pkg/analysis_server/integration_test/support/plugin_mixin.dart

// Copyright (c) 2026, 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 'dart:convert';
import 'dart:io';
import 'dart:isolate';

import '../lsp_server/integration_tests.dart';

/// A mixin that can create simple plugins that use
/// 'package:analysis_server_plugin' for use in integration tests.
mixin PluginMixin on AbstractLspAnalysisServerIntegrationTest {
  late var pluginsFolderPath = Directory.systemTemp
      .createTempSync('analysisServer_test_integration_plugins')
      .resolveSymbolicLinksSync();

  /// A simple plugin that always produces a diagnostic at 0:0 for every file
  /// that is analyzed.
  late final alwaysProduceDiagnosticPlugin = TestPlugin(
    'always_produce_diagnostic',
    _createPluginSourceCode(
      className: 'AlwaysProduceDiagnostic',
      ruleBody: 'rule.reportAtOffset(0, 0);',
    ),
  );

  /// A simple plugin that throws in its constructor.
  late final throwInConstructorPlugin = TestPlugin(
    'throw_in_constructor',
    _createPluginSourceCode(
      className: 'ThrowInConstructor',
      ruleBody: '',
      constructorBody: 'throw UnimplementedError();',
    ),
  );

  /// A simple plugin that throws an exception asynchronously.
  late final throwAsynchronouslyPlugin = TestPlugin(
    'throw_async',
    _createPluginSourceCode(
      className: 'ThrowAsync',
      ruleBody: 'Future.value().then(() => throw UnimplementedError());',
    ),
  );

  /// A simple plugin that throws during analysis.
  late final throwDuringAnalysisPlugin = TestPlugin(
    'throw_during_analysis',
    _createPluginSourceCode(
      className: 'ThrowDuringAnalysis',
      ruleBody: 'throw UnimplementedError();',
    ),
  );

  void createPlugins(List<TestPlugin> plugins) {
    var analysisOptionsContent = StringBuffer()..writeln('plugins:');
    for (var plugin in plugins) {
      var name = plugin.name;
      var pluginPath = _createPlugin(plugin);
      analysisOptionsContent
        ..writeln('  $name:')
        ..writeln('    path: ${jsonEncode(pluginPath)}');
    }

    // Override paths to the plugin packages to use them from the SDK instead
    // of trying to pull them from Pub when the plugins are started.
    // `PluginPackageGenerator.generatePubspec` may contain a version matching
    // the local code that has not been pushed to Pub.
    var packages = [
      '_fe_analyzer_shared',
      'analysis_server_plugin',
      'analyzer_plugin',
      'analyzer',
    ];
    analysisOptionsContent.writeln('  dependency_overrides:');
    for (var package in packages) {
      var packagePath = _getSdkSourcePackagePath(package);
      analysisOptionsContent.writeln('''
    $package:
      path: ${jsonEncode(packagePath)}
''');
    }

    newFile(analysisOptionsPath, analysisOptionsContent.toString());
  }

  @override
  Future<void> tearDown() async {
    await super.tearDown();
    Directory(pluginsFolderPath).deleteSync(recursive: true);
  }

  /// Creates a plugin in the temporary directory and returns its path.
  String _createPlugin(TestPlugin plugin) {
    var name = plugin.name;
    var sourceCode = plugin.sourceCode;

    var pluginPath = pathContext.join(pluginsFolderPath, name);
    var libFolder = pathContext.join(pluginPath, 'lib');

    newFolder(pluginPath);
    newFolder(libFolder);
    newFile(pathContext.join(libFolder, 'main.dart'), sourceCode);
    newFile(pathContext.join(pluginPath, 'pubspec.yaml'), '''
name: $name
description: A simple plugin.
version: 1.0.0

environment:
  sdk: ^3.12.0
''');

    return pluginPath;
  }

  /// Creates the source for a simple plugin.
  String _createPluginSourceCode({
    required String className,
    String code = 'my_diagnostic',
    String diagnosticMessage = 'A diagnostic generated by a plugin.',
    String ruleName = 'my_diagnostic_rule',
    String ruleDescription = 'A diagnostic rule',
    required String ruleBody,
    String constructorBody = '',
  }) {
    return '''
import 'package:analysis_server_plugin/plugin.dart';
import 'package:analysis_server_plugin/registry.dart';
import 'package:analyzer/analysis_rule/analysis_rule.dart';
import 'package:analyzer/analysis_rule/rule_context.dart';
import 'package:analyzer/analysis_rule/rule_visitor_registry.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/ast/visitor.dart';
import 'package:analyzer/error/error.dart';

final plugin = ${className}Plugin();

class ${className}Plugin extends Plugin {
  @override
  String get name => 'plugin: $className';

  ${className}Plugin() {
    $constructorBody
  }

  @override
  void register(PluginRegistry registry) {
    registry.registerWarningRule(${className}Rule());
  }
}

class ${className}Rule extends AnalysisRule {
  static const LintCode code = LintCode('$code', ${jsonEncode(diagnosticMessage)});

  ${className}Rule()
    : super(
        name: '$ruleName',
        description: ${jsonEncode(ruleDescription)},
      );

  @override
  LintCode get diagnosticCode => code;

  @override
  void registerNodeProcessors(
    RuleVisitorRegistry registry,
    RuleContext context,
  ) {
    var visitor = _${className}Visitor(this);
    registry.addCompilationUnit(this, visitor);
  }
}

class _${className}Visitor extends SimpleAstVisitor<void> {
  final AnalysisRule rule;

  _${className}Visitor(this.rule);

  @override
  void visitCompilationUnit(CompilationUnit node) {
    $ruleBody
  }
}
''';
  }

  /// Gets the source path to [package] in the local SDK checkout.
  ///
  /// This is used for dependency overrides for plugins so that they run using
  /// the local source code and not pulled from Pub.
  String _getSdkSourcePackagePath(String package) {
    var libFolderUri = Isolate.resolvePackageUriSync(
      Uri.parse('package:$package/'),
    );
    var rootFolderPath = pathContext.normalize(
      pathContext.join(libFolderUri!.toFilePath(), '..'),
    );
    return rootFolderPath;
  }
}

class TestPlugin {
  final String name;
  final String sourceCode;

  new(this.name, this.sourceCode);
}