Make foreign key mapping null safe (#451)

* Change ForeignKeyAction to enum in the generator (#359)

* Added support for WITH statements for DatabaseViews (#443)

* Documentation update on DateTimeConverter sample (#442)

* Make foreign key mapping null safe

Co-authored-by: mqus <8398165+mqus@users.noreply.github.com>
Co-authored-by: themadmrj <themadmrj@users.noreply.github.com>
Co-authored-by: Cássio Seffrin <cassioseffrin@gmail.com>

README.md

@@ -587,12 +587,14 @@ The implementation and usage of the mentioned `DateTime` to `int` converter is d
 class DateTimeConverter extends TypeConverter<DateTime, int> {
   @override
   DateTime decode(int databaseValue) {
-    return DateTime.fromMillisecondsSinceEpoch(databaseValue);
+    return databaseValue == null
+        ? null
+        : DateTime.fromMillisecondsSinceEpoch(databaseValue);
   }
 
   @override
   int encode(DateTime value) {
-    return value.millisecondsSinceEpoch;
+    return value == null ? null : value.millisecondsSinceEpoch;
   }
 }
 ```

floor/README.md

@@ -584,12 +584,14 @@ The implementation and usage of the mentioned `DateTime` to `int` converter is d
 class DateTimeConverter extends TypeConverter<DateTime, int> {
   @override
   DateTime decode(int databaseValue) {
-    return DateTime.fromMillisecondsSinceEpoch(databaseValue);
+    return databaseValue == null
+        ? null
+        : DateTime.fromMillisecondsSinceEpoch(databaseValue);
   }
 
   @override
   int encode(DateTime value) {
-    return value.millisecondsSinceEpoch;
+    return value == null ? null : value.millisecondsSinceEpoch;
   }
 }
 ```

floor_annotation/lib/src/foreign_key.dart

@@ -13,13 +13,13 @@ class ForeignKey {
   /// Action to take when the parent [Entity] is updated from the database.
   ///
   /// By default, [ForeignKeyAction.noAction] is used.
-  final int onUpdate;
+  final ForeignKeyAction onUpdate;
 
   /// [ForeignKeyAction]
   /// Action to take when the parent [Entity] is deleted from the database.
   ///
   /// By default, [ForeignKeyAction.noAction] is used.
-  final int onDelete;
+  final ForeignKeyAction onDelete;
 
   /// Declares a foreign key on another [Entity].
   const ForeignKey({
@@ -33,13 +33,13 @@ class ForeignKey {
 
 /// Constants definition for values that can be used in
 /// [ForeignKey.onDelete] and [ForeignKey.onUpdate]
-abstract class ForeignKeyAction {
+enum ForeignKeyAction {
   /// Possible value for [ForeignKey.onDelete] or [ForeignKey.onUpdate].
   ///
   /// When a parent key is modified or deleted from the database, no special
   /// action is taken. This means that SQLite will not make any effort to fix
   /// the constraint failure, instead, reject the change.
-  static const noAction = 1;
+  noAction,
 
   /// Possible value for [ForeignKey.onDelete] or [ForeignKey.onUpdate].
   ///
@@ -55,22 +55,22 @@ abstract class ForeignKeyAction {
   /// Even if the foreign key constraint it is attached to is deferred(),
   /// configuring a RESTRICT action causes SQLite to return an error immediately
   /// if a parent key with dependent child keys is deleted or modified.
-  static const restrict = 2;
+  restrict,
 
   /// Possible value for [ForeignKey.onDelete] or [ForeignKey.onUpdate].
   ///
   /// If the configured action is 'SET NULL', then when a parent key is deleted
   /// (for [ForeignKey.onDelete]) or modified (for [ForeignKey.onUpdate]), the
   /// child key columns of all rows in the child table that mapped to the parent
   /// key are set to contain NULL values.
-  static const setNull = 3;
+  setNull,
 
   /// Possible value for [ForeignKey.onDelete] or [ForeignKey.onUpdate].
   ///
   /// The 'SET DEFAULT' actions are similar to SET_NULL, except that each of the
   /// child key columns is set to contain the columns default value instead of
   /// NULL.
-  static const setDefault = 4;
+  setDefault,
 
   /// Possible value for [ForeignKey.onDelete] or [ForeignKey.onUpdate].
   ///
@@ -80,5 +80,5 @@ abstract class ForeignKeyAction {
   /// deleted parent row is also deleted. For an [ForeignKey.onUpdate] action,
   /// it means that the values stored in each dependent child key are modified
   /// to match the new parent key values.
-  static const cascade = 5;
+  cascade,
 }

floor_generator/lib/misc/extension/dart_object_extension.dart

@@ -2,16 +2,35 @@
 // ignore_for_file: import_of_legacy_library_into_null_safe
 import 'package:analyzer/dart/constant/value.dart';
 import 'package:analyzer/dart/element/type.dart';
+import 'package:collection/collection.dart';
+import 'package:floor_annotation/floor_annotation.dart';
 
 extension DartObjectExtension on DartObject {
-  String toEnumValueString() {
+  /// get the String representation of the enum value,
+  /// or `null` if the enum was not valid
+  String? toEnumValueString() {
     final interfaceType = type as InterfaceType;
     final enumName = interfaceType.getDisplayString(withNullability: false);
     final enumValue = interfaceType.element.fields
         .where((element) => element.isEnumConstant)
         .map((fieldElement) => fieldElement.name)
-        .singleWhere((valueName) => getField(valueName) != null);
+        .singleWhereOrNull((valueName) => getField(valueName) != null);
+    if (enumValue == null) {
+      return null;
+    } else {
+      return '$enumName.$enumValue';
+    }
+  }
 
