Version 2.12.0-1.0.dev

Merge commit '9ca05a40927142d3512b72055b72fccd7a1cc592' into 'dev'

Author: Dart CI

pkg/analysis_server/lib/src/computer/import_elements_computer.dart

@@ -325,15 +325,15 @@ class ImportElementsComputer {
     var scope = libraryResult.libraryElement.scope;
 
     if (prefix.isNotEmpty) {
-      var prefixElement = scope.lookup2(prefix).getter;
+      var prefixElement = scope.lookup(prefix).getter;
       if (prefixElement is PrefixElement) {
         scope = prefixElement.scope;
       } else {
         return false;
       }
     }
 
-    var lookupResult = scope.lookup2(name);
+    var lookupResult = scope.lookup(name);
     return lookupResult.getter != null || lookupResult.setter != null;
   }
 

pkg/dartdev/lib/dartdev.dart

@@ -2,7 +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 'dart:io' as io;
+// Do not call exit() directly. Use VmInteropHandler.exit() instead.
+import 'dart:io' as io hide exit;
 import 'dart:isolate';
 
 import 'package:analyzer/src/dart/analysis/experiments.dart';
@@ -29,8 +30,7 @@ import 'src/utils.dart';
 import 'src/vm_interop_handler.dart';
 
 /// This is typically called from bin/, but given the length of the method and
-/// analytics logic, it has been moved here. Also note that this method calls
-/// [io.exit(code)] directly.
+/// analytics logic, it has been moved here.
 Future<void> runDartdev(List<String> args, SendPort port) async {
   VmInteropHandler.initialize(port);
 
@@ -69,13 +69,15 @@ Future<void> runDartdev(List<String> args, SendPort port) async {
 
     // Alert the user that analytics has been disabled.
     print(analyticsDisabledNoticeMessage);
-    io.exit(0);
+    VmInteropHandler.exit(0);
+    return;
   } else if (args.contains('--enable-analytics')) {
     analytics.enabled = true;
 
     // Alert the user again that anonymous data will be collected.
     print(analyticsNoticeOnFirstRunMessage);
-    io.exit(0);
+    VmInteropHandler.exit(0);
+    return;
   }
 
   try {

pkg/nnbd_migration/lib/migration_cli.dart

@@ -314,11 +314,8 @@ class MigrationCli {
         CommandLineOptions.skipPubOutdatedFlag,
         (parser, hide) => parser.addFlag(
               CommandLineOptions.skipPubOutdatedFlag,
-              // TODO(srawlins): Before "beta," change the default to "false," and
-              // negatable to "false." See
-              // https://github.com/dart-lang/sdk/issues/43774.
-              defaultsTo: true,
-              negatable: true,
+              defaultsTo: false,
+              negatable: false,
               help:
                   'Skip the `pub outdated --mode=null-safety` check. This allows a '
                   'migration to proceed even if some package dependencies have not yet '

pkg/nnbd_migration/lib/nnbd_migration.dart

@@ -117,6 +117,12 @@ class NullabilityFixDescription {
     kind: NullabilityFixKind.downcastExpression,
   );
 
+  /// Informative message: there is no valid migration for `null` in a
+  /// non-nullable context.
+  static const noValidMigrationForNull = NullabilityFixDescription._(
+      appliedMessage: 'No valid migration for `null` in a non-nullable context',
+      kind: NullabilityFixKind.noValidMigrationForNull);
+
   /// Informative message: a null-aware access won't be necessary in strong
   /// checking mode.
   static const nullAwarenessUnnecessaryInStrongMode =
@@ -276,6 +282,7 @@ enum NullabilityFixKind {
   downcastExpression,
   makeTypeNullable,
   makeTypeNullableDueToHint,
+  noValidMigrationForNull,
   nullAwarenessUnnecessaryInStrongMode,
   nullAwareAssignmentUnnecessaryInStrongMode,
   otherCastExpression,

pkg/nnbd_migration/lib/src/fix_aggregator.dart

@@ -684,6 +684,10 @@ class NodeChangeForDefaultFormalParameter
 /// Implementation of [NodeChange] specialized for operating on [Expression]
 /// nodes.
 class NodeChangeForExpression<N extends Expression> extends NodeChange<N> {
+  bool _addsNoValidMigration = false;
+
+  AtomicEditInfo _addNoValidMigrationInfo;
+
   bool _addsNullCheck = false;
 
