[DAS] Adds fixes for required named parameters

Bug: #53707
Fixes: #60783

Change-Id: I62646bd1ac5805fb9030eda712064ec7d8c253b9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/422369
Reviewed-by: Konstantin Shcheglov <[email protected]>
Reviewed-by: Samuel Rawlins <[email protected]>
Auto-Submit: Felipe Morschel <[email protected]>
Commit-Queue: Samuel Rawlins <[email protected]>

Author: FMorschel

pkg/analysis_server/lib/src/services/correction/dart/add_field_formal_parameters.dart

@@ -7,21 +7,34 @@ import 'package:analysis_server_plugin/edit/dart/correction_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/error_verifier.dart';
-import 'package:analyzer/src/utilities/extensions/flutter.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 
+/// The boolean value indicates whether the field is required.
+/// The string value is the field/parameter name.
+typedef _FieldRecord = ({bool isRequired, String parameter});
+
 class AddFieldFormalParameters extends ResolvedCorrectionProducer {
-  AddFieldFormalParameters({required super.context});
+  final _Style _style;
+
+  bool _useRequired = false;
+
+  @override
+  final FixKind fixKind;
+
+  AddFieldFormalParameters({required super.context})
+    : _style = _Style.base,
+      fixKind = DartFixKind.ADD_INITIALIZING_FORMAL_PARAMETERS;
+
+  AddFieldFormalParameters.requiredNamed({required super.context})
+    : _style = _Style.requiredNamed,
+      fixKind = DartFixKind.ADD_INITIALIZING_FORMAL_NAMED_PARAMETERS;
 
   @override
   CorrectionApplicability get applicability =>
       // TODO(applicability): comment on why.
       CorrectionApplicability.singleLocation;
 
-  @override
-  FixKind get fixKind => DartFixKind.ADD_INITIALIZING_FORMAL_PARAMETERS;
-
   @override
   Future<void> compute(ChangeBuilder builder) async {
     var constructor = node.parent;
@@ -47,43 +60,73 @@ class AddFieldFormalParameters extends ResolvedCorrectionProducer {
       (a, b) => a.firstFragment.nameOffset! - b.firstFragment.nameOffset!,
     );
 
-    // Specialize for Flutter widgets.
-    if (superType.isExactlyStatelessWidgetType ||
-        superType.isExactlyStatefulWidgetType) {
-      if (parameters.isNotEmpty && parameters.last.isNamed) {
-        String parameterForField(FieldElement field) {
-          var prefix = '';
-          if (typeSystem.isPotentiallyNonNullable(field.type)) {
-            prefix = 'required ';
-          }
-          return '${prefix}this.${field.name}';
-        }
-
-        var fieldParametersCode = fields.map(parameterForField).join(', ');
-        await builder.addDartFileEdit(file, (builder) {
-          builder.addSimpleInsertion(
-            parameters.last.end,
-            ', $fieldParametersCode',
-          );
-        });
-        return;
-      }
-    }
-
     // Prepare the last required parameter.
     FormalParameter? lastRequiredParameter;
+    FormalParameter? firstNamedParameter;
     for (var parameter in parameters) {
       if (parameter.isRequiredPositional) {
         lastRequiredParameter = parameter;
+      } else if (_style == _Style.base) {
+        break;
+      } else if (parameter.isOptionalPositional) {
+        // If there are optional positional parameters, we can't add required
+        // named parameters.
+        return;
+      } else if (parameter.isNamed) {
+        firstNamedParameter = parameter;
+        break;
       }
     }
 
-    var fieldParametersCode = fields
-        .map((field) => 'this.${field.name}')
-        .join(', ');
+    if (_style == _Style.requiredNamed) {
+      _useRequired = true;
+    }
+
+    var fieldsRecords = fields.map(_parameterForField).toList();
+    var requiredFirst =
+        getCodeStyleOptions(unitResult.file).requiredNamedParametersFirst;
+    if (requiredFirst) {
+      fieldsRecords.sort((a, b) {
+        if (a.isRequired && !b.isRequired) {
+          return -1;
+        } else if (!a.isRequired && b.isRequired) {
+          return 1;
+        }
+        return a.parameter.compareTo(b.parameter);
+      });
+    }
+    var requiredParameters = fieldsRecords.where((r) => r.isRequired);
+    var optionalParameters = fieldsRecords
+        .where((r) => !r.isRequired)
+        .map((r) => r.parameter);
+    var fieldParametersCode = fieldsRecords.map((r) => r.parameter).join(', ');
     await builder.addDartFileEdit(file, (builder) {
-      if (lastRequiredParameter != null) {
+      if (firstNamedParameter != null &&
+          requiredFirst &&
+          requiredParameters.isNotEmpty) {
         builder.addSimpleInsertion(
+          firstNamedParameter.offset,
+          '${requiredParameters.map((r) => r.parameter).join(', ')}, ',
+        );
+        if (optionalParameters.isNotEmpty) {
+          fieldParametersCode = optionalParameters.join(', ');
+        } else {
+          return; // No optional parameters to add.
+        }
+      }
+      if (_style == _Style.requiredNamed) {
+        var lastParameter = parameters.lastOrNull;
+        if (lastParameter != null) {
+          var write = ', ';
+          if (!lastParameter.isNamed) {
+            write += '{$fieldParametersCode}';
+          } else {
+            write += fieldParametersCode;
+          }
+          builder.addSimpleInsertion(parameters.last.end, write);
+        }
+      } else if (lastRequiredParameter != null) {
+        return builder.addSimpleInsertion(
           lastRequiredParameter.end,
           ', $fieldParametersCode',
         );
@@ -96,4 +139,16 @@ class AddFieldFormalParameters extends ResolvedCorrectionProducer {
       }
     });
   }
+
+  _FieldRecord _parameterForField(FieldElement field) {
+    var prefix = '';
+    var isRequired = false;
+    if (typeSystem.isPotentiallyNonNullable(field.type) && _useRequired) {
+      isRequired = true;
+      prefix = 'required ';
+    }
+    return (isRequired: isRequired, parameter: '${prefix}this.${field.name}');
+  }
 }
+
+enum _Style { base, requiredNamed }