-    return '$enumName.$enumValue';
+  /// get the ForeignKeyAction this enum represents,
+  /// or the result of `null` if the enum did not contain a valid value
+  ForeignKeyAction? toForeignKeyAction() {
+    final enumValueString = toEnumValueString();
+    if (enumValueString == null) {
+      return null;
+    } else {
+      return ForeignKeyAction.values.singleWhereOrNull(
+          (foreignKeyAction) => foreignKeyAction.toString() == enumValueString);
+    }
   }
 }

floor_generator/lib/misc/extension/foreign_key_action_extension.dart

@@ -0,0 +1,18 @@
+import 'package:floor_annotation/floor_annotation.dart';
+
+extension ForeignKeyActionExtension on ForeignKeyAction {
+  String toSql() {
+    switch (this) {
+      case ForeignKeyAction.noAction:
+        return 'NO ACTION';
+      case ForeignKeyAction.restrict:
+        return 'RESTRICT';
+      case ForeignKeyAction.setNull:
+        return 'SET NULL';
+      case ForeignKeyAction.setDefault:
+        return 'SET DEFAULT';
+      case ForeignKeyAction.cascade:
+        return 'CASCADE';
+    }
+  }
+}

floor_generator/lib/processor/entity_processor.dart

@@ -5,9 +5,9 @@ import 'package:analyzer/dart/element/element.dart';
 import 'package:collection/collection.dart';
 import 'package:floor_annotation/floor_annotation.dart' as annotations;
 import 'package:floor_generator/misc/constants.dart';
+import 'package:floor_generator/misc/extension/dart_object_extension.dart';
 import 'package:floor_generator/misc/extension/string_extension.dart';
 import 'package:floor_generator/misc/extension/type_converters_extension.dart';
-import 'package:floor_generator/misc/foreign_key_action.dart';
 import 'package:floor_generator/misc/type_utils.dart';
 import 'package:floor_generator/processor/error/entity_processor_error.dart';
 import 'package:floor_generator/processor/queryable_processor.dart';
@@ -91,13 +91,11 @@ class EntityProcessor extends QueryableProcessor<Entity> {
             throw _processorError.missingParentColumns;
           }
 
-          final onUpdateAnnotationValue =
-              foreignKeyObject.getField(ForeignKeyField.onUpdate)?.toIntValue();
-          final onUpdate = ForeignKeyAction.getString(onUpdateAnnotationValue);
+          final onUpdate =
+              _getForeignKeyAction(foreignKeyObject, ForeignKeyField.onUpdate);
 
-          final onDeleteAnnotationValue =
-              foreignKeyObject.getField(ForeignKeyField.onDelete)?.toIntValue();
-          final onDelete = ForeignKeyAction.getString(onDeleteAnnotationValue);
+          final onDelete =
+              _getForeignKeyAction(foreignKeyObject, ForeignKeyField.onDelete);
 
           return ForeignKey(
             parentName,
@@ -261,4 +259,24 @@ class EntityProcessor extends QueryableProcessor<Entity> {
       return attributeValue;
     }
   }
+
+  annotations.ForeignKeyAction _getForeignKeyAction(
+    DartObject foreignKeyObject,
+    String triggerName,
+  ) {
+    final field = foreignKeyObject.getField(triggerName);
+    // TODO #375 remove suppress when getField is null aware
+    // ignore: unnecessary_null_comparison
+    if (field == null) {
+      // field was not defined, return default value
+      return annotations.ForeignKeyAction.noAction;
+    }
+
+    final foreignKeyAction = field.toForeignKeyAction();
+    if (foreignKeyAction == null) {
+      throw _processorError.wrongForeignKeyAction(field, triggerName);
+    } else {
+      return foreignKeyAction;
+    }
+  }
 }

floor_generator/lib/processor/error/entity_processor_error.dart

@@ -1,5 +1,6 @@
 // TODO #375 delete once dependencies have migrated
 // ignore_for_file: import_of_legacy_library_into_null_safe
+import 'package:analyzer/dart/constant/value.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:source_gen/source_gen.dart';
 
