Disable watching for files generated by Bazel

Apparently this is causing some performance issues, so we might
want to disable this until we can benchmark and optimize it.

Bug: 44484
Change-Id: I8a661b128cbc8fdd425e4d3516a7ac132e511a99
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/176521
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: David Morgan <[email protected]>

Author: michalt

pkg/analysis_server/lib/src/context_manager.dart

@@ -38,6 +38,14 @@ import 'package:path/path.dart' as pathos;
 import 'package:watcher/watcher.dart';
 import 'package:yaml/yaml.dart';
 
+/// Enables watching of files generated by Bazel.
+///
+/// TODO(michalt): This is a temporary flag that we use to disable this
+/// functionality due its performance issues. We plan to benchmark and optimize
+/// it and re-enable it everywhere.
+/// Not private to enable testing.
+var experimentalEnableBazelWatching = false;
+
 /// An indication of which files have been added, changed, removed, or deleted.
 ///
 /// No file should be added to the change set more than once, either with the
@@ -1560,6 +1568,7 @@ class ContextManagerImpl implements ContextManager {
   ///
   /// Does nothing if the [driver] is not in a Bazel workspace.
   void _watchBazelFilesIfNeeded(Folder folder, AnalysisDriver analysisDriver) {
+    if (!experimentalEnableBazelWatching) return;
     var workspace = analysisDriver.analysisContext.workspace;
     if (workspace is BazelWorkspace &&
         !bazelSubscriptions.containsKey(folder)) {

pkg/analysis_server/test/analysis/bazel_changes_test.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
+import 'package:analysis_server/src/context_manager.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
@@ -36,6 +37,8 @@ class BazelChangesTest extends AbstractAnalysisTest {
   void setUp() {
     super.setUp();
 
+    experimentalEnableBazelWatching = true;
+
     projectPath = convertPath('/workspaceRoot/third_party/dart/project');
     testFile =
         convertPath('/workspaceRoot/third_party/dart/project/lib/test.dart');
@@ -50,6 +53,8 @@ class BazelChangesTest extends AbstractAnalysisTest {
     // file watchers.
     server.contextManager.setRoots([], []);
 
+    experimentalEnableBazelWatching = false;
+
     super.tearDown();
   }