   AtomicEditInfo _addNullCheckInfo;
@@ -696,9 +700,15 @@ class NodeChangeForExpression<N extends Expression> extends NodeChange<N> {
 
   NodeChangeForExpression() : super._();
 
+  /// Gets the info for any added "no valid migration" comment.
+  AtomicEditInfo get addNoValidMigrationInfo => _addNoValidMigrationInfo;
+
   /// Gets the info for any added null check.
   AtomicEditInfo get addNullCheckInfo => _addNullCheckInfo;
 
+  /// Indicates whether [addNoValidMigration] has been called.
+  bool get addsNoValidMigration => _addsNoValidMigration;
+
   /// Indicates whether [addNullCheck] has been called.
   bool get addsNullCheck => _addsNullCheck;
 
@@ -711,10 +721,17 @@ class NodeChangeForExpression<N extends Expression> extends NodeChange<N> {
 
   @override
   Iterable<String> get _toStringParts => [
+        if (_addsNoValidMigration) 'addsNoValidMigration',
         if (_addsNullCheck) 'addsNullCheck',
         if (_introducesAsType != null) 'introducesAsType'
       ];
 
+  void addNoValidMigration(AtomicEditInfo info) {
+    assert(!_addsNoValidMigration);
+    _addsNoValidMigration = true;
+    _addNoValidMigrationInfo = info;
+  }
+
   /// Causes a null check to be added to this expression, with the given [info].
   void addNullCheck(AtomicEditInfo info, {HintComment hint}) {
     assert(!_addsNullCheck);
@@ -754,6 +771,11 @@ class NodeChangeForExpression<N extends Expression> extends NodeChange<N> {
             .addUnaryPostfix(plan, TokenType.BANG, info: _addNullCheckInfo);
       }
     }
+    if (_addsNoValidMigration) {
+      plan = aggregator.planner.addCommentPostfix(
+          plan, '/* no valid migration */',
+          info: _addNoValidMigrationInfo, isInformative: true);
+    }
     if (_introducesAsType != null) {
       plan = aggregator.planner.addBinaryPostfix(
           plan, TokenType.AS, aggregator.typeToCode(_introducesAsType),

pkg/nnbd_migration/lib/src/fix_builder.dart

@@ -573,12 +573,21 @@ class MigrationResolutionHooksImpl
       {AtomicEditInfo info, HintComment hint}) {
     var checks =
         _fixBuilder._variables.expressionChecks(_fixBuilder.source, node);
+    bool noValidMigration = node is NullLiteral && hint == null;
     info ??= checks != null
         ? AtomicEditInfo(
-            NullabilityFixDescription.checkExpression, checks.edges)
+            noValidMigration
+                ? NullabilityFixDescription.noValidMigrationForNull
+                : NullabilityFixDescription.checkExpression,
+            checks.edges)
         : null;
-    (_fixBuilder._getChange(node) as NodeChangeForExpression)
-        .addNullCheck(info, hint: hint);
+    var nodeChangeForExpression =
+        _fixBuilder._getChange(node) as NodeChangeForExpression;
+    if (noValidMigration) {
+      nodeChangeForExpression.addNoValidMigration(info);
+    } else {
+      nodeChangeForExpression.addNullCheck(info, hint: hint);
+    }
     _flowAnalysis.nonNullAssert_end(node);
     return _fixBuilder._typeSystem.promoteToNonNull(type as TypeImpl);
   }

pkg/nnbd_migration/lib/src/front_end/info_builder.dart

@@ -211,6 +211,10 @@ class InfoBuilder {
         // their "OrNull" equivalents.  We don't offer any hints around
         // this transformation.
         break;
+      case NullabilityFixKind.noValidMigrationForNull:
+        // We don't offer any edits around unmigratable `null`s.  The user has
+        // to fix manually.
+        break;
     }
     return edits;
   }

