,
   }) {
     dependencies ??= [];
     pathDependencies ??= [];
+    workspaceDependencies ??= [];
 
     final result = StringBuffer('''
 name: $name
+${inWorkspace ? 'resolution: workspace' : ''}
 environment:
   sdk: '>=3.7.0 <4.0.0'
 dependencies:
 ''');
 
-    for (final package in [...dependencies, ...pathDependencies]) {
+    for (final package in [
+      ...dependencies,
+      ...pathDependencies,
+      ...workspaceDependencies,
+    ]) {
       result.writeln('  $package: any');
     }
 

build_runner/test/integration_tests/build_command_packages_and_paths_test.dart

@@ -20,14 +20,84 @@ void main() async {
     tester.writePackage(
       name: 'root_pkg',
       dependencies: ['build_runner'],
-      pathDependencies: ['builder_pkg'],
+      pathDependencies: ['builder_pkg', 'other_pkg'],
       files: {'lib/a.txt': 'a'},
     );
+    tester.writePackage(name: 'other_pkg', files: {'lib/b.txt': 'b'});
 
     // Runs in a subdirectory of the package.
     await tester.run('root_pkg/lib', 'dart run build_runner build');
     expect(tester.readFileTree('root_pkg/.dart_tool/build/generated'), {
       'root_pkg/lib/a.txt.copy': 'a',
+      'other_pkg/lib/b.txt.copy': 'b',
+    });
+
+    // Remove dep on `other_package`, no longer generated.
+    tester.writePackage(
+      name: 'root_pkg',
+      dependencies: ['build_runner'],
+      pathDependencies: ['builder_pkg'],
+      files: {'lib/a.txt': 'a'},
+    );
+    _deletePubspecs(tester);
+    await tester.run('root_pkg/lib', 'dart run build_runner build');
+    expect(tester.readFileTree('root_pkg/.dart_tool/build/generated'), {
+      'root_pkg/lib/a.txt.copy': 'a',
+    });
+
+    // Change to a workspace, still no dep onto `other_pkg`.
+    tester.writePackage(
+      name: 'root_pkg',
+      dependencies: ['build_runner'],
+      pathDependencies: ['builder_pkg'],
+      files: {'lib/a.txt': 'a'},
+      inWorkspace: true,
+    );
+    tester.writePackage(
+      name: 'other_pkg',
+      files: {'lib/b.txt': 'b'},
+      inWorkspace: true,
+    );
+    tester.write('pubspec.yaml', '''
+name: workspace
+environment:
+  sdk: ^3.5.0
+workspace:
+  - root_pkg
+  - other_pkg
+''');
+
+    // Files still not generated for `other_pkg` as it's not a dep.
+    _deletePubspecs(tester);
+    await tester.run('root_pkg/lib', 'dart run build_runner build');
+    expect(tester.readFileTree('root_pkg/.dart_tool/build/generated'), {
+      'root_pkg/lib/a.txt.copy': 'a',
+    });
+
+    // Add dep onto `other_pkg`.
+    tester.writePackage(
+      name: 'root_pkg',
+      dependencies: ['build_runner'],
+      pathDependencies: ['builder_pkg'],
+      workspaceDependencies: ['other_pkg'],
+      files: {'lib/a.txt': 'a'},
+      inWorkspace: true,
+    );
+
+    // Files generated for `other_pkg` now it's a dep.
+    _deletePubspecs(tester);
+    await tester.run('root_pkg/lib', 'dart run build_runner build');
+    expect(tester.readFileTree('root_pkg/.dart_tool/build/generated'), {
+      'root_pkg/lib/a.txt.copy': 'a',
+      'other_pkg/lib/b.txt.copy': 'b',
     });
   });
 }
+
+// Work around "dart run" issue https://github.com/dart-lang/sdk/issues/61950.
+void _deletePubspecs(BuildRunnerTester tester) {
+  if (tester.read('pubspec.lock') != null) tester.delete('pubspec.lock');
+  if (tester.read('root_pkg/pubspec.lock') != null) {
+    tester.delete('root_pkg/pubspec.lock');
+  }
+}