DAS plugins: Support assists in plugins

To support this feature:

* Remove `DartAssistContextImpl` as it has no differences from
  `DartAssistContext`. Thus the getters `DartAssistContext` are made
  into fields, and all callers now call `DartAssistContext()`.
* Add a top level `computeAssists` function, similar to the top-level
  `computeFixes` function.

Change-Id: I3ef5fd9ee9430150004b29c11ab972939b85b214
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/417360
Reviewed-by: Brian Wilkerson <[email protected]>
Reviewed-by: Phil Quitslund <[email protected]>
Commit-Queue: Samuel Rawlins <[email protected]>

Author: srawlins

pkg/analysis_server/lib/src/cider/assists.dart

@@ -2,8 +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.
 
-import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server_plugin/src/correction/assist_core.dart';
+import 'package:analysis_server_plugin/src/correction/assist_dart.dart';
 import 'package:analysis_server_plugin/src/correction/assist_processor.dart';
 import 'package:analysis_server_plugin/src/correction/dart_change_workspace.dart';
 import 'package:analyzer/dart/analysis/session.dart';
@@ -33,19 +33,16 @@ class CiderAssistsComputer {
 
     await _logger.runAsync('Compute assists', () async {
       try {
-        var workspace = DartChangeWorkspace([resolvedUnit.session]);
-        var context = DartAssistContextImpl(
+        var context = DartAssistContext(
           InstrumentationService.NULL_SERVICE,
-          workspace,
+          DartChangeWorkspace([resolvedUnit.session]),
           resolvedLibrary,
           resolvedUnit,
           offset,
           length,
         );
-        var processor = AssistProcessor(context);
-        var assists = await processor.compute();
-        assists.sort(Assist.compareAssists);
-        result.addAll(assists);
+        var assists = await computeAssists(context);
+        result.addAll(assists..sort(Assist.compareAssists));
       } on InconsistentAnalysisException {
         // If an InconsistentAnalysisException occurs, it's likely the user modified
         // the source and therefore is no longer interested in the results.

pkg/analysis_server/lib/src/handler/legacy/edit_get_assists.dart

@@ -10,8 +10,8 @@ import 'package:analysis_server/src/handler/legacy/legacy_handler.dart';
 import 'package:analysis_server/src/legacy_analysis_server.dart';
 import 'package:analysis_server/src/plugin/result_converter.dart';
 import 'package:analysis_server/src/request_handler_mixin.dart';
-import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server_plugin/src/correction/assist_core.dart';
+import 'package:analysis_server_plugin/src/correction/assist_dart.dart';
 import 'package:analysis_server_plugin/src/correction/assist_performance.dart';
 import 'package:analysis_server_plugin/src/correction/assist_processor.dart';
 import 'package:analysis_server_plugin/src/correction/dart_change_workspace.dart';
@@ -101,7 +101,7 @@ class EditGetAssistsHandler extends LegacyHandler
 
     if (libraryResult != null) {
       var unitResult = libraryResult.unitWithPath(file)!;
-      var context = DartAssistContextImpl(
+      var context = DartAssistContext(
         server.instrumentationService,
         DartChangeWorkspace(await server.currentSessions),
         libraryResult,
@@ -112,12 +112,10 @@ class EditGetAssistsHandler extends LegacyHandler
 
       try {
         var performanceTracker = AssistPerformance();
-        var processor = AssistProcessor(
+        var assists = await computeAssists(
           context,
           performance: performanceTracker,
         );
-
-        var assists = await processor.compute();
         assists.sort(Assist.compareAssists);
         for (var assist in assists) {
           changes.add(assist.change);

