Parse NULL column constraints to fix parsing errors (#909)

sqlparser/lib/src/ast/schema/column_definition.dart

@@ -56,6 +56,7 @@ abstract class ColumnConstraint extends AstNode {
 
   T when<T>({
     T Function(NotNull) notNull,
+    T Function(NullColumnConstraint) nullable,
     T Function(PrimaryKeyColumn) primaryKey,
     T Function(UniqueColumn) unique,
     T Function(CheckColumn) check,
@@ -66,6 +67,8 @@ abstract class ColumnConstraint extends AstNode {
   }) {
     if (this is NotNull) {
       return notNull?.call(this as NotNull);
+    } else if (this is NullColumnConstraint) {
+      return nullable?.call(this as NullColumnConstraint);
     } else if (this is PrimaryKeyColumn) {
       return primaryKey?.call(this as PrimaryKeyColumn);
     } else if (this is UniqueColumn) {
@@ -96,6 +99,22 @@ abstract class ColumnConstraint extends AstNode {
 
 enum ConflictClause { rollback, abort, fail, ignore, replace }
 
+class NullColumnConstraint extends ColumnConstraint {
+  /// The `NULL` token forming this constraint.
+  Token $null;
+
+  NullColumnConstraint(String name, {this.$null}) : super(name);
+
+  @override
+  bool _equalToConstraint(NullColumnConstraint other) => true;
+
+  @override
+  Iterable<AstNode> get childNodes => const Iterable.empty();
+
+  @override
+  void transformChildren<A>(Transformer<A> transformer, A arg) {}
+}
+
 class NotNull extends ColumnConstraint {
   final ConflictClause onConflict;
 

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

@@ -436,6 +436,11 @@ mixin SchemaParser on ParserBase {
           autoIncrement: hasAutoInc, mode: mode, onConflict: conflict)
         ..setSpan(first, _previous);
     }
+    if (_matchOne(TokenType.$null)) {
+      final nullToken = _previous;
+      return NullColumnConstraint(resolvedName, $null: nullToken)
+        ..setSpan(nullToken, nullToken);
+    }
     if (_matchOne(TokenType.not)) {
       _suggestHint(HintDescription.token(TokenType.$null));
 

sqlparser/test/common_data.dart

@@ -3,7 +3,7 @@ CREATE TABLE IF NOT EXISTS users (
   id INT NOT NULL PRIMARY KEY DESC ON CONFLICT ROLLBACK AUTOINCREMENT,
   email VARCHAR NOT NULL UNIQUE ON CONFLICT ABORT,
   score INT CONSTRAINT "score set" NOT NULL DEFAULT 420 CHECK (score > 0),
-  display_name VARCHAR COLLATE BINARY 
+  display_name VARCHAR NULL COLLATE BINARY 
      REFERENCES some(thing) ON UPDATE CASCADE ON DELETE SET NULL
      DEFERRABLE INITIALLY DEFERRED,
   

sqlparser/test/parser/create_table_test.dart

@@ -69,6 +69,7 @@ void main() {
             columnName: 'display_name',
             typeName: 'VARCHAR',
             constraints: [
+              NullColumnConstraint(null),
               CollateConstraint(
                 null,
                 'BINARY',

sqlparser/test/parser/regression_909_test.dart

@@ -0,0 +1,24 @@
+import 'package:sqlparser/sqlparser.dart';
+import 'package:test/test.dart';
+
+// ignore_for_file: lines_longer_than_80_chars
+void main() {
+  const stmts = [
+    'CREATE TABLE plots (owner_id VARCHAR NOT NULL, deleted INTEGER NOT NULL, last_synced INTEGER NULL, last_modified INTEGER NOT NULL, id VARCHAR NOT NULL, name VARCHAR NOT NULL, crop VARCHAR NOT NULL, crop_variety VARCHAR NOT NULL, planting_date INTEGER NOT NULL, is_outdoor_trial INTEGER NOT NULL CHECK (is_outdoor_trial in (0, 1)), uses_crop_blanket INTEGER NOT NULL CHECK (uses_crop_blanket in (0, 1)), is_raised_bed INTEGER NOT NULL CHECK (is_raised_bed in (0, 1)), plant_spacing REAL NOT NULL, row_spacing REAL NOT NULL, irrigation_type VARCHAR NOT NULL, rows_per_bed REAL NULL, bed_spacing REAL NULL, coordinates VARCHAR NOT NULL, PRIMARY KEY (id))',
+    'CREATE TABLE lab_reports (owner_id VARCHAR NOT NULL, deleted INTEGER NOT NULL, last_synced INTEGER NULL, last_modified INTEGER NOT NULL, id VARCHAR NOT NULL, sample_date INTEGER NOT NULL, source VARCHAR NOT NULL, PRIMARY KEY (id))',
+    'CREATE TABLE dissipated_active_ingredients (id VARCHAR NOT NULL, lab_report_id VARCHAR NOT NULL, active_ingredient_id VARCHAR NULL, name VARCHAR NULL, residue REAL NOT NULL, PRIMARY KEY (id))',
+    'CREATE TABLE sprays (owner_id VARCHAR NOT NULL, deleted INTEGER NOT NULL, last_synced INTEGER NULL, last_modified INTEGER NOT NULL, id VARCHAR NOT NULL, create_date INTEGER NOT NULL, application_method VARCHAR NOT NULL, growth_stage VARCHAR NOT NULL, PRIMARY KEY (id))',
+    'CREATE TABLE products (id VARCHAR NOT NULL, trade_name VARCHAR NOT NULL, type VARCHAR NOT NULL, owner_id VARCHAR NULL, PRIMARY KEY (id))',
+    'CREATE TABLE markets (owner_id VARCHAR NOT NULL, deleted INTEGER NOT NULL, last_synced INTEGER NULL, last_modified INTEGER NOT NULL, id VARCHAR NOT NULL, name VARCHAR NOT NULL, mrl REAL NOT NULL, arfd REAL NOT NULL, adi REAL NOT NULL, total_active_ingredients INTEGER NOT NULL, PRIMARY KEY (id))',
+  ];
+
+  test('parses statements', () {
+    final engine = SqlEngine();
+
+    for (final stmt in stmts) {
+      final result = engine.parse(stmt);
+      expect(result.errors, isEmpty);
+      expect(result.rootNode, isA<CreateTableStatement>());
+    }
+  });
+}