[analyzer] Add benchmark that calls getFixes on an actual error

This CL adds a benchmark for getFixes calls on an actual error case.
The time it takes is nowhere near the times we're seeing in
http://b/407797012 but it's better than nothing.

The benchmark does 5 requests for `getFixes`.
The first one is always much slower because it has to "discover files".

Comparing old dart releases and CLs
https://dart-review.googlesource.com/c/sdk/+/420323 and
https://dart-review.googlesource.com/c/sdk/+/421220:

3.7.2 was quite a bit slower than 3.6.2.
Both CL 420323 and CL 421220 improve things - both separately and combined.
With both we're faster than 3.6.2 for all but the first getFixes call
(which has to "discover files").

Details:

```
Comparing 3.5.4 with 3.6.2
no change.

Comparing 3.6.2 with 3.7.2
Fixes (1): 16.4789% +/- 8.3240% (0.23 +/- 0.12) (1.39 -> 1.62)
Fixes (2): 300.2940% +/- 21.5781% (0.06 +/- 0.00) (0.02 -> 0.08)
Fixes (3): 220.0321% +/- 23.8171% (0.05 +/- 0.01) (0.02 -> 0.07)
Fixes (4): 89.0472% +/- 86.0948% (0.03 +/- 0.03) (0.04 -> 0.07)
Fixes (5): 202.9467% +/- 22.5906% (0.04 +/- 0.00) (0.02 -> 0.07)

Comparing 3.7.2 with HEAD-ish without the two CLs
Fixes (1): 9.2103% +/- 6.7559% (0.15 +/- 0.11) (1.62 -> 1.77)
Fixes (2): -32.2017% +/- 7.2433% (-0.03 +/- 0.01) (0.08 -> 0.06)
Fixes (3): -39.1903% +/- 7.4656% (-0.03 +/- 0.01) (0.07 -> 0.04)
Fixes (4): -41.5019% +/- 8.2911% (-0.03 +/- 0.01) (0.07 -> 0.04)
Fixes (5): -38.7623% +/- 4.4327% (-0.03 +/- 0.00) (0.07 -> 0.04)

Comparing HEAD-ish without the two CLs with CL 420323 (cache) only
Fixes (1): -5.9976% +/- 4.4944% (-0.11 +/- 0.08) (1.77 -> 1.66)
Fixes (4): -39.3839% +/- 13.3201% (-0.02 +/- 0.01) (0.04 -> 0.02)
Fixes (5): -49.0495% +/- 4.2557% (-0.02 +/- 0.00) (0.04 -> 0.02)

Comparing CL 420323 (cache) only with CL 421220 (element2) only
Fixes (2): -63.4332% +/- 42.9828% (-0.02 +/- 0.02) (0.04 -> 0.01)
Fixes (3): -79.6318% +/- 17.5009% (-0.04 +/- 0.01) (0.05 -> 0.01)
Fixes (4): -68.4995% +/- 11.7414% (-0.02 +/- 0.00) (0.02 -> 0.01)
Fixes (5): -54.6697% +/- 11.1116% (-0.01 +/- 0.00) (0.02 -> 0.01)

Comparing CL 421220 (element2) only with both
Fixes (2): -21.3437% +/- 7.8302% (-0.00 +/- 0.00) (0.01 -> 0.01)
Fixes (3): -17.7975% +/- 10.4789% (-0.00 +/- 0.00) (0.01 -> 0.01)
Fixes (5): -30.5353% +/- 20.5827% (-0.00 +/- 0.00) (0.01 -> 0.01)
```

Change-Id: I477c7a73c669099e2d7bc9d64000cfb78ced2ea4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/421601
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Jens Johansen <[email protected]>

Author: jensjoha

pkg/analysis_server/tool/benchmark_tools/big_chain_benchmark/benchmark_utils.dart

@@ -121,6 +121,17 @@ $typing
 """;
   var typingAtOffset = mainFileTypingContent.indexOf(typing) + typing.length;
 