pkg/nnbd_migration/lib/src/front_end/migration_summary.dart

@@ -94,6 +94,8 @@ class MigrationSummary {
         return 'makeTypeNullable';
       case NullabilityFixKind.makeTypeNullableDueToHint:
         return 'makeTypeNullableDueToHint';
+      case NullabilityFixKind.noValidMigrationForNull:
+        return 'noValidMigrationForNull';
       case NullabilityFixKind.nullAwarenessUnnecessaryInStrongMode:
         return 'nullAwarenessUnnecessaryInStrongMode';
       case NullabilityFixKind.nullAwareAssignmentUnnecessaryInStrongMode:

pkg/nnbd_migration/lib/src/front_end/non_nullable_fix.dart

@@ -4,7 +4,6 @@
 
 import 'dart:convert' show jsonDecode, JsonEncoder;
 
-import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/file_system/file_system.dart';
@@ -30,11 +29,11 @@ class NonNullableFix {
   // TODO(srawlins): Refactor to use
   //  `Feature.non_nullable.releaseVersion` when this becomes non-null (perhaps
   //  after "Beta").
-  static final Version _intendedMinimumSdkVersion =
-      Feature.non_nullable.experimentalReleaseVersion;
+  static final Version _intendedMinimumSdkVersion = Version.parse('2.12.0-0');
 
   // In the package_config.json file, the patch number is omitted.
-  static const String _intendedLanguageVersion = '2.10';
+  static final String _intendedLanguageVersion =
+      '${_intendedMinimumSdkVersion.major}.${_intendedMinimumSdkVersion.minor}';
 
   static final String _intendedSdkVersionConstraint =
       '>=$_intendedMinimumSdkVersion <2.12.0';
@@ -153,9 +152,6 @@ class NonNullableFix {
     if (updated) {
       _processConfigFile(pkgFolder, pubspec);
     }
-    // TODO(https://github.com/dart-lang/sdk/issues/43806): stop processing
-    // analysis options file when the experiment is no longer needed.
-    _processAnalysisOptionsFile(pkgFolder);
   }
 
   Future<void> processUnit(ResolvedUnitResult result) async {
@@ -212,91 +208,6 @@ class NonNullableFix {
     }
   }
 
-  void _processAnalysisOptionsException(
-      String action, String analysisOptionsPath, error) {
-    listener.addRecommendation('''Failed to $action analysis options file
-  $analysisOptionsPath
-  $error
-
-  Manually update this file to enable the Null Safety language feature in static
-  analysis by adding:
-
-    analyzer:
-      enable-experiment:
-        - non-nullable
-''');
-  }
-
-  void _processAnalysisOptionsFile(Folder pkgFolder) {
-    var analysisOptionsFile =
-        pkgFolder.getChildAssumingFile('analysis_options.yaml');
-    if (!analysisOptionsFile.exists) {
-      // A source file edit cannot be made for a file which doesn't exist.
-      // Instead of using the fix listener, just write the file directly.
-      analysisOptionsFile.writeAsStringSync('''
-analyzer:
-  enable-experiment:
-    - non-nullable
-
-''');
-      return;
-    }
-
-    _YamlFile analysisOptions;
-    try {
-      analysisOptions = _YamlFile._parseFrom(analysisOptionsFile);
-    } on FileSystemException catch (e) {
-      _processAnalysisOptionsException('read', analysisOptionsFile.path, e);
-      return;
-    } on FormatException catch (e) {
-      _processAnalysisOptionsException('parse', analysisOptionsFile.path, e);
-      return;
-    }
-
-    var analysisOptionsMap = analysisOptions.content;
-    YamlNode analyzerOptions;
-    if (analysisOptionsMap is YamlMap) {
-      analyzerOptions = analysisOptionsMap.nodes['analyzer'];
-    }
-    if (analyzerOptions == null) {
-      // There is no top-level "analyzer" section. We can write one in its
-      // entirety, and use a 2-space indentation. This is a valid indentation,
-      // even if the file contains another top-level section (perhaps "linter")
-      // which uses a different indentation.
-      var start = SourceLocation(0, line: 0, column: 0);
-      var content = '''
-analyzer:
-  enable-experiment:
-    - non-nullable
-
-''';
-      analysisOptions._insertAfterParent(
-          SourceSpan(start, start, ''), content, listener);
-    } else if (analyzerOptions is YamlMap) {
-      var enableExperiment = analyzerOptions.nodes['enable-experiment'];
-      if (enableExperiment == null) {
-        var analyzerIndentation =
-            analysisOptions._getMapEntryIndentation(analyzerOptions);
-        var indent = ' ' * analyzerIndentation;
-        var content = '\n'
-            '${indent}enable-experiment:\n'
-            '$indent  - non-nullable';
-        analysisOptions._insertAfterParent(
-            analyzerOptions.span, content, listener);
-      } else if (enableExperiment is YamlList) {
-        var enableExperimentIndentation =
-            analysisOptions._getListIndentation(enableExperiment);
-        var indent = ' ' * enableExperimentIndentation;
-        var nonNullableIsEnabled = enableExperiment.value
-            .any((experiment) => experiment == 'non-nullable');
-        if (nonNullableIsEnabled) return;
-        var content = '\n' '$indent- non-nullable';
-        analysisOptions._insertAfterParent(
-            enableExperiment.span, content, listener);
-      }
-    }
-  }
-
   /// Updates the Package Config file to specify a minimum Dart SDK version
   /// which supports null safety.
   void _processConfigFile(Folder pkgFolder, _YamlFile pubspec) {
@@ -516,48 +427,13 @@ $stackTrace''');
 }
 