@@ -71,6 +72,16 @@ class EntityProcessorError {
     );
   }
 
+  InvalidGenerationSourceError wrongForeignKeyAction(
+      DartObject field, String triggerName) {
+    return InvalidGenerationSourceError(
+      'No ForeignKeyAction with the value $field exists for the $triggerName trigger.',
+      todo:
+          'Make sure to add a correct ForeignKeyAction like `ForeignKeyAction.noAction` or leave it out entirely.',
+      element: _classElement,
+    );
+  }
+
   InvalidGenerationSourceError get autoIncrementInWithoutRowid {
     return InvalidGenerationSourceError(
       'autoGenerate is not allowed in WITHOUT ROWID tables',

floor_generator/lib/processor/insertion_method_processor.dart

@@ -3,7 +3,7 @@
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:floor_annotation/floor_annotation.dart' as annotations
-    show Insert;
+    show Insert, OnConflictStrategy;
 import 'package:floor_generator/misc/change_method_processor_helper.dart';
 import 'package:floor_generator/misc/constants.dart';
 import 'package:floor_generator/misc/extension/dart_object_extension.dart';
@@ -79,10 +79,19 @@ class InsertionMethodProcessor implements Processor<InsertionMethod> {
   }
 
   String _getOnConflictStrategy() {
-    return _methodElement
+    final onConflictStrategy = _methodElement
         .getAnnotation(annotations.Insert)
         .getField(AnnotationField.onConflict)
         .toEnumValueString();
+
+    if (onConflictStrategy == null) {
+      throw InvalidGenerationSourceError(
+        'Value of ${AnnotationField.onConflict} must be one of ${annotations.OnConflictStrategy.values.map((e) => e.toString()).join(',')}',
+        element: _methodElement,
+      );
+    } else {
+      return onConflictStrategy;
+    }
   }
 
   void _assertMethodReturnsFuture(final DartType returnType) {

floor_generator/lib/processor/update_method_processor.dart

@@ -3,7 +3,7 @@
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:floor_annotation/floor_annotation.dart' as annotations
-    show Update;
+    show Update, OnConflictStrategy;
 import 'package:floor_generator/misc/change_method_processor_helper.dart';
 import 'package:floor_generator/misc/constants.dart';
 import 'package:floor_generator/misc/extension/dart_object_extension.dart';
@@ -63,10 +63,19 @@ class UpdateMethodProcessor implements Processor<UpdateMethod> {
   }
 
   String _getOnConflictStrategy() {
-    return _methodElement
+    final onConflictStrategy = _methodElement
         .getAnnotation(annotations.Update)
         .getField(AnnotationField.onConflict)
         .toEnumValueString();
+
+    if (onConflictStrategy == null) {
+      throw InvalidGenerationSourceError(
+        'Value of ${AnnotationField.onConflict} must be one of ${annotations.OnConflictStrategy.values.map((e) => e.toString()).join(',')}',
+        element: _methodElement,
+      );
+    } else {
+      return onConflictStrategy;
+    }
   }
 
   DartType _getFlattenedReturnType(final DartType returnType) {

floor_generator/lib/processor/view_processor.dart

@@ -44,9 +44,21 @@ class ViewProcessor extends QueryableProcessor<View> {
         .getField(AnnotationField.viewQuery)
         ?.toStringValue();
 
-    if (query == null || !query.trimLeft().toLowerCase().startsWith('select')) {
+    if (query == null || !(query.isSelectQuery || query.isCteWithSelect)) {
       throw _processorError.missingQuery;
     }
     return query;
   }
 }
+
+extension on String {
+  bool get isSelectQuery => toLowerCase().trimLeft().startsWith('select');
+
+  /// whether the string is a common table expression
+  /// followed by a `SELECT` query
+  bool get isCteWithSelect {
+    final lowerCasedString = toLowerCase();
+    return lowerCasedString.trimLeft().startsWith('with') &&
+        'select'.allMatches(lowerCasedString).length >= 2;
+  }
+}

floor_generator/lib/value_object/foreign_key.dart

@@ -1,13 +1,15 @@
 // TODO #375 delete once dependencies have migrated
 // ignore_for_file: import_of_legacy_library_into_null_safe
 import 'package:collection/collection.dart';
+import 'package:floor_annotation/floor_annotation.dart' show ForeignKeyAction;
+import 'package:floor_generator/misc/extension/foreign_key_action_extension.dart';
 
 class ForeignKey {
   final String parentName;
   final List<String> parentColumns;
   final List<String> childColumns;
-  final String onUpdate;
-  final String onDelete;
+  final ForeignKeyAction onUpdate;
+  final ForeignKeyAction onDelete;
 
   ForeignKey(
     this.parentName,
@@ -25,8 +27,8 @@ class ForeignKey {
 
     return 'FOREIGN KEY ($escapedChildColumns)'
         ' REFERENCES `$parentName` ($escapedParentColumns)'
-        ' ON UPDATE $onUpdate'
-        ' ON DELETE $onDelete';
+        ' ON UPDATE ${onUpdate.toSql()}'
+        ' ON DELETE ${onDelete.toSql()}';
   }
 
   final _listEquality = const ListEquality<String>();