pkg/analysis_server/lib/src/lsp/handlers/code_actions/dart.dart

@@ -10,14 +10,14 @@ import 'package:analysis_server/src/lsp/handlers/code_actions/abstract_code_acti
 import 'package:analysis_server/src/lsp/mapping.dart';
 import 'package:analysis_server/src/protocol_server.dart'
     hide AnalysisOptions, Position;
-import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/fix_performance.dart';
 import 'package:analysis_server/src/services/correction/refactoring_performance.dart';
 import 'package:analysis_server/src/services/refactoring/framework/refactoring_context.dart';
 import 'package:analysis_server/src/services/refactoring/framework/refactoring_processor.dart';
 import 'package:analysis_server/src/services/refactoring/legacy/refactoring.dart';
 import 'package:analysis_server_plugin/edit/fix/dart_fix_context.dart';
 import 'package:analysis_server_plugin/src/correction/assist_core.dart';
+import 'package:analysis_server_plugin/src/correction/assist_dart.dart';
 import 'package:analysis_server_plugin/src/correction/assist_performance.dart';
 import 'package:analysis_server_plugin/src/correction/assist_processor.dart';
 import 'package:analysis_server_plugin/src/correction/dart_change_workspace.dart';
@@ -124,14 +124,13 @@ class DartCodeActionsProducer extends AbstractCodeActionsProducer {
   }) async {
     // These assists are only provided as literal CodeActions.
     if (!supportsLiterals) {
-      return [];
+      return const [];
     }
 
     try {
-      var workspace = DartChangeWorkspace(await server.currentSessions);
-      var context = DartAssistContextImpl(
+      var context = DartAssistContext(
         server.instrumentationService,
-        workspace,
+        DartChangeWorkspace(await server.currentSessions),
         libraryResult,
         unitResult,
         offset,
@@ -141,12 +140,11 @@ class DartCodeActionsProducer extends AbstractCodeActionsProducer {
       late List<Assist> assists;
       if (performance != null) {
         var performanceTracker = AssistPerformance();
-        var processor = AssistProcessor(
+        assists = await computeAssists(
           context,
           performance: performanceTracker,
         );
 
-        assists = await processor.compute();
         server.recentPerformance.getAssists.add(
           GetAssistsPerformance(
             performance: performance,
@@ -158,8 +156,7 @@ class DartCodeActionsProducer extends AbstractCodeActionsProducer {
           ),
         );
       } else {
-        var processor = AssistProcessor(context);
-        assists = await processor.compute();
+        assists = await computeAssists(context);
       }
 
       return assists.map((assist) {
@@ -175,7 +172,7 @@ class DartCodeActionsProducer extends AbstractCodeActionsProducer {
       // If an InconsistentAnalysisException occurs, it's likely the user modified
       // the source and therefore is no longer interested in the results, so
       // just return an empty set.
-      return [];
+      return const [];
     }
   }
 

pkg/analysis_server/lib/src/services/correction/assist.dart

@@ -2,42 +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.
 
-import 'package:analysis_server_plugin/src/correction/assist_dart.dart';
-import 'package:analysis_server_plugin/src/correction/change_workspace.dart';
-import 'package:analyzer/dart/analysis/results.dart';
-import 'package:analyzer/instrumentation/service.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 
-/// The implementation of [DartAssistContext].
-class DartAssistContextImpl implements DartAssistContext {
-  @override
-  final InstrumentationService instrumentationService;
-
-  @override
-  final ChangeWorkspace workspace;
-
-  @override
-  final ResolvedLibraryResult libraryResult;
-
-  @override
-  final ResolvedUnitResult unitResult;
-
-  @override
-  final int selectionOffset;
-
-  @override
-  final int selectionLength;
-
-  DartAssistContextImpl(
-    this.instrumentationService,
-    this.workspace,
-    this.libraryResult,
-    this.unitResult,
-    this.selectionOffset,
-    this.selectionLength,
-  );
-}
-
 /// An enumeration of possible assist kinds.
 abstract final class DartAssistKind {
   static const ADD_DIAGNOSTIC_PROPERTY_REFERENCE = AssistKind(

pkg/analysis_server/test/src/services/correction/assist/assist_processor.dart

@@ -2,8 +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.
 
