Make order by placeholders optional (#998)

moor/lib/src/runtime/api/connection_user.dart

@@ -437,14 +437,7 @@ abstract class DatabaseConnectionUser {
     if (hasMultipleTables != null) {
       context.hasMultipleTables = hasMultipleTables;
     }
-
-    // we don't want ORDER BY clauses to write the ORDER BY tokens because those
-    // are already declared in sql
-    if (component is OrderBy) {
-      component.writeInto(context, writeOrderBy: false);
-    } else {
     component.writeInto(context);
-    }
 
     return context;
   }

moor/lib/src/runtime/query_builder/components/order_by.dart

@@ -56,14 +56,18 @@ class OrderBy extends Component {
   final List<OrderingTerm> terms;
 
   /// Constructs an order by clause by the [terms].
-  OrderBy(this.terms);
+  const OrderBy(this.terms);
+
+  /// Orders by nothing.
+  ///
+  /// In this case, the ordering of result rows is undefined.
+  const OrderBy.nothing() : this(const []);
 
   @override
-  void writeInto(GenerationContext context, {bool writeOrderBy = true}) {
-    if (writeOrderBy) {
-      context.buffer.write('ORDER BY ');
-    }
+  void writeInto(GenerationContext context) {
+    if (terms.isEmpty) return;
 
+    context.buffer.write('ORDER BY ');
     _writeCommaSeparated(context, terms);
   }
 }

moor/lib/src/runtime/query_builder/query_builder.dart

@@ -46,6 +46,9 @@ part 'migration.dart';
 
 /// A component is anything that can appear in a sql query.
 abstract class Component {
+  /// Default, constant constructor.
+  const Component();
+
   /// Writes this component into the [context] by writing to its
   /// [GenerationContext.buffer] or by introducing bound variables. When writing
   /// into the buffer, no whitespace around the this component should be

moor/test/data/tables/custom_tables.g.dart

@@ -1589,14 +1589,14 @@ abstract class _$CustomTablesDb extends GeneratedDatabase {
   }
 
   Selectable<Config> readMultiple(List<String> var1,
-      {required OrderBy clause}) {
+      {OrderBy clause = const OrderBy.nothing()}) {
     var $arrayStartIndex = 1;
     final expandedvar1 = $expandVar($arrayStartIndex, var1.length);
     $arrayStartIndex += var1.length;
     final generatedclause = $write(clause);
     $arrayStartIndex += generatedclause.amountOfVariables;
     return customSelect(
-        'SELECT * FROM config WHERE config_key IN ($expandedvar1) ORDER BY ${generatedclause.sql}',
+        'SELECT * FROM config WHERE config_key IN ($expandedvar1) ${generatedclause.sql}',
         variables: [
           for (var $ in var1) Variable<String>($),
           ...generatedclause.introducedVariables

moor/test/parsed_sql/moor_files_integration_test.dart

@@ -131,6 +131,11 @@ void main() {
     verify(mock.runSelect(argThat(contains('with_defaults.a')), any));
   });
 
+  test('order by-params are ignored by default', () async {
+    await db.readMultiple(['foo']).get();
+    verify(mock.runSelect(argThat(isNot(contains('with_defaults.a'))), any));
+  });
+
   test('runs queries with nested results', () async {
     const row = {
       'a': 'text for a',

moor_generator/lib/src/analyzer/options.g.dart

@@ -93,6 +93,7 @@ MoorOptions _$MoorOptionsFromJson(Map<String, dynamic> json) {
     'modules': 'sqlite_modules',
     'rawResultSetData': 'raw_result_set_data',
     'generateValuesInCopyWith': 'generate_values_in_copy_with',
+    'generateNamedParameters': 'named_parameters',
   });
 }
 

moor_generator/lib/src/writer/queries/query_writer.dart

@@ -250,7 +250,7 @@ class QueryWriter {
     var needsComma = false;
     for (final element in query.elements) {
       // Placeholders with a default value generate optional (and thus, named)
-      // parameters. Since moor 3.5, we have an option to also generate named
+      // parameters. Since moor 4, we have an option to also generate named
       // parameters for named variables.
       final isNamed =
           (element is FoundDartPlaceholder && element.defaultValue != null) ||
@@ -277,23 +277,34 @@ class QueryWriter {
         if (needsComma) _buffer.write(', ');
         needsComma = true;
 
-        final type = optional.dartTypeCode(scope.generationOptions);
-        if (optional is FoundDartPlaceholder && optional.defaultValue != null) {
-          // Wrap the default expression in parentheses to avoid issues with the
-          // surrounding precedence in SQL.
+        String defaultCode;
+
+        if (optional is FoundDartPlaceholder) {
+          final kind = optional.type;
+          if (kind == DartPlaceholderType.expression &&
+              optional.defaultValue != null) {
+            // Wrap the default expression in parentheses to avoid issues with
+            // the surrounding precedence in SQL.
             final defaultSql =
                 "'(${escapeForDart(optional.defaultValue.toSql())})'";
-          _buffer.write('$type ${optional.dartParameterName} = '
-              'const CustomExpression($defaultSql)');
-        } else {
+            defaultCode = 'const CustomExpression($defaultSql)';
+          } else if (kind == DartPlaceholderType.orderBy) {
+            defaultCode = 'const OrderBy.nothing()';
+          }
+        }
+
+        final type = optional.dartTypeCode(scope.generationOptions);
+
         // No default value, this element is required if it's not nullable
-          final isNullable =
-              optional is FoundVariable && optional.nullableInDart;
-          if (!isNullable) {
+        final isNullable = optional is FoundVariable && optional.nullableInDart;
+        final isRequired = !isNullable && defaultCode == null;
+        if (isRequired) {
           _buffer..write(scope.required)..write(' ');
         }
 
         _buffer.write('$type ${optional.dartParameterName}');
+        if (defaultCode != null) {
+          _buffer..write(' =  ')..write(defaultCode);
         }
       }
 

sqlparser/lib/src/reader/parser/crud.dart

@@ -478,7 +478,7 @@ mixin CrudParser on ParserBase {
       if (terms.length == 1 && terms.single is DartOrderingTermPlaceholder) {
         final termPlaceholder = terms.single as DartOrderingTermPlaceholder;
         return DartOrderByPlaceholder(name: termPlaceholder.name)
-          ..setSpan(termPlaceholder.first!, termPlaceholder.last!);
+          ..setSpan(orderToken, termPlaceholder.last!);
       }
 
       return OrderBy(terms: terms)..setSpan(orderToken, _previous);