Issue #25718: Fixed copying object with state with boolean value is false.

Lib/copy.py

@@ -279,7 +279,7 @@ def _reconstruct(x, info, deep, memo=None):
     if n > 2:
         state = info[2]
     else:
-        state = {}
+        state = None
     if n > 3:
         listiter = info[3]
     else:
@@ -293,7 +293,7 @@ def _reconstruct(x, info, deep, memo=None):
     y = callable(*args)
     memo[id(x)] = y
 
-    if state:
+    if state is not None:
         if deep:
             state = deepcopy(state, memo)
         if hasattr(y, '__setstate__'):

Lib/test/test_copy.py

@@ -213,6 +213,9 @@ class TestCopy(unittest.TestCase):
                 return self.foo == other.foo
         x = C(42)
         self.assertEqual(copy.copy(x), x)
+        # State with boolean value is false (issue #25718)
+        x = C(0.0)
+        self.assertEqual(copy.copy(x), x)
 
     # The deepcopy() method
 
@@ -517,6 +520,12 @@ class TestCopy(unittest.TestCase):
         self.assertEqual(y, x)
         self.assertIsNot(y, x)
         self.assertIsNot(y.foo, x.foo)
+        # State with boolean value is false (issue #25718)
+        x = C([])
+        y = copy.deepcopy(x)
+        self.assertEqual(y, x)
+        self.assertIsNot(y, x)
+        self.assertIsNot(y.foo, x.foo)
 
     def test_deepcopy_reflexive_inst(self):
         class C:

Misc/NEWS

@@ -20,6 +20,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #25718: Fixed copying object with state with boolean value is false.
+
 - Issue #10131: Fixed deep copying of minidom documents.  Based on patch
   by Marian Ganisin.