-import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server_plugin/src/correction/assist_core.dart';
+import 'package:analysis_server_plugin/src/correction/assist_dart.dart';
 import 'package:analysis_server_plugin/src/correction/assist_processor.dart';
 import 'package:analysis_server_plugin/src/correction/change_workspace.dart';
 import 'package:analysis_server_plugin/src/correction/dart_change_workspace.dart';
@@ -202,16 +202,15 @@ abstract class AssistProcessorTest extends AbstractSingleUnitTest {
     if (libraryResult == null) {
       return const [];
     }
-    var context = DartAssistContextImpl(
+    var context = DartAssistContext(
       TestInstrumentationService(),
       await workspace,
       libraryResult,
       testAnalysisResult,
       _offset,
       _length,
     );
-    var processor = AssistProcessor(context);
-    return await processor.compute();
+    return await computeAssists(context);
   }
 
   List<Position> _findResultPositions(List<String> searchStrings) {

pkg/analysis_server_plugin/lib/registry.dart

@@ -7,13 +7,16 @@ import 'package:analyzer/error/error.dart';
 import 'package:analyzer/src/lint/linter.dart';
 
 abstract class PluginRegistry {
-  /// Register this fix [generator] for the given lint [code] with the
+  /// Registers this assist [generator] with the analyzer's rule registry.
+  void registerAssist(ProducerGenerator generator);
+
+  /// Registers this fix [generator] for the given lint [code] with the
   /// analyzer's rule registry.
   void registerFixForRule(LintCode code, ProducerGenerator generator);
 
-  /// Register this [rule] with the analyzer's rule registry.
+  /// Registers this [rule] with the analyzer's rule registry.
   void registerLintRule(AnalysisRule rule);
 
-  /// Register this [rule] with the analyzer's rule registry.
+  /// Registers this [rule] with the analyzer's rule registry.
   void registerWarningRule(AnalysisRule rule);
 }

pkg/analysis_server_plugin/lib/src/correction/assist_dart.dart

@@ -7,25 +7,32 @@ import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/instrumentation/service.dart';
 
 /// An object used to provide context information for Dart assist contributors.
-///
-/// Clients may not extend, implement or mix-in this class.
-abstract class DartAssistContext {
+final class DartAssistContext {
   /// The instrumentation service used to report errors that prevent a fix from
   /// being composed.
-  InstrumentationService get instrumentationService;
+  final InstrumentationService instrumentationService;
+
+  /// The workspace in which an assist operates.
+  final ChangeWorkspace workspace;
 
   /// The resolved library result in which an assist operates.
-  ResolvedLibraryResult get libraryResult;
+  final ResolvedLibraryResult libraryResult;
 
-  /// The length of the selection.
-  int get selectionLength;
+  /// The unit result in which an assist operates.
+  final ResolvedUnitResult unitResult;
 
   /// The starting offset of the selection.
-  int get selectionOffset;
+  final int selectionOffset;
 
-  /// The unit result in which an assist operates.
-  ResolvedUnitResult get unitResult;
+  /// The length of the selection.
+  final int selectionLength;
 
-  /// The workspace in which an assist operates.
-  ChangeWorkspace get workspace;
+  DartAssistContext(
+    this.instrumentationService,
+    this.workspace,
+    this.libraryResult,
+    this.unitResult,
+    this.selectionOffset,
+    this.selectionLength,
+  );
 }

pkg/analysis_server_plugin/lib/src/correction/assist_processor.dart

@@ -14,6 +14,13 @@ import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 import 'package:analyzer_plugin/utilities/change_builder/conflicting_edit_exception.dart';
 
