fix: use SplayTreeSet to resolve inconsistent hashCodes (#142)

felangel · Aug 19, 2022 · eb18291 · eb18291
1 parent dfffe62
commit eb18291
Show file tree

Hide file tree

Showing 2 changed files with 18 additions and 0 deletions.
diff --git a/lib/src/equatable_utils.dart b/lib/src/equatable_utils.dart
@@ -1,3 +1,5 @@
+import 'dart:collection';
+
 import 'package:collection/collection.dart';
 import 'package:equatable/equatable.dart';
 
@@ -46,6 +48,11 @@ int _combine(int hash, dynamic object) {
     });
     return hash;
   }
+  if (object is Set && object is! SplayTreeSet) {
+    // this is needed to have a consistent iteration order so that the produced
+    // hash is consistent independently of the Set insertion order
+    object = SplayTreeSet<dynamic>.from(object);
+  }
   if (object is Iterable) {
     for (final value in object) {
       hash = hash ^ _combine(hash, value);

diff --git a/test/equatable_test.dart b/test/equatable_test.dart
@@ -968,6 +968,17 @@ void main() {
         expect(instanceA.hashCode == instanceB.hashCode, true);
       });
 
+      test('should return when Set values are same but in different order', () {
+        final instanceA = SimpleEquatable<Set<String>>(
+          Set.from(<String>['A', 'B']),
+        );
+        final instanceB = SimpleEquatable<Set<String>>(
+          Set.from(<String>['B', 'A']),
+        );
+        expect(instanceA == instanceB, true);
+        expect(instanceA.hashCode == instanceB.hashCode, true);
+      });
+
       test('should return when values are different', () {
         final instanceA = SimpleEquatable<Set<String>>(
           Set.from(<String>['A', 'B']),