Call decompose_once in TaggedOperation (quantumlib#5071)

* Call decompose_once in TaggedOperation * Rename test function * Maybe more robust decomposition
rht · May 1, 2023 · 93df744 · 93df744
1 parent 6c68b17
commit 93df744
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diff --git a/cirq-core/cirq/ops/raw_types.py b/cirq-core/cirq/ops/raw_types.py
@@ -741,7 +741,7 @@ def _json_dict_(self) -> Dict[str, Any]:
         return protocols.obj_to_dict_helper(self, ['sub_operation', 'tags'])
 
     def _decompose_(self) -> 'cirq.OP_TREE':
-        return protocols.decompose(self.sub_operation)
+        return protocols.decompose_once(self.sub_operation, default=None)
 
     def _pauli_expansion_(self) -> value.LinearDict[str]:
         return protocols.pauli_expansion(self.sub_operation)

diff --git a/cirq-core/cirq/protocols/decompose_protocol_test.py b/cirq-core/cirq/protocols/decompose_protocol_test.py
@@ -304,3 +304,19 @@ def x_to_hzh(op: 'cirq.Operation'):
         cirq.measure(a, b, key='m'),
     )
     assert actual == expected
+
+
+def test_decompose_tagged_operation():
+    op = cirq.TaggedOperation(
+        cirq.CircuitOperation(
+            circuit=cirq.FrozenCircuit(
+                [
+                    cirq.Moment(
+                        cirq.SWAP(cirq.LineQubit(0), cirq.LineQubit(1)),
+                    ),
+                ]
+            ),
+        ),
+        'tag',
+    )
+    assert cirq.decompose_once(op) == cirq.decompose_once(op.untagged)