Fixed handling of a list of coupling_maps passed to transpile() (Qisk…

…it#9886)

* Fixed handling of a list of coupling_maps passed to transpile()

Closes Qiskit#9885

* Update qiskit/compiler/transpiler.py

* Add test

* Release note

* Fix test

qiskit/compiler/transpiler.py

@@ -355,8 +355,8 @@ def callback_func(**kwargs):
         ignore_backend_supplied_default_methods,
     )
     # Get transpile_args to configure the circuit transpilation job(s)
-    if coupling_map in unique_transpile_args:
-        cmap_conf = unique_transpile_args["coupling_map"]
+    if "coupling_map" not in shared_args:
+        cmap_conf = [a["pass_manager_config"]["coupling_map"] for a in unique_transpile_args]
     else:
         cmap_conf = [shared_args["coupling_map"]] * len(circuits)
     _check_circuits_coupling_map(circuits, cmap_conf, backend)

releasenotes/notes/transpile-coupling-maps-3a137f4ca8e97745.yaml

@@ -0,0 +1,8 @@
+---
+fixes:
+  - |
+    An issue that prevented :func:`~qiskit.transpile` from working when passed
+    a list of :class:`~qiskit.transpiler.CouplingMap` objects was fixed. Note
+    that passing such a list of coupling maps is deprecated and will not be
+    possible starting with Qiskit Terra 0.25. Fixes
+    `#9885 <https://github.com/Qiskit/qiskit-terra/issues/9885>`_.

test/python/compiler/test_transpiler.py

@@ -1980,6 +1980,36 @@ def test_backendv2_and_coupling_map(self, opt_level):
                 qubit_1 = tqc.find_bit(inst.qubits[1]).index
                 self.assertEqual(qubit_1, qubit_0 + 1)
 
+    def test_transpile_with_multiple_coupling_maps(self):
+        """Test passing a different coupling map for every circuit"""
+        backend = FakeNairobiV2()
+
+        qc = QuantumCircuit(3)
+        qc.cx(0, 2)
+
+        # Add a connection between 0 and 2 so that transpile does not change
+        # the gates
+        cmap = CouplingMap.from_line(7)
+        cmap.add_edge(0, 2)
+
+        with self.assertWarnsRegex(
+            DeprecationWarning, "Passing in a list of arguments for coupling_map is deprecated"
+        ):
+            # Initial layout needed to prevent transpiler from relabeling
+            # qubits to avoid doing the swap
+            tqc = transpile(
+                [qc] * 2,
+                backend,
+                coupling_map=[backend.coupling_map, cmap],
+                initial_layout=(0, 1, 2),
+            )
+
+        # Check that the two coupling maps were used. The default should
+        # require swapping (extra cx's) and the second one should not (just the
+        # original cx).
+        self.assertEqual(tqc[0].count_ops()["cx"], 4)
+        self.assertEqual(tqc[1].count_ops()["cx"], 1)
+
     @data(0, 1, 2, 3)
     def test_backend_and_custom_gate(self, opt_level):
         """Test transpile() with BackendV2, custom basis pulse gate."""