Add "Add 'late' hint" feature
Tested with:
* top-level variables
* local variables
* instance and static fields declared in classes and mixins (enhanced enums are not supported pre-null safety)
Fixes https://github.com/dart-lang/sdk/issues/41389
Change-Id: I8a89668fffe64fff508d0aeb36aaebef5c84f223
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/263460
Reviewed-by: Paul Berry <paulberry@google.com>
Commit-Queue: Samuel Rawlins <srawlins@google.com>
diff --git a/pkg/nnbd_migration/lib/src/front_end/info_builder.dart b/pkg/nnbd_migration/lib/src/front_end/info_builder.dart
index beb0e96..9e43729 100644
--- a/pkg/nnbd_migration/lib/src/front_end/info_builder.dart
+++ b/pkg/nnbd_migration/lib/src/front_end/info_builder.dart
@@ -8,6 +8,7 @@
import 'package:analyzer/dart/analysis/results.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/src/dart/ast/utilities.dart';
import 'package:analyzer_plugin/protocol/protocol_common.dart'
show SourceFileEdit;
import 'package:analyzer_plugin/protocol/protocol_common.dart' as protocol;
@@ -225,6 +226,13 @@
case NullabilityFixKind.typeNotMadeNullable:
edits.add(EditDetail('Add /*!*/ hint', offset, 0, '/*!*/'));
edits.add(EditDetail('Add /*?*/ hint', offset, 0, '/*?*/'));
+ var declarationList = _findVariableDeclaration(result.unit, offset);
+ if (declarationList != null) {
+ var lateOffset = _offsetForPossibleLateModifier(declarationList);
+ if (lateOffset != null) {
+ edits.add(EditDetail('Add late hint', lateOffset, 0, '/*late*/'));
+ }
+ }
break;
case NullabilityFixKind.makeTypeNullableDueToHint:
edits.add(changeHint('Change to /*!*/ hint', '/*!*/'));
@@ -504,6 +512,18 @@
return null;
}
+ /// Returns the variable declaration which covers [offset], or `null` if none
+ /// does.
+ VariableDeclarationList? _findVariableDeclaration(
+ CompilationUnit unit, int offset) {
+ var nodeLocator = NodeLocator2(offset);
+ var node = nodeLocator.searchWithin(unit);
+ if (node == null) {
+ return null;
+ }
+ return node.thisOrAncestorOfType<VariableDeclarationList>();
+ }
+
TraceEntryInfo _makeTraceEntry(
String description, CodeReference? codeReference,
{List<HintAction> hintActions = const []}) {
@@ -527,6 +547,34 @@
.toList());
}
+ /// Returns the offset for a possible `late` modifier which could be inserted
+ /// into [declarationList], or `null` if none is possible.
+ int? _offsetForPossibleLateModifier(VariableDeclarationList declarationList) {
+ if (declarationList.isLate || declarationList.isConst) {
+ // Don't offer an ofset.
+ return null;
+ }
+ var keyword = declarationList.keyword;
+ if (keyword != null) {
+ // Offset for possible `late` is before `var`, `const`, or `final`.
+ return keyword.offset;
+ }
+
+ var typeAnnotation = declarationList.type;
+ if (typeAnnotation != null) {
+ // Without a `keyword`, offset for possible `late` is before the type
+ // annotation.
+ return typeAnnotation.offset;
+ }
+
+ assert(
+ false,
+ 'In this VariableDeclarationList, there is no `var`, '
+ '`const`, or `final` keyword, nor any type annotation. This variable '
+ 'declaration list is not valid: $declarationList');
+ return null;
+ }
+
TraceEntryInfo _stepToTraceEntry(PropagationStepInfo step) {
var description = step.edge?.description;
description ??= step.toString(); // TODO(paulberry): improve this message.
