Fix issue with deepcopy and scope API.

qiskit/circuit/quantumcircuit.py

@@ -562,9 +562,11 @@ def __deepcopy__(self, memo=None):
         #   copy.deepcopy(memo).
         cls = self.__class__
         result = cls.__new__(cls)
-        for k in self.__dict__.keys() - {"_data"}:
+        for k in self.__dict__.keys() - {"_data", "_builder_api"}:
             setattr(result, k, copy.deepcopy(self.__dict__[k], memo))
 
+        result._builder_api = _OuterCircuitScopeInterface(result)
+
         # Avoids pulling self._data into a Python list
         # like we would when pickling.
         result._data = self._data.copy()

test/python/circuit/test_circuit_operations.py

@@ -12,6 +12,7 @@
 
 
 """Test Qiskit's QuantumCircuit class."""
+import copy
 
 import numpy as np
 from ddt import data, ddt
@@ -638,6 +639,20 @@ def test_measure_all(self):
 
         self.assertEqual(expected, circuit)
 
+    def test_measure_all_after_deepcopy(self):
+        """
+        Test measure_all on a circuit that has been deep-copied.
+        """
+        qc = QuantumCircuit(2)
+        qc.h(1)
+
+        qc2 = copy.deepcopy(qc)
+
+        qc.measure_all()
+        qc2.measure_all()
+
+        self.assertEqual(qc, qc2)
+
     def test_measure_all_not_add_bits_equal(self):
         """Test measure_all applies measurements to all qubits.
         Does not create a new ClassicalRegister if the existing one is big enough.