Verify that 'utf8.encode()' is not used in the analyzer.

To be removed after Dart SDK 3.1 is published, and the analyzer
SDK constraints updated.

See
https://dart-review.googlesource.com/c/sdk/+/254903

Change-Id: I2c3321d991cd3e123f08c5a360487362be16f258
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/313920
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Samuel Rawlins <srawlins@google.com>

pkg/_fe_analyzer_shared/lib/src/scanner/scanner.dart

@@ -6,7 +6,7 @@ library _fe_analyzer_shared.scanner;
 
 import 'dart:typed_data' show Uint8List;
 
-import 'dart:convert' show unicodeReplacementCharacterRune, utf8;
+import 'dart:convert' show Utf8Encoder, unicodeReplacementCharacterRune;
 
 import 'token.dart' show Token;
 
@@ -98,7 +98,7 @@ ScannerResult _tokenizeAndRecover(Scanner scanner,
     {List<int>? bytes, String? source}) {
   Token tokens = scanner.tokenize();
   if (scanner.hasErrors) {
-    if (bytes == null) bytes = utf8.encode(source!);
+    if (bytes == null) bytes = const Utf8Encoder().convert(source!);
     tokens = scannerRecovery(bytes, tokens, scanner.lineStarts);
   }
   return new ScannerResult(tokens, scanner.lineStarts, scanner.hasErrors);

pkg/analysis_server/test/test_all.dart

@@ -30,6 +30,7 @@ import 'tool/test_all.dart' as tool;
 import 'utilities/test_all.dart' as utilities;
 import 'verify_error_fix_status_test.dart' as verify_error_fix_status;
 import 'verify_no_solo_test.dart' as verify_no_solo;
+import 'verify_no_utf8_encode_test.dart' as verify_no_utf8_encode;
 import 'verify_sorted_test.dart' as verify_sorted;
 import 'verify_tests_test.dart' as verify_tests;
 
@@ -60,6 +61,7 @@ void main() {
     utilities.main();
     verify_error_fix_status.main();
     verify_no_solo.main();
+    verify_no_utf8_encode.main();
     verify_sorted.main();
     verify_tests.main();
     defineReflectiveSuite(() {

pkg/analysis_server/test/verify_no_utf8_encode_test.dart

@@ -0,0 +1,62 @@
+// Copyright (c) 2023, 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:collection';
+
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/file_system/physical_file_system.dart';
+import 'package:analyzer/src/util/file_paths.dart' as file_paths;
+import 'package:analyzer_utilities/package_root.dart';
+import 'package:test/test.dart';
+
+/// TODO(scheglov) Remove it after SDK 3.1 published.
+void main() {
+  group('_fe_analyzer_shared', () {
+    buildTests(packagePath: '_fe_analyzer_shared');
+  });
+
+  group('analyzer', () {
+    buildTests(packagePath: 'analyzer');
+  });
+}
+
+void buildTests({required String packagePath}) {
+  final provider = PhysicalResourceProvider.INSTANCE;
+  final pathContext = provider.pathContext;
+  final pkgRootPath = pathContext.normalize(packageRoot);
+
+  final libFolder = provider
+      .getFolder(pkgRootPath)
+      .getChildAssumingFolder(packagePath)
+      .getChildAssumingFolder('lib');
+
+  for (final file in libFolder.allFiles) {
+    if (file_paths.isDart(pathContext, file.path)) {
+      test(file.path, () {
+        final content = file.readAsStringSync();
+        if (content.contains('utf8.encode')) {
+          fail('Should not use `utf8.encode` before SDK 3.1');
+        }
+      });
+    }
+  }
+}
+
+extension on Folder {
+  Iterable<File> get allFiles sync* {
+    final queue = Queue<Folder>();
+    queue.add(this);
+    while (queue.isNotEmpty) {
+      final current = queue.removeFirst();
+      final children = current.getChildren();
+      for (final child in children) {
+        if (child is File) {
+          yield child;
+        } else if (child is Folder) {
+          queue.add(child);
+        }
+      }
+    }
+  }
+}

pkg/analyzer/lib/src/summary/api_signature.dart

@@ -96,7 +96,7 @@ class ApiSignature {
 
   /// Collect a string.
   void addString(String s) {
-    List<int> bytes = utf8.encode(s);
+    final bytes = const Utf8Encoder().convert(s);
     addInt(bytes.length);
     addBytes(bytes);
   }

pkg/analyzer/lib/src/summary/flat_buffers.dart

@@ -403,7 +403,7 @@ class Builder {
     _ensureNoVTable();
     return _strings.putIfAbsent(value, () {
       // TODO(scheglov) optimize for ASCII strings
-      List<int> bytes = utf8.encode(value);
+      final bytes = const Utf8Encoder().convert(value);
       int length = bytes.length;
       _prepare(4, 1, additionalBytes: length);
       Offset<String> result = Offset(_tail);

pkg/analyzer/lib/src/summary2/data_writer.dart

@@ -178,7 +178,8 @@ class BufferedSink {
 
   /// Write the [value] as UTF8 encoded byte array.
   void writeStringUtf8(String value) {
-    writeUint8List(const Utf8Encoder().convert(value));
+    final bytes = const Utf8Encoder().convert(value);
+    writeUint8List(bytes);
   }
 
   void writeStringUtf8Iterable(Iterable<String> items) {

pkg/analyzer/lib/src/summary2/kernel_compilation_service.dart

@@ -104,7 +104,7 @@ class KernelCompilationService {
       });
       requestChannel.add('file.readAsBytes', (uriStr) async {
         final content = uriStrToFile(uriStr).content;
-        return utf8.encode(content);
+        return const Utf8Encoder().convert(content);
       });
       requestChannel.add('file.readAsStringSync', (uriStr) async {
         return uriStrToFile(uriStr).content;