+Future<List<Assist>> computeAssists(DartAssistContext context,
+        {AssistPerformance? performance}) =>
+    AssistProcessor(
+      context,
+      performance: performance,
+    ).compute();
+
 /// The computer for Dart assists.
 class AssistProcessor {
   final AssistPerformance? _performance;

pkg/analysis_server_plugin/lib/src/plugin_server.dart

@@ -7,6 +7,9 @@ import 'dart:async';
 import 'package:analysis_server_plugin/edit/fix/dart_fix_context.dart';
 import 'package:analysis_server_plugin/edit/fix/fix.dart';
 import 'package:analysis_server_plugin/plugin.dart';
+import 'package:analysis_server_plugin/src/correction/assist_core.dart';
+import 'package:analysis_server_plugin/src/correction/assist_dart.dart';
+import 'package:analysis_server_plugin/src/correction/assist_processor.dart';
 import 'package:analysis_server_plugin/src/correction/dart_change_workspace.dart';
 import 'package:analysis_server_plugin/src/correction/fix_processor.dart';
 import 'package:analysis_server_plugin/src/registry.dart';
@@ -98,6 +101,60 @@ class PluginServer {
     return protocol.AnalysisSetPriorityFilesResult();
   }
 
+  /// Handles an 'edit.getAssists' request.
+  ///
+  /// Throws a [RequestFailure] if the request could not be handled.
+  Future<protocol.EditGetAssistsResult> handleEditGetAssists(
+      protocol.EditGetAssistsParams parameters) async {
+    var path = parameters.file;
+
+    var recentState = _recentState[path];
+    if (recentState == null) {
+      return protocol.EditGetAssistsResult(const []);
+    }
+
+    var (:analysisContext, :errors) = recentState;
+    var libraryResult =
+        await analysisContext.currentSession.getResolvedLibrary(path);
+    if (libraryResult is! ResolvedLibraryResult) {
+      return protocol.EditGetAssistsResult(const []);
+    }
+    var unitResult = libraryResult.unitWithPath(path);
+    if (unitResult is! ResolvedUnitResult) {
+      return protocol.EditGetAssistsResult(const []);
+    }
+
+    var context = DartAssistContext(
+      // TODO(srawlins): Use a real instrumentation service. Other
+      // implementations get InstrumentationService from AnalysisServer.
+      InstrumentationService.NULL_SERVICE,
+      DartChangeWorkspace([analysisContext.currentSession]),
+      libraryResult,
+      unitResult,
+      parameters.offset,
+      parameters.length,
+    );
+
+    List<Assist> assists;
+    try {
+      assists = await computeAssists(context);
+    } on InconsistentAnalysisException {
+      // TODO(srawlins): Is it important to at least log this? Or does it
+      // happen on the regular?
+      assists = [];
+    }
+
+    if (assists.isEmpty) {
+      return protocol.EditGetAssistsResult(const []);
+    }
+
+    var corrections = [
+      for (var assist in assists..sort(Assist.compareAssists))
+        protocol.PrioritizedSourceChange(assist.kind.priority, assist.change)
+    ];
+    return protocol.EditGetAssistsResult(corrections);
+  }
+
   /// Handles an 'edit.getFixes' request.
   ///
   /// Throws a [RequestFailure] if the request could not be handled.

pkg/analysis_server_plugin/lib/src/registry.dart

@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analysis_server_plugin/registry.dart';
+import 'package:analysis_server_plugin/src/correction/assist_generators.dart';
 import 'package:analysis_server_plugin/src/correction/fix_generators.dart';
 import 'package:analysis_server_plugin/src/correction/ignore_diagnostic.dart';
 import 'package:analyzer/error/error.dart';
@@ -13,6 +14,11 @@ final class PluginRegistryImpl implements PluginRegistry {
   /// Returns currently registered lint rules.
   Iterable<AnalysisRule> get registeredRules => Registry.ruleRegistry;
 
+  @override
+  void registerAssist(ProducerGenerator generator) {
+    registeredAssistGenerators.registerGenerator(generator);
+  }
+
   @override
   void registerFixForRule(LintCode code, ProducerGenerator generator) {
     registeredFixGenerators.registerFixForLint(code, generator);