Fix the text drawer with partially idle wires

qiskit/dagcircuit/dagcircuit.py

@@ -2090,7 +2090,7 @@ def layers(self, *, vars_mode: _VarsMode = "captures"):
             new_layer = self.copy_empty_like(vars_mode=vars_mode)
 
             for node in op_nodes:
-                new_layer._apply_op_node_back(node, check=False)
+                new_layer._apply_op_node_back(copy.copy(node), check=False)
 
             # The quantum registers that have an operation in this layer.
             support_list = [

releasenotes/notes/fix-textdrawer-idle-layer-91e6c3c6d7656e98.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixed a bug in the circuit text drawer, which could fail if the circuit
+    had an initial layer with idle wires.
+    Fixed `#13128 <https://github.com/Qiskit/qiskit/issues/13128>`__.

test/python/visualization/test_circuit_text_drawer.py

@@ -4092,6 +4092,30 @@ def test_does_not_mutate_circuit(self):
         circuit.draw(idle_wires=False)
         self.assertEqual(circuit.num_qubits, before_qubits)
 
+    def test_wires_only_initially_idle(self):
+        """Test a circuit where wires are only idle in the first layer.
+
+        Regression test for https://github.com/Qiskit/qiskit/issues/13128
+        """
+        expected = "\n".join(
+            [
+                "     ┌───┐ ░ ┌───┐",
+                "q_0: ┤ X ├─░─┤ H ├",
+                "     └───┘ ░ ├───┤",
+                "q_1: ──────░─┤ H ├",
+                "           ░ └───┘",
+            ]
+        )
+        qc = QuantumCircuit(2)
+        qc.x(0)
+        qc.barrier([0, 1])
+        qc.h(range(2))
+
+        self.assertEqual(
+            str(circuit_drawer(qc, output="text", idle_wires=False)),
+            expected,
+        )
+
 
 class TestTextNonRational(QiskitTestCase):
     """non-rational numbers are correctly represented"""