diff --git a/pkg/nnbd_migration/test/front_end/info_builder_test.dart b/pkg/nnbd_migration/test/front_end/info_builder_test.dart
index 9bfd701..7e92ff9 100644
--- a/pkg/nnbd_migration/test/front_end/info_builder_test.dart
+++ b/pkg/nnbd_migration/test/front_end/info_builder_test.dart
@@ -384,6 +384,192 @@
replacement: ''));
}
+ Future<void> test_addLateHint_classMultipleTypedInstanceVariable() async {
+ addMetaPackage();
+ var unit = await buildInfoForSingleTestFile('''
+class C {
+ int f, g;
+ C() {
+ f = 1;
+ }
+}
+''', migratedContent: '''
+class C {
+ int? f, g;
+ C() {
+ f = 1;
+ }
+}
+''');
+ var regions = unit.fixRegions;
+ expect(regions, hasLength(1));
+ var region = regions[0];
+ var edits = region.edits;
+ assertRegion(
+ region: region,
+ offset: 15,
+ length: 1,
+ explanation: "Changed type 'int' to be nullable",
+ kind: NullabilityFixKind.makeTypeNullable);
+ assertEdit(edit: edits[2], offset: 12, length: 0, replacement: '/*late*/');
+ }
+
+ Future<void> test_addLateHint_classTypedFinalInstanceVariable() async {
+ addMetaPackage();
+ var unit = await buildInfoForSingleTestFile('''
+class C {
+ final int f;
+ C({this.f});
+}
+''', migratedContent: '''
+class C {
+ final int? f;
+ C({this.f});
+}
+''');
+ var regions = unit.fixRegions;
+ expect(regions, hasLength(1));
+ var region = regions[0];
+ var edits = region.edits;
+ assertRegion(
+ region: region,
+ offset: 21,
+ length: 1,
+ explanation: "Changed type 'int' to be nullable",
+ kind: NullabilityFixKind.makeTypeNullable);
+ assertEdit(edit: edits[2], offset: 12, length: 0, replacement: '/*late*/');
+ }
+
+ Future<void> test_addLateHint_classTypedInstanceVariable() async {
+ addMetaPackage();
+ var unit = await buildInfoForSingleTestFile('''
+class C {
+ int f;
+ C() {
+ f = 1;
+ }
+}
+''', migratedContent: '''
+class C {
+ int? f;
+ C() {
+ f = 1;
+ }
+}
+''');
+ var regions = unit.fixRegions;
+ expect(regions, hasLength(1));
+ var region = regions[0];
+ var edits = region.edits;
+ assertRegion(
+ region: region,
+ offset: 15,
+ length: 1,
+ explanation: "Changed type 'int' to be nullable",
+ kind: NullabilityFixKind.makeTypeNullable);
+ assertEdit(edit: edits[2], offset: 12, length: 0, replacement: '/*late*/');
+ }
+
+ Future<void> test_addLateHint_classTypedStaticVariable() async {
+ addMetaPackage();
+ var unit = await buildInfoForSingleTestFile('''
+class C {
+ static int x;
+ void f() => x = null;
+}
+''', migratedContent: '''
+class C {
+ static int? x;
+ void f() => x = null;
+}
+''');
+ var regions = unit.fixRegions;
+ expect(regions, hasLength(1));
+ var region = regions[0];
+ var edits = region.edits;
+ assertRegion(
+ region: region,
+ offset: 22,
+ length: 1,
+ explanation: "Changed type 'int' to be nullable",
+ kind: NullabilityFixKind.makeTypeNullable);
+ assertEdit(edit: edits[2], offset: 19, length: 0, replacement: '/*late*/');
+ }
+
+ Future<void> test_addLateHint_mixinVarInstanceVariable() async {
+ addMetaPackage();
+ var unit = await buildInfoForSingleTestFile('''
+mixin M {
+ int f;
+ void m() => f = null;
+}
+''', migratedContent: '''
+mixin M {
+ int? f;
+ void m() => f = null;
+}
+''');
+ var regions = unit.fixRegions;
+ expect(regions, hasLength(1));
+ var region = regions[0];
+ var edits = region.edits;
+ assertRegion(
+ region: region,
+ offset: 15,
+ length: 1,
+ explanation: "Changed type 'int' to be nullable",
+ kind: NullabilityFixKind.makeTypeNullable);
+ assertEdit(edit: edits[2], offset: 12, length: 0, replacement: '/*late*/');
+ }
+
+ Future<void> test_addLateHint_typedLocalVariable() async {
+ addMetaPackage();
+ var unit = await buildInfoForSingleTestFile('''
+void f() {
+ int x;
+ void g() => x = null;
+}
+''', migratedContent: '''
+void f() {
+ int? x;
+ void g() => x = null;
+}
+''');
+ var regions = unit.fixRegions;
+ expect(regions, hasLength(1));
+ var region = regions[0];
+ var edits = region.edits;
+ assertRegion(
+ region: region,
+ offset: 16,
+ length: 1,
+ explanation: "Changed type 'int' to be nullable",
+ kind: NullabilityFixKind.makeTypeNullable);
+ assertEdit(edit: edits[2], offset: 13, length: 0, replacement: '/*late*/');
+ }
+
+ Future<void> test_addLateHint_typedTopLevelVariable() async {
+ addMetaPackage();
+ var unit = await buildInfoForSingleTestFile('''
+int x;
+void f() => x = null;
+''', migratedContent: '''
+int? x;
+void f() => x = null;
+''');
+ var regions = unit.fixRegions;
+ expect(regions, hasLength(1));
+ var region = regions[0];
+ var edits = region.edits;
+ assertRegion(
+ region: region,
+ offset: 3,
+ length: 1,
+ explanation: "Changed type 'int' to be nullable",
+ kind: NullabilityFixKind.makeTypeNullable);
+ assertEdit(edit: edits[2], offset: 0, length: 0, replacement: '/*late*/');
+ }
+
Future<void> test_compound_assignment_nullable_result() async {
var unit = await buildInfoForSingleTestFile('''
abstract class C {
@@ -1623,7 +1809,7 @@
expect(region.lineNumber, 1);
expect(region.explanation, "Type 'int' was not made nullable");
expect(region.edits.map((edit) => edit.description).toSet(),
- {'Add /*?*/ hint', 'Add /*!*/ hint'});
+ {'Add /*?*/ hint', 'Add /*!*/ hint', 'Add late hint'});
var trace = region.traces.first;
expect(trace.description, 'Non-nullability reason');
var entries = trace.entries;
