Fix input normalisation of transpile(initial_layout=...) (backport #…

…11031) (#11058)

* 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>
(cherry picked from commit 6148f90)

# Conflicts:
#	test/python/transpiler/test_transpile_layout.py

* Fix backport merge conflicts

The backport of this commit from main failed because the test for this
bug fix was added to an existing file on the main branch but that didn't
exist on the stable/0.25 branch. To fix this the test is moved to a
separate standalone file. Arguably, this should be done on main and
stable/0.45 too as the file the test was added to was for a different
component.

---------

Co-authored-by: Henry Zou <87874865+henryzou50@users.noreply.github.com>
Co-authored-by: Matthew Treinish <mtreinish@kortar.org>

qiskit/compiler/transpiler.py

@@ -503,10 +503,10 @@ 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_set_layout.py

@@ -0,0 +1,34 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2023
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+# pylint: disable=missing-function-docstring
+
+"""Tests the SetLayout pass"""
+
+from qiskit.compiler import transpile
+from qiskit.circuit import QuantumCircuit
+from qiskit.transpiler import CouplingMap
+from qiskit.test import QiskitTestCase
+
+
+class TestSetLayout(QiskitTestCase):
+    """Test the SetLayout pass."""
+
+    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_layout, tqc_2.layout.initial_layout)