Don't write variables in `CREATE VIEW`

drift/CHANGELOG.md

@@ -3,6 +3,7 @@
 - Add `DataClassName.extending` to control the superclass of generated row
   classes.
 - Add `setup` parameter to the constructors of `WebDatabase` too.
+- Don't write variables for expressions in `CREATE VIEW` statements.
 
 ## 1.4.0
 

drift/lib/src/runtime/query_builder/expressions/variables.dart

@@ -60,6 +60,12 @@ class Variable<T> extends Expression<T> {
 
   @override
   void writeInto(GenerationContext context) {
+    if (!context.supportsVariables) {
+      // Write as constant instead.
+      Constant<T>(value).writeInto(context);
+      return;
+    }
+
     var explicitStart = context.explicitVariableIndex;
 
     var mark = '?';

drift/lib/src/runtime/query_builder/generation_context.dart

@@ -30,6 +30,12 @@ class GenerationContext {
   /// query.
   final DatabaseConnectionUser? executor;
 
+  /// Whether variables are supported and can be written as `?` to be bound
+  /// later.
+  ///
+  /// This is almost always the case, but not in a `CREATE VIEW` statement.
+  final bool supportsVariables;
+
   final List<dynamic> _boundVariables = [];
 
   /// The values of [introducedVariables] that will be sent to the underlying
@@ -51,7 +57,7 @@ class GenerationContext {
 
   /// Constructs a [GenerationContext] by copying the relevant fields from the
   /// database.
-  GenerationContext.fromDb(this.executor)
+  GenerationContext.fromDb(this.executor, {this.supportsVariables = true})
       : typeSystem = executor?.typeSystem ?? SqlTypeSystem.defaultInstance,
         // ignore: invalid_null_aware_operator, (doesn't seem to actually work)
         dialect = executor?.executor?.dialect ?? SqlDialect.sqlite;
@@ -59,7 +65,7 @@ class GenerationContext {
   /// Constructs a custom [GenerationContext] by setting the fields manually.
   /// See [GenerationContext.fromDb] for a more convenient factory.
   GenerationContext(this.typeSystem, this.executor,
-      {this.dialect = SqlDialect.sqlite});
+      {this.dialect = SqlDialect.sqlite, this.supportsVariables = true});
 
   /// Introduces a variable that will be sent to the database engine. Whenever
   /// this method is called, a question mark should be added to the [buffer] so

drift/lib/src/runtime/query_builder/migration.dart

@@ -324,7 +324,7 @@ class Migrator {
     if (stmt != null) {
       await _issueCustomQuery(stmt, const []);
     } else if (view.query != null) {
-      final context = GenerationContext.fromDb(_db);
+      final context = GenerationContext.fromDb(_db, supportsVariables: false);
       context.generatingForView = view.entityName;
       context.buffer.write('CREATE VIEW IF NOT EXISTS ${view.entityName} AS ');
       view.query!.writeInto(context);

drift/test/data/tables/todos.dart

@@ -121,10 +121,12 @@ abstract class CategoryTodoCountView extends View {
   TodosTable get todos;
   Categories get categories;
 
+  Expression<String> get description =>
+      categories.description + const Variable('!');
   Expression<int> get itemCount => todos.id.count();
 
   @override
-  Query as() => select([categories.description, itemCount])
+  Query as() => select([description, itemCount])
       .from(categories)
       .join([innerJoin(todos, todos.category.equalsExp(categories.id))]);
 }

drift/test/data/tables/todos.g.dart

@@ -1362,7 +1362,7 @@ class CategoryTodoCountViewData extends DataClass {
     final effectivePrefix = prefix ?? '';
     return CategoryTodoCountViewData(
       description: const StringType()
-          .mapFromDatabaseResponse(data['${effectivePrefix}categories.desc'])!,
+          .mapFromDatabaseResponse(data['${effectivePrefix}description'])!,
       itemCount: const IntType()
           .mapFromDatabaseResponse(data['${effectivePrefix}item_count'])!,
     );
@@ -1423,7 +1423,7 @@ class $CategoryTodoCountViewView
   $TodosTableTable get todos => attachedDatabase.todosTable;
   $CategoriesTable get categories => attachedDatabase.categories;
   @override
-  List<GeneratedColumn> get $columns => [categories.description, itemCount];
+  List<GeneratedColumn> get $columns => [description, itemCount];
   @override
   String get aliasedName => _alias ?? entityName;
   @override
@@ -1440,8 +1440,10 @@ class $CategoryTodoCountViewView
   }
 
   late final GeneratedColumn<String?> description = GeneratedColumn<String?>(
-      'desc', aliasedName, false,
-      type: const StringType(), $customConstraints: 'NOT NULL UNIQUE');
+      'description', aliasedName, false,
+      type: const StringType(),
+      generatedAs:
+          GeneratedAs(categories.description + const Variable('!'), false));
   late final GeneratedColumn<int?> itemCount = GeneratedColumn<int?>(
       'item_count', aliasedName, false,
       type: const IntType(), generatedAs: GeneratedAs(todos.id.count(), false));

drift/test/expressions/variable_test.dart

@@ -54,7 +54,15 @@ void main() {
 
     variable.writeInto(ctx);
 
-    expect('NULL', ctx.sql);
+    expect(ctx.sql, 'NULL');
     expect(ctx.boundVariables, isEmpty);
   });
+
+  test('writes constants when variables are not supported', () {
+    const variable = Variable<String?>("hello world'");
+    final ctx = GenerationContext.fromDb(TodoDb(), supportsVariables: false);
+    variable.writeInto(ctx);
+
+    expect(ctx.sql, "'hello world'''");
+  });
 }

drift/test/schema_test.dart

@@ -67,7 +67,7 @@ void main() {
 
       verify(mockExecutor.runCustom(
           'CREATE VIEW IF NOT EXISTS category_todo_count_view AS SELECT '
-          'categories."desc" AS "categories.desc", '
+          'categories."desc" || \'!\' AS "description", '
           'COUNT(todos.id) AS "item_count" '
           'FROM categories '
           'INNER JOIN todos '