Deprecate provider-specific fake backends,FakeProvider class and related tools in 0.46

qiskit/providers/fake_provider/fake_backend.py

@@ -1,6 +1,6 @@
 # This code is part of Qiskit.
 #
-# (C) Copyright IBM 2019, 2023.
+# (C) Copyright IBM 2019, 2024.
 #
 # 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
@@ -33,6 +33,7 @@
 from qiskit.providers import basic_provider
 from qiskit.transpiler import Target
 from qiskit.providers.backend_compat import convert_to_target
+from qiskit.utils.deprecation import deprecate_func
 
 from .utils.json_decoder import (
     decode_backend_configuration,
@@ -56,7 +57,7 @@ class FakeBackendV2(BackendV2):
 
     The class inherits :class:`~qiskit.providers.BackendV2` class. This version
     differs from earlier :class:`~qiskit.providers.fake_provider.FakeBackend` (V1) class in a
-    few aspects. Firstly, configuration attribute no longer exsists. Instead,
+    few aspects. Firstly, configuration attribute no longer exists. Instead,
     attributes exposing equivalent required immutable properties of the backend
     device are added. For example ``fake_backend.configuration().n_qubits`` is
     accessible from ``fake_backend.num_qubits`` now. Secondly, this version
@@ -71,6 +72,15 @@ class FakeBackendV2(BackendV2):
     defs_filename = None
     backend_name = None
 
+    @deprecate_func(
+        additional_msg="This class has been migrated to the `qiskit_ibm_runtime` package. "
+        "To migrate your code, run `pip install qiskit-ibm-runtime` and use "
+        "`from qiskit_ibm_runtime.fake_provider import FakeExample` "
+        "instead of `from qiskit.providers.fake_provider import FakeExample`. ",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self):
         """FakeBackendV2 initializer."""
         self._conf_dict = self._get_conf_dict_from_json()

qiskit/providers/fake_provider/fake_backend_v2.py

@@ -32,11 +32,19 @@
 from qiskit.providers.options import Options
 from qiskit.transpiler import Target, InstructionProperties
 from qiskit.providers.basic_provider.basic_simulator import BasicSimulator
+from qiskit.utils.deprecation import deprecate_func
 
 
 class FakeBackendV2(BackendV2):
     """A mock backend that doesn't implement run() to test compatibility with Terra internals."""
 
+    @deprecate_func(
+        additional_msg="Use the `qiskit.providers.basic_provider.GenericBackendV2` "
+        "class instead.",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self):
         super().__init__(
             None,
@@ -111,6 +119,13 @@ def qubit_properties(self, qubit):
 class FakeBackend5QV2(BackendV2):
     """A mock backend that doesn't implement run() to test compatibility with Terra internals."""
 
+    @deprecate_func(
+        additional_msg="Use the `qiskit.providers.basic_provider.GenericBackendV2` "
+        "class instead.",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self, bidirectional=True):
         super().__init__(
             None,
@@ -183,6 +198,13 @@ def run(self, run_input, **options):
 class FakeBackendSimple(BackendV2):
     """A fake simple backend that wraps BasicSimulator to implement run()."""
 
+    @deprecate_func(
+        additional_msg="Use the `qiskit.providers.basic_provider.GenericBackendV2` "
+        "class instead.",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self):
         super().__init__(
             None,

qiskit/providers/fake_provider/fake_job.py

@@ -1,6 +1,6 @@
 # This code is part of Qiskit.
 #
-# (C) Copyright IBM 2019.
+# (C) Copyright IBM 2019, 2024.
 #
 # 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
@@ -19,13 +19,20 @@
 
 from qiskit.providers import JobV1
 from qiskit.providers.jobstatus import JobStatus
+from qiskit.utils.deprecation import deprecate_func
 
 
 class FakeJob(JobV1):
     """Fake simulator job"""
 
     _executor = futures.ThreadPoolExecutor()
 
+    @deprecate_func(
+        additional_msg="Use the `qiskit.providers.JobV1` class directly instead.",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self, backend, job_id, fn):
         super().__init__(backend, job_id)
         self._backend = backend

qiskit/providers/fake_provider/fake_mumbai_v2.py

@@ -30,11 +30,19 @@
 from qiskit.providers.backend import BackendV2, QubitProperties
 from qiskit.providers.options import Options
 from qiskit.transpiler import Target, InstructionProperties
+from qiskit.utils.deprecation import deprecate_func
 
 
 class FakeMumbaiFractionalCX(BackendV2):
     """A fake mumbai backend."""
 