+  var typingError = 'getFooBarBaz';
+  var mainFileTypingErrorContent = """
+import '${getFilenameFor(1)}';
+
+void main(List<String> arguments) {
+  arguments.$typingError();
+}
+""";
+  var typingErrorAtOffset =
+      mainFileTypingErrorContent.indexOf(typingError) + typingError.length;
+
   if (includePlugin) {
     String executableToUse = extractDartParamOrDefault(args);
     void pubGetIn(String dir) {
@@ -196,6 +207,8 @@ analyzer:
     mainFile: FileContentPair(mainFileUri, mainFileContent),
     mainFileTypingContent: mainFileTypingContent,
     typingAtOffset: typingAtOffset,
+    mainFileTypingErrorContent: mainFileTypingErrorContent,
+    typingErrorAtOffset: typingErrorAtOffset,
     orderedFileCopies: orderedFileCopies,
     numFiles: numFiles,
   );
@@ -243,6 +256,8 @@ class RunDetails {
   final FileContentPair mainFile;
   final String mainFileTypingContent;
   final int typingAtOffset;
+  final String mainFileTypingErrorContent;
+  final int typingErrorAtOffset;
   final List<FileContentPair> orderedFileCopies;
   final int numFiles;
 
@@ -251,6 +266,8 @@ class RunDetails {
     required this.mainFile,
     required this.mainFileTypingContent,
     required this.typingAtOffset,
+    required this.mainFileTypingErrorContent,
+    required this.typingErrorAtOffset,
     required this.orderedFileCopies,
     required this.numFiles,
   });

pkg/analysis_server/tool/benchmark_tools/big_chain_benchmark/legacy_get_fixes_on_error.dart

@@ -0,0 +1,84 @@
+// Copyright (c) 2025, 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 '../language_server_benchmark.dart';
+import '../legacy_messages.dart';
+import '../run_utils.dart';
+import 'benchmark_utils.dart';
+
+/// Call getFixes on an actual error, just like IntelliJ would when the cursor
+/// is on an error.
+Future<void> main(List<String> args) async {
+  await runHelper(
+    args,
+    LegacyGetFixesOnErrorBenchmark.new,
+    copyData,
+    extraIterations: getExtraIterations,
+    runAsLsp: false,
+  );
+}
+
+class LegacyGetFixesOnErrorBenchmark extends DartLanguageServerBenchmark {
+  @override
+  final Uri rootUri;
+  @override
+  final Uri cacheFolder;
+
+  final RunDetails runDetails;
+
+  LegacyGetFixesOnErrorBenchmark(
+    super.args,
+    this.rootUri,
+    this.cacheFolder,
+    this.runDetails,
+  ) : super(useLspProtocol: false);
+
+  @override
+  LaunchFrom get launchFrom => LaunchFrom.Dart;
+
+  @override
+  Future<void> afterInitialization() async {
+    // The main file is an open tab.
+    await send(
+      LegacyMessages.setPriorityFiles(largestIdSeen + 1, [
+        runDetails.mainFile.uri,
+      ]),
+    );
+
+    // Does this change anything?
+    await Future.delayed(const Duration(milliseconds: 100));
+
+    var isNowAnalyzingFuture = waitUntilIsAnalyzingChanges();
+
+    // The user typed, but it's an error.
+    await send(
+      LegacyMessages.updateContent(
+        largestIdSeen + 1,
+        runDetails.mainFile.uri,
+        runDetails.mainFileTypingErrorContent,
+      ),
+    );
+
+    bool isAnalyzing = await isNowAnalyzingFuture;
+    if (isAnalyzing == false) throw 'Expected true.';
+    await waitWhileAnalyzing();
+
+    // It's done analyzing: Ask for fixes on the error.
+    for (int i = 0; i < 5; i++) {
+      Stopwatch stopwatch = Stopwatch()..start();
+      var result =
+          await (await send(
+            LegacyMessages.getFixes(
+              largestIdSeen + 1,
+              runDetails.mainFile.uri,
+              runDetails.typingErrorAtOffset,
+            ),
+          ))!.completer.future;
+      stopwatch.stop();
+      var error = result['result']['fixes'].first['error']['type'];
+      if (error != 'COMPILE_TIME_ERROR') throw 'Expected COMPILE_TIME_ERROR';
+      durationInfo.add(DurationInfo('Fixes (${i + 1})', stopwatch.elapsed));
+    }
+  }
+}