 class _YamlFile {
-  static final _newlineCharacter = RegExp('[\r\n]');
   final String path;
   final String textContent;
 
   final YamlNode content;
 
   _YamlFile._(this.path, this.textContent, this.content);
 
-  /// Returns the indentation of the entries in [node].
-  int _getListIndentation(YamlList node) {
-    return node.span.start.column;
-  }
-
-  /// Returns the indentation of the first (and presumably all) entry of [node].
-  int _getMapEntryIndentation(YamlMap node) {
-    if (node.isEmpty) return 2;
-
-    var value = node.nodes.values.first;
-    if (value is YamlScalar) {
-      // A YamlScalar value indicates that a "key: value" pair is on a single
-      // line. The span's start column is the start column of the value, not the
-      // key.
-      var offset = value.span.start.offset;
-      var firstSpaceIndex =
-          textContent.lastIndexOf(_newlineCharacter, offset) + 1;
-      var index = firstSpaceIndex;
-      while (textContent.codeUnitAt(index) == $space) {
-        index++;
-      }
-      return index - firstSpaceIndex;
-    } else if (value is YamlMap) {
-      // If the first entry of [node] is a YamlMap, then the span for [node]
-      // indicates the start of the first entry.
-      return node.span.start.column;
-    } else {
-      assert(value is YamlList);
-      // If the first entry of [node] is a YamlList, then the span for [value]
-      // indicates the start of the first list entry.
-      return value.span.start.column;
-    }
-  }
-
   String _getName() {
     YamlNode packageNameNode;
 

pkg/nnbd_migration/lib/src/front_end/unit_renderer.dart

@@ -23,6 +23,7 @@ class UnitRenderer {
   /// "proposed edits" area, in the order in which they should be displayed.
   @visibleForTesting
   static const List<NullabilityFixKind> kindPriorityOrder = [
+    NullabilityFixKind.noValidMigrationForNull,
     NullabilityFixKind.compoundAssignmentHasBadCombinedType,
     NullabilityFixKind.compoundAssignmentHasNullableSource,
     NullabilityFixKind.removeDeadCode,
@@ -316,6 +317,8 @@ class UnitRenderer {
         return '$count type$s made nullable';
       case NullabilityFixKind.makeTypeNullableDueToHint:
         return '$count nullability hint$s converted to ?$s';
+      case NullabilityFixKind.noValidMigrationForNull:
+        return '$count literal `null`$s could not be migrated';
       case NullabilityFixKind.nullAwarenessUnnecessaryInStrongMode:
         return '$count null-aware access$es will be unnecessary in strong '
             'checking mode';