Fix input normalisation of transpile(initial_layout=...) (#11031)

* Fixed issue10554 by modifying _parse_initial_layout in transpile to normalize input of range to a list

* Added test and bugfix note

* Handle consumable iterables

* Fix release-note cross references

---------

Co-authored-by: Jake Lishman <jake.lishman@ibm.com>

qiskit/compiler/transpiler.py

@@ -512,10 +512,10 @@ def _parse_initial_layout(initial_layout):
         return initial_layout
     if isinstance(initial_layout, dict):
         return Layout(initial_layout)
+    initial_layout = list(initial_layout)
     if all(phys is None or isinstance(phys, Qubit) for phys in initial_layout):
         return Layout.from_qubit_list(initial_layout)
-    else:
-        return initial_layout
+    return initial_layout
 
 
 def _parse_instruction_durations(backend, inst_durations, dt, circuit):

releasenotes/notes/fix-input-normalization-of-transpile-initial-layout.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixed a regression in :func:`.transpile`, where an ``initial_layout`` given
+    as a :class:`range` object would no longer be treated as a valid input.
+    Fixed `#10544 <https://github.com/Qiskit/qiskit/issues/10554>`__.

test/python/transpiler/test_transpile_layout.py

@@ -294,3 +294,13 @@ def test_initial_virtual_layout_filter_ancillas(self):
                 }
             ),
         )
+
+    def test_initial_layout_consistency_for_range_and_list(self):
+        qc = QuantumCircuit(3)
+        qc.h(0)
+        qc.cx(0, 1)
+        qc.cx(0, 2)
+        cmap = CouplingMap.from_line(3, bidirectional=False)
+        tqc_1 = transpile(qc, coupling_map=cmap, initial_layout=range(3), seed_transpiler=42)
+        tqc_2 = transpile(qc, coupling_map=cmap, initial_layout=list(range(3)), seed_transpiler=42)
+        self.assertEqual(tqc_1.layout.initial_index_layout(), tqc_2.layout.initial_index_layout())