+    @deprecate_func(
+        additional_msg="Use the `qiskit.providers.basic_provider.GenericBackendV2` "
+        "class instead.",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self):
         super().__init__(
             name="FakeMumbaiFractionalCX",

qiskit/providers/fake_provider/fake_provider.py

@@ -1,6 +1,6 @@
 # This code is part of Qiskit.
 #
-# (C) Copyright IBM 2019.
+# (C) Copyright IBM 2019, 2024.
 #
 # 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
@@ -18,6 +18,7 @@
 
 from qiskit.providers.provider import ProviderV1
 from qiskit.providers.exceptions import QiskitBackendNotFoundError
+from qiskit.utils.deprecation import deprecate_func
 
 from .backends import *
 from .fake_qasm_simulator import FakeQasmSimulator
@@ -28,6 +29,15 @@
 class FakeProviderFactory:
     """Fake provider factory class."""
 
+    @deprecate_func(
+        additional_msg="This class has been migrated to the `qiskit_ibm_runtime` package. "
+        "To migrate your code, run `pip install qiskit-ibm-runtime` and "
+        "use `from qiskit_ibm_runtime.fake_provider import FakeProviderExample` "
+        "instead of `from qiskit.providers.fake_provider import FakeProviderExample`.",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self):
         self.fake_provider = FakeProvider()
 
@@ -86,6 +96,15 @@ def get_backend(self, name=None, **kwargs):
     def backends(self, name=None, **kwargs):
         return self._backends
 
+    @deprecate_func(
+        additional_msg="This class has been migrated to the `qiskit_ibm_runtime` package. "
+        "To migrate your code, run `pip install qiskit-ibm-runtime` and "
+        "use `from qiskit_ibm_runtime.fake_provider import FakeProviderExample` "
+        "instead of `from qiskit.providers.fake_provider import FakeProviderExample`.",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self):
         self._backends = [
             FakeAlmadenV2(),
@@ -160,6 +179,15 @@ def get_backend(self, name=None, **kwargs):
     def backends(self, name=None, **kwargs):
         return self._backends
 
+    @deprecate_func(
+        additional_msg="This class has been migrated to the `qiskit_ibm_runtime` package. "
+        "To migrate your code, run `pip install qiskit-ibm-runtime` and "
+        "use `from qiskit_ibm_runtime.fake_provider import FakeProviderExample` "
+        "instead of `from qiskit.providers.fake_provider import FakeProviderExample`.",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self):
         self._backends = [
             FakeAlmaden(),

qiskit/providers/fake_provider/fake_pulse_backend.py

@@ -1,6 +1,6 @@
 # This code is part of Qiskit.
 #
-# (C) Copyright IBM 2020.
+# (C) Copyright IBM 2020, 2024.
 #
 # 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
@@ -14,6 +14,8 @@
 Fake backend abstract class for mock backends supporting OpenPulse.
 """
 
+import warnings
+
 from qiskit.exceptions import QiskitError
 from qiskit.providers.models import PulseBackendConfiguration, PulseDefaults
 
@@ -26,6 +28,22 @@ class FakePulseBackend(FakeQasmBackend):
 
     defs_filename = None
 
+    def __init__(self):
+        super().__init__()
+        # This is a deprecation warning for the subclasses.
+        # FakePulseBackend is not deprecated.
+        warnings.warn(
+            message="All fake backend instances based on real device snapshots (`FakeVigo`,"
+            "`FakeSherbrooke`,...) have been migrated to the `qiskit_ibm_runtime` package. "
+            "These classes are deprecated as of qiskit 0.46.0 and will be removed in qiskit 1.0.0. "
+            "To migrate your code, run `pip install qiskit-ibm-runtime` and use "
+            "`from qiskit_ibm_runtime.fake_provider import FakeExample` "
+            "instead of `from qiskit.providers.fake_provider import FakeExample`. "
+            "If you are using a custom fake backend implementation, you don't need to take any action.",
+            category=DeprecationWarning,
+            stacklevel=2,
+        )
+
     def defaults(self):
         """Returns a snapshot of device defaults"""
         if not self._defaults:

qiskit/providers/fake_provider/fake_qasm_backend.py

@@ -1,6 +1,6 @@
 # This code is part of Qiskit.
 #
-# (C) Copyright IBM 2020.
+# (C) Copyright IBM 2020, 2024.
 #
 # 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
@@ -16,6 +16,7 @@
 
 import json
 import os
+import warnings
 
 from qiskit.exceptions import QiskitError
 from qiskit.providers.models import BackendProperties, QasmBackendConfiguration
@@ -40,6 +41,19 @@ def __init__(self):
         self._defaults = None
         self._properties = None
         super().__init__(configuration)
+        # This is a deprecation warning for the subclasses.
+        # FakeQasmBackend is not deprecated.
+        warnings.warn(
+            message="All fake backend instances based on real device snapshots (`FakeVigo`,"
+            "`FakeSherbrooke`,...) have been migrated to the `qiskit_ibm_runtime` package. "
+            "These classes are deprecated as of qiskit 0.46.0 and will be removed in qiskit 1.0.0. "
+            "To migrate your code, run `pip install qiskit-ibm-runtime` and use "
+            "`from qiskit_ibm_runtime.fake_provider import FakeExample` "
+            "instead of `from qiskit.providers.fake_provider import FakeExample`. "
+            "If you are using a custom fake backend implementation, you don't need to take any action.",
+            category=DeprecationWarning,
+            stacklevel=2,
+        )
 
     def properties(self):
         """Returns a snapshot of device properties"""

qiskit/providers/fake_provider/fake_qasm_simulator.py

@@ -15,13 +15,20 @@
 """
 
 from qiskit.providers.models import GateConfig, QasmBackendConfiguration
+from qiskit.utils.deprecation import deprecate_func
 
 from .fake_backend import FakeBackend
 
 
 class FakeQasmSimulator(FakeBackend):
     """A fake simulator backend."""
 
+    @deprecate_func(
+        additional_msg="Use the `qiskit.providers.basic_provider.BasicSimulator` class instead.",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self):
         configuration = QasmBackendConfiguration(
             backend_name="fake_qasm_simulator",

qiskit/providers/fake_provider/fake_qobj.py

@@ -1,6 +1,6 @@
 # This code is part of Qiskit.
 #
-# (C) Copyright IBM 2019.
+# (C) Copyright IBM 2019, 2024.
 #
 # 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
@@ -23,13 +23,20 @@
     QasmQobjExperiment,
     QasmQobjConfig,
 )
+from qiskit.utils.deprecation import deprecate_func
 
 from .fake_qasm_simulator import FakeQasmSimulator
 
 
 class FakeQobj(QasmQobj):
     """A fake `Qobj` instance."""
 
+    @deprecate_func(
+        additional_msg="Use the `qiskit.qobj.QasmQobj` class directly instead.",
+        since="0.46.0",
+        removal_timeline="Qiskit 1.0",
+        package_name="qiskit",
+    )
     def __init__(self):
         qobj_id = "test_id"
         config = QasmQobjConfig(shots=1024, memory_slots=1)

qiskit/test/base.py

@@ -245,7 +245,6 @@ def setUpClass(cls):
         ]
         for msg in allow_DeprecationWarning_message:
             warnings.filterwarnings("default", category=DeprecationWarning, message=msg)
-
         allow_aer_DeprecationWarning_message = [
             # This warning should be fixed once Qiskit/qiskit-aer#1761 is in a release version of Aer.
             "Setting metadata to None.*",
@@ -257,11 +256,15 @@ def setUpClass(cls):
             "The qiskit.extensions module is deprecated since Qiskit 0.46.0. It will be removed "
             "in the Qiskit 1.0 release.",
         ]
-
         for msg in allow_aer_DeprecationWarning_message:
             warnings.filterwarnings(
                 "default", category=DeprecationWarning, module="qiskit_aer.*", message=msg
             )
+        # Ignore fake backend deprecation warnings to avoid over-crowding the test log
+        ignore_fake_backend_message = r".*been migrated to the `qiskit_ibm_runtime` package.*"
+        warnings.filterwarnings(
+            "ignore", category=DeprecationWarning, message=ignore_fake_backend_message
+        )
 
 
 class FullQiskitTestCase(QiskitTestCase):