Distinguish between SQL null and JSON null in JSONB[]. (#450)

Author: isoos

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 3.5.11
+
+- Adding `JsonbListView` with `isSqlNull(int index)` method to check if a JSONB array has SQL or JSON null value.
+
 ## 3.5.10
 
 - Supporting `BYTEA[]` built-in type.

lib/src/types.dart

@@ -3,6 +3,7 @@ import 'dart:core' as core;
 import 'dart:core';
 import 'dart:typed_data';
 
+import 'package:collection/collection.dart';
 import 'package:meta/meta.dart';
 
 import 'types/generic_type.dart';
@@ -469,3 +470,29 @@ class TypedValue<T extends Object> {
     return 'TypedValue($type, $value)';
   }
 }
+
+/// A decoded PostgreSQL `jsonb[]` array.
+///
+/// Wraps the list of decoded JSON values and tracks which elements were SQL
+/// `NULL` (as opposed to the JSON `null` literal, which also decodes to Dart
+/// `null` but is a non-null value at the SQL level).
+///
+/// Use [isSqlNull] to distinguish between the two:
+/// ```dart
+/// final list = row[0] as JsonbListView;
+/// list[0];              // null — but is it SQL NULL or JSON null?
+/// list.isSqlNull(0);    // true  → SQL NULL  (IS NULL in SQL)
+/// list.isSqlNull(1);    // false → JSON null ('null'::jsonb, IS NOT NULL in SQL)
+/// ```
+class JsonbListView extends UnmodifiableListView<Object?> {
+  final List<bool> _sqlNulls;
+
+  JsonbListView(super.items, List<bool> sqlNulls) : _sqlNulls = sqlNulls;
+
+  /// Returns `true` if the element at [index] was a SQL `NULL` in the array
+  /// (i.e. the PostgreSQL wire protocol sent a -1 length sentinel).
+  ///
+  /// Returns `false` for elements that carry an actual value, including the
+  /// JSON `null` literal (`'null'::jsonb`), which also decodes to Dart `null`.
+  bool isSqlNull(int index) => _sqlNulls[index];
+}

lib/src/types/binary_codec.dart

@@ -583,9 +583,11 @@ class PostgresBinaryEncoder {
       case TypeOid.jsonbArray:
         {
           if (input is List) {
-            final objectsArray = input
-                .map(_jsonFusedEncoding(encoding).encode)
-                .toList();
+            final encoder = _jsonFusedEncoding(encoding);
+            final objectsArray = input.map((item) {
+              if (item is TypedValue && item.isSqlNull) return null;
+              return encoder.encode(item);
+            }).toList();
             return _writeListBytes<List<int>>(
               objectsArray,
               3802,
@@ -914,15 +916,15 @@ class PostgresBinaryDecoder {
         return readListBytes<Uint8List>(
           input,
           (reader, length) => reader.read(length),
-        );
+        ).items;
 
       case TypeOid.uuid:
         return _decodeUuid(input);
       case TypeOid.uuidArray:
         return readListBytes<String>(
           input,
           (reader, _) => _decodeUuid(reader.read(16)),
-        );
+        ).items;
 
       case TypeOid.regtype:
         final data = input.buffer.asByteData(input.offsetInBytes, input.length);
@@ -984,53 +986,66 @@ class PostgresBinaryDecoder {
         return readListBytes<bool>(
           input,
           (reader, _) => reader.readUint8() != 0,
-        );
+        ).items;
 
       case TypeOid.smallIntegerArray:
-        return readListBytes<int>(input, (reader, _) => reader.readInt16());
+        return readListBytes<int>(
+          input,
+          (reader, _) => reader.readInt16(),
+        ).items;
       case TypeOid.integerArray:
-        return readListBytes<int>(input, (reader, _) => reader.readInt32());
+        return readListBytes<int>(
+          input,
+          (reader, _) => reader.readInt32(),
+        ).items;
       case TypeOid.bigIntegerArray:
-        return readListBytes<int>(input, (reader, _) => reader.readInt64());
+        return readListBytes<int>(
+          input,
+          (reader, _) => reader.readInt64(),
+        ).items;
 
