Fix calling backend.name() for backendV2 (#11065) (#11076)

* add check for backend version to get backend name * move backend_interface_version * check backend is None before get version * Update qiskit/utils/backend_utils.py Co-authored-by: Matthew Treinish <[email protected]> * Update releasenotes/notes/fix_backend_name-e84661707058b529.yaml Co-authored-by: Matthew Treinish <[email protected]> --------- Co-authored-by: Matthew Treinish <[email protected]> (cherry picked from commit d781dcc) Co-authored-by: Jun Doi <[email protected]>
Qiskit · Oct 21, 2023 · 2f76ef0 · 2f76ef0
1 parent 4b0d30e
commit 2f76ef0
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diff --git a/qiskit/utils/backend_utils.py b/qiskit/utils/backend_utils.py
@@ -181,16 +181,21 @@ def is_statevector_backend(backend):
     Returns:
         bool: True is statevector
     """
+    if backend is None:
+        return False
+    backend_interface_version = _get_backend_interface_version(backend)
     if has_aer():
         from qiskit.providers.aer.backends import AerSimulator, StatevectorSimulator
 
         if isinstance(backend, StatevectorSimulator):
             return True
-        if isinstance(backend, AerSimulator) and "aer_simulator_statevector" in backend.name():
-            return True
-    if backend is None:
-        return False
-    backend_interface_version = _get_backend_interface_version(backend)
+        if isinstance(backend, AerSimulator):
+            if backend_interface_version <= 1:
+                name = backend.name()
+            else:
+                name = backend.name
+            if "aer_simulator_statevector" in name:
+                return True
     if backend_interface_version <= 1:
         return backend.name().startswith("statevector")
     else:

diff --git a/releasenotes/notes/fix_backend_name-e84661707058b529.yaml b/releasenotes/notes/fix_backend_name-e84661707058b529.yaml
@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Fixed an issue in the :class:`.QuantumInstance` class where it was assuming
+    all ``AerSimulator`` backends were always :class:`.BackendV1`. This would cause
+    combatibility issues with the 0.13.0 release of ``qiskit-aer`` which is starting to
+    use :class:`.BackendV2` for `AerSimulator`` backends.