Implement equality comparisons on System.Array

Author: BCSharp

Src/IronPython/Runtime/Operations/ArrayOps.cs

@@ -87,6 +87,34 @@ public static object __new__(CodeContext context, PythonType pythonType, object
             return res;
         }
 
+        [StaticExtensionMethod]
+        public static object __eq__(CodeContext context, Array self, [NotNone] Array other) {
+            if (self is null) throw PythonOps.TypeError("expected Array, got None");
+            if (other is null) throw PythonOps.TypeError("expected Array, got None");
+
+            if (self.GetType() != other.GetType()) return ScriptingRuntimeHelpers.False;
+            if (self.Length != other.Length) return ScriptingRuntimeHelpers.False;
+            for (int i = 0; i < self.Rank; i++) {
+                if (self.GetLowerBound(i) != other.GetLowerBound(i)) return ScriptingRuntimeHelpers.False;
+            }
+
+            return ScriptingRuntimeHelpers.BooleanToObject(
+                ((IStructuralEquatable)self).Equals(other, context.LanguageContext.EqualityComparerNonGeneric)
+            );
+        }
+
+        [StaticExtensionMethod]
+        [return: MaybeNotImplemented]
+        public static object __eq__(CodeContext context, object self, object? other) => NotImplementedType.Value;
+
+        [StaticExtensionMethod]
+        public static object __ne__(CodeContext context, Array self, [NotNone] Array other)
+            => ScriptingRuntimeHelpers.BooleanToObject(ReferenceEquals(__eq__(context, self, other), ScriptingRuntimeHelpers.False));
+
+        [StaticExtensionMethod]
+        [return: MaybeNotImplemented]
+        public static object __ne__(CodeContext context, object self, object? other) => NotImplementedType.Value;
+
         /// <summary>
         /// Multiply two object[] arrays - slow version, we need to get the type, etc...
         /// </summary>

Tests/test_array.py

@@ -279,4 +279,43 @@ def test_tuple_indexer(self):
         array1[0,0] = 5
         self.assertEqual(array1[0,0], array1[(0,0)])
 
+    def test_equality(self):
+        a = System.Array.CreateInstance(int, 5)
+        a2 = System.Array.CreateInstance(int, 5) # same as a
+        b = System.Array.CreateInstance(int, 5, 6) # different rank
+        c = System.Array.CreateInstance(int, 6) # different length
+        d = System.Array.CreateInstance(int, (5,), (1,)) # different base
+        e = System.Array.CreateInstance(System.Int32, 5) # different element type
+        l = [0] * 5 # different type
+
+        self.assertTrue(a == a2)
+        self.assertTrue(a2 == a)
+        self.assertFalse(a != a2)
+        self.assertFalse(a2 != a)
+
+        self.assertFalse(a == b)
+        self.assertFalse(b == a)
+        self.assertTrue(a != b)
+        self.assertTrue(b != a)
+
+        self.assertFalse(a == c)
+        self.assertFalse(c == a)
+        self.assertTrue(a != c)
+        self.assertTrue(c != a)
+
+        self.assertFalse(a == d)
+        self.assertFalse(d == a)
+        self.assertTrue(a != d)
+        self.assertTrue(d != a)
+
+        self.assertFalse(a == e)
+        self.assertFalse(e == a)
+        self.assertTrue(a != e)
+        self.assertTrue(e != a)
+
+        self.assertFalse(a == l)
+        self.assertFalse(l == a)
+        self.assertTrue(a != l)
+        self.assertTrue(l != a)
+
 run_test(__name__)