       case TypeOid.dateArray:
         return readListBytes<DateTime>(
           input,
           (reader, _) =>
               DateTime.utc(2000).add(Duration(days: reader.readInt32())),
-        );
+        ).items;
       case TypeOid.timeArray:
         return readListBytes<Time>(
           input,
           (reader, _) => Time.fromMicroseconds(reader.readInt64()),
-        );
+        ).items;
       case TypeOid.timestampArray:
       case TypeOid.timestampTzArray:
         return readListBytes<DateTime>(
           input,
           (reader, _) => DateTime.utc(
             2000,
           ).add(Duration(microseconds: reader.readInt64())),
-        );
+        ).items;
 
       case TypeOid.varCharArray:
       case TypeOid.textArray:
         return readListBytes<String>(input, (reader, length) {
           return context.encoding.decode(length > 0 ? reader.read(length) : []);
-        });
+        }).items;
 
       case TypeOid.doubleArray:
         return readListBytes<double>(
           input,
           (reader, _) => reader.readFloat64(),
-        );
+        ).items;
 
       case TypeOid.jsonbArray:
-        return readListBytes<dynamic>(input, (reader, length) {
+        final (:items, :sqlNulls) = readListBytes<dynamic>(input, (
+          reader,
+          length,
+        ) {
           reader.read(1);
           final bytes = reader.read(length - 1);
           return _jsonFusedEncoding(context.encoding).decode(bytes);
         });
+        return JsonbListView(items, sqlNulls);
 
       case TypeOid.integerRange:
         final range = _decodeRange(context, buffer, input, TypeOid.integer);
@@ -1076,12 +1091,12 @@ class PostgresBinaryDecoder {
     );
   }
 
-  static List<V?> readListBytes<V>(
+  static ({List<V?> items, List<bool> sqlNulls}) readListBytes<V>(
     Uint8List data,
     V Function(ByteDataReader reader, int length) valueDecoder,
   ) {
     if (data.length < 16) {
-      return [];
+      return (items: [], sqlNulls: []);
     }
 
     final reader = ByteDataReader()..add(data);
@@ -1092,20 +1107,23 @@ class PostgresBinaryDecoder {
 
     reader.read(4); // index
 
+    final sqlNulls = <bool>[];
     bool hasNull = false;
     for (var i = 0; i < size; i++) {
       final len = reader.readInt32();
       if (len == -1) {
         decoded.add(null);
+        sqlNulls.add(true);
         hasNull = true;
       } else {
         final v = valueDecoder(reader, len);
         decoded.add(v);
+        sqlNulls.add(false);
         hasNull = hasNull || (v == null);
       }
     }
 
-    return hasNull ? decoded : decoded.cast<V>();
+    return (items: hasNull ? decoded : decoded.cast<V>(), sqlNulls: sqlNulls);
   }
 
   /// Decode numeric / decimal to String without loosing precision.

lib/src/v3/connection.dart

@@ -1410,15 +1410,14 @@ List<int?>? _mergeTypeOids(
   final length = paramTypes?.length ?? fallbackTypes.length;
   final result = <int?>[];
   for (var i = 0; i < length; i++) {
-    final fromAnnotation =
-        (paramTypes != null && i < paramTypes.length) ? paramTypes[i]?.oid : null;
+    final fromAnnotation = (paramTypes != null && i < paramTypes.length)
+        ? paramTypes[i]?.oid
+        : null;
     if (fromAnnotation != null) {
       result.add(fromAnnotation);
     } else {
       final type = i < fallbackTypes.length ? fallbackTypes[i].type : null;
-      result.add(
-        (type != null && type != Type.unspecified) ? type.oid : null,
-      );
+      result.add((type != null && type != Type.unspecified) ? type.oid : null);
     }
   }
   return result;

test/json_test.dart

@@ -172,4 +172,39 @@ void main() {
       ]);
     });
   });
+
+  withPostgresServer('JSONB array with SQL NULLs', (server) {
+    late Connection connection;
+
+    setUp(() async {
+      connection = await server.newConnection();
+      await connection.execute('CREATE TEMPORARY TABLE t (j jsonb[])');
+    });
+
+    tearDown(() async {
+      await connection.close();
+    });
+
+    test('Can store jsonb[] with SQL NULL elements via TypedValue', () async {
+      final result = await connection.execute(
+        Sql.named('INSERT INTO t (j) VALUES (@a) RETURNING j'),
+        parameters: {
+          'a': TypedValue(Type.jsonbArray, [
+            TypedValue(Type.jsonb, null, isSqlNull: true), // SQL NULL element
+            null, // 'null'::jsonb
+            {'key': 'value'},
+          ]),
+        },
+      );
+      final list = result.single.single as JsonbListView;
+      // Both SQL NULL and JSON null decode to Dart null...
+      expect(list[0], isNull);
+      expect(list[1], isNull);
+      expect(list[2], {'key': 'value'});
+      // ...but isSqlNull distinguishes them.
+      expect(list.isSqlNull(0), isTrue); // SQL NULL
+      expect(list.isSqlNull(1), isFalse); // JSON null ('null'::jsonb)
+      expect(list.isSqlNull(2), isFalse); // real value
+    });
+  });
 }

test/typed_value_parameter_test.dart

@@ -15,37 +15,37 @@ void main() {
       await conn.close();
     });
 
