fix: do not allow to pass A&B custom options to backend.run()

qiskit_alice_bob_provider/local/backend.py

@@ -23,6 +23,7 @@
 from qiskit_aer.backends.aerbackend import AerBackend
 
 from ..processor.description import ProcessorDescription
+from ..processor.utils import get_init_params
 from .job import ProcessorSimulationJob
 from .quantum_errors import build_quantum_error_passes
 from .readout_errors import build_readout_noise_model
@@ -73,12 +74,13 @@ def __init__(
 
         Args:
             processor (ProcessorDescription): the description of the quantum
-            processor to simulate
+                processor to simulate
             execution_backend (AerBackend, optional): the Qiskit simulator used
-            in the background for simulation. Defaults to AerSimulator().
+                in the background for simulation. Defaults to AerSimulator().
             name (Optional[str], optional): an optional name for the backend.
         """
         super().__init__(name=name, backend_version=1)
+        self._processor = processor
         self._target = processor_to_target(processor)
         self._execution_backend = execution_backend
         self._execution_backend.set_option('n_qubits', self._target.num_qubits)
@@ -141,11 +143,31 @@ def run(
 
         Args:
             run_input (Union[QuantumCircuit, List[QuantumCircuit]]): one or
-            multiple circuits to simulate.
+                multiple circuits to simulate.
             **options: additional arguments are interpreted as options for
-            the underlying execution backend, usually an instance of
-            AerSimulator.
+                the underlying execution backend, usually an instance of
+                AerSimulator.
+
+        Returns:
+            ProcessorSimulationJob: A wrapper of a submitted asynchronous
+                AerJob
+
+        Raises:
+            ValueError: if a custom A&B option is passed to backend.run()
         """
+        if options:
+            # Check that the options passed are not custom A&B options of the
+            # processor because they will be ignored in this function.
+            processor_params = get_init_params(self._processor.__class__)
+            for option in options:
+                if option not in processor_params:
+                    continue
+                raise ValueError(
+                    f'The Alice & Bob custom option {option} is not allowed '
+                    'for backend.run() with local provider. '
+                    'You should pass it to get_backend() instead.'
+                )
+
         if isinstance(run_input, QuantumCircuit):
             circuits = [run_input]
         else:

qiskit_alice_bob_provider/processor/utils.py

@@ -14,10 +14,12 @@
 #    limitations under the License.
 ##############################################################################
 
+from inspect import signature
 from itertools import product
 from typing import Dict, List, Union
 
 import numpy as np
+from typing_extensions import Type
 
 
 def pauli_errors_to_chi(pauli_errors: Dict[str, float]) -> np.ndarray:
@@ -220,3 +222,9 @@ def tensor_errors(
     for (a_pauli, a_prob), (b_pauli, b_prob) in product(a.items(), b.items()):
         output[b_pauli + a_pauli] = a_prob * b_prob
     return output
+
+
+def get_init_params(cls: Type) -> List[str]:
+    """Get the names of the parameters of a class's __init__ method"""
+    init_signature = signature(cls.__init__)
+    return list(init_signature.parameters.keys())[1:]  # Skip 'self'

tests/local/test_backend.py

@@ -1,10 +1,12 @@
 from typing import List
 
 import numpy as np
+import pytest
 from qiskit import QuantumCircuit, transpile
 from qiskit.circuit.library import Initialize
 
 from qiskit_alice_bob_provider.local.backend import ProcessorSimulator
+from qiskit_alice_bob_provider.processor.logical_cat import LogicalCatProcessor
 from qiskit_alice_bob_provider.processor.physical_cat import (
     PhysicalCatProcessor,
 )
@@ -43,6 +45,26 @@ def test_set_execution_backend_options() -> None:
     assert sum(backend.run(transpiled).result().get_counts().values()) == 7
 
 
+def test_run_override_nbar_error() -> None:
+    """
+    Test that passing average_nb_photons option to backend.run() is not allowed
+    """
+    circ = QuantumCircuit(1, 1)
+    backend = ProcessorSimulator(PhysicalCatProcessor())
+    transpiled = transpile(circ, backend)
+    with pytest.raises(ValueError):
+        _ = backend.run(transpiled, shots=100, average_nb_photons=4)
+    with pytest.raises(ValueError):
+        _ = backend.run(transpiled, shots=100, kappa_1=4)
+
+    backend = ProcessorSimulator(LogicalCatProcessor())
+    transpiled = transpile(circ, backend)
+    with pytest.raises(ValueError):
+        _ = backend.run(transpiled, shots=100, average_nb_photons=4)
+    with pytest.raises(ValueError):
+        _ = backend.run(transpiled, shots=100, kappa_1=4)
+
+
 def test_translation_plugin() -> None:
     backend = ProcessorSimulator(SimpleProcessor(1))