-    test('daterange @> TypedValue(Type.date) without inline annotation',
-        () async {
-      final result = await conn.execute(
-        Sql.named(
-          "SELECT daterange('2026-01-01','2026-01-10','[)') @> @d",
-        ),
-        parameters: {'d': TypedValue(Type.date, DateTime.utc(2026, 1, 5))},
-      );
-      expect(result.single.single, isTrue);
-    });
+    test(
+      'daterange @> TypedValue(Type.date) without inline annotation',
+      () async {
+        final result = await conn.execute(
+          Sql.named("SELECT daterange('2026-01-01','2026-01-10','[)') @> @d"),
+          parameters: {'d': TypedValue(Type.date, DateTime.utc(2026, 1, 5))},
+        );
+        expect(result.single.single, isTrue);
+      },
+    );
 
     test('TypedValue date outside range returns false', () async {
       final result = await conn.execute(
-        Sql.named(
-          "SELECT daterange('2026-01-01','2026-01-10','[)') @> @d",
-        ),
+        Sql.named("SELECT daterange('2026-01-01','2026-01-10','[)') @> @d"),
         parameters: {'d': TypedValue(Type.date, DateTime.utc(2026, 1, 20))},
       );
       expect(result.single.single, isFalse);
     });
 
-    test('integerArray && TypedValue(_int4) without inline annotation',
-        () async {
-      final result = await conn.execute(
-        Sql.named("SELECT ARRAY[1,2,3] && @arr"),
-        parameters: {
-          'arr': TypedValue(Type.integerArray, [2, 5]),
-        },
-      );
-      expect(result.single.single, isTrue);
-    });
+    test(
+      'integerArray && TypedValue(_int4) without inline annotation',
+      () async {
+        final result = await conn.execute(
+          Sql.named('SELECT ARRAY[1,2,3] && @arr'),
+          parameters: {
+            'arr': TypedValue(Type.integerArray, [2, 5]),
+          },
+        );
+        expect(result.single.single, isTrue);
+      },
+    );
 
     test('inline annotation takes precedence over TypedValue type', () async {
       // :date annotation wins even though we pass TypedValue(Type.date, ...)
@@ -79,24 +79,26 @@ void main() {
     // PostgreSQL cannot resolve anyelement polymorphic parameters when the
     // driver sends OID 0 ("unknown") in the Parse message. TypedValue must
     // propagate its type to Parse so the function can be resolved.
-    test('anyelement polymorphic function resolves with TypedValue type',
-        () async {
-      await conn.execute(r'''
+    test(
+      'anyelement polymorphic function resolves with TypedValue type',
+      () async {
+        await conn.execute(r'''
         CREATE OR REPLACE FUNCTION pg_temp.identity(anyelement)
         RETURNS anyelement LANGUAGE sql AS $$ SELECT $1 $$
       ''');
 
-      final intResult = await conn.execute(
-        Sql.named('SELECT pg_temp.identity(@v)'),
-        parameters: {'v': TypedValue(Type.integer, 42)},
-      );
-      expect(intResult.single.single, 42);
+        final intResult = await conn.execute(
+          Sql.named('SELECT pg_temp.identity(@v)'),
+          parameters: {'v': TypedValue(Type.integer, 42)},
+        );
+        expect(intResult.single.single, 42);
 
-      final boolResult = await conn.execute(
-        Sql.named('SELECT pg_temp.identity(@v)'),
-        parameters: {'v': TypedValue(Type.boolean, true)},
-      );
-      expect(boolResult.single.single, isTrue);
-    });
+        final boolResult = await conn.execute(
+          Sql.named('SELECT pg_temp.identity(@v)'),
+          parameters: {'v': TypedValue(Type.boolean, true)},
+        );
+        expect(boolResult.single.single, isTrue);
+      },
+    );
   });
 }