Revert Session.from_id 0.15.0 changes

qiskit_ibm_runtime/session.py

@@ -23,9 +23,8 @@
 from .runtime_program import ParameterNamespace
 from .program.result_decoder import ResultDecoder
 from .ibm_backend import IBMBackend
-from .exceptions import IBMInputValueError
-from .utils.deprecation import deprecate_arguments
 from .utils.default_session import set_cm_session
+from .utils.deprecation import deprecate_arguments
 
 
 def _active_session(func):  # type: ignore
@@ -284,44 +283,28 @@ def service(self) -> QiskitRuntimeService:
     def from_id(
         cls,
         session_id: str,
-        service: QiskitRuntimeService,
+        service: Optional[QiskitRuntimeService] = None,
         backend: Optional[Union[str, IBMBackend]] = None,
     ) -> "Session":
         """Construct a Session object with a given session_id
 
         Args:
-            session_id: the id of the session to be created. This must be an already
+            session_id: the id of the session to be created. This can be an already
                 existing session id.
             service: instance of the ``QiskitRuntimeService`` class.
             backend: instance of :class:`qiskit_ibm_runtime.IBMBackend` class or
                 string name of backend.
 
-        Raises:
-            IBMInputValueError: If given `session_id` does not exist. or the backend passed in does
-                not match the original session backend.
-
         Returns:
             A new Session with the given ``session_id``
-        """
 
+        """
         if backend:
             deprecate_arguments("backend", "0.15.0", "Sessions do not support multiple backends.")
-            if isinstance(backend, IBMBackend):
-                backend = backend.name
-
-        response = service._api_client.session_details(session_id)
-        if response:
-            session_backend = response.get("backend_name")
-            if backend and backend != session_backend:
-                raise IBMInputValueError(
-                    f"The session_id {session_id} was created with backend {session_backend}, "
-                    f"but backend {backend} was given."
-                )
-            session = cls(service, session_backend)
-            session._session_id = session_id
-            return session
 
-        raise IBMInputValueError(f"The session_id {session_id} does not exist.")
+        session = cls(service, backend)
+        session._session_id = session_id
+        return session
 
     def __enter__(self) -> "Session":
         set_cm_session(self)

releasenotes/notes/revert-from-id-9b87ea2d948251d6.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Reverting `0.15.0` changes to :meth:`~qiskit_ibm_runtime.Session.from_id` because it was
+    a breaking change without proper deprecation. 
+

test/integration/test_session.py

@@ -21,7 +21,6 @@
 from qiskit.result import Result
 
 from qiskit_ibm_runtime import Estimator, Session, Sampler, Options
-from qiskit_ibm_runtime.exceptions import IBMInputValueError
 
 from ..decorators import run_integration_test, quantum_only
 from ..ibm_test_case import IBMIntegrationTestCase
@@ -91,16 +90,16 @@ def test_using_correct_instance(self, service):
 
     @run_integration_test
     def test_session_from_id(self, service):
-        """Test creating a session with from_id with simulator."""
+        """Test creating a session from a given id"""
         backend = service.backend("ibmq_qasm_simulator")
-        session = Session(service=service, backend=backend)
-
-        sampler = Sampler(session=session)
+        with Session(service, backend=backend) as session:
+            sampler = Sampler(session=session)
+            job = sampler.run(ReferenceCircuits.bell(), shots=400)
+            session_id = job.session_id
+        new_session = Session.from_id(backend=backend, session_id=session_id)
+        sampler = Sampler(session=new_session)
         job = sampler.run(ReferenceCircuits.bell(), shots=400)
-        session_id = job.session_id
-
-        with self.assertRaises(IBMInputValueError):
-            _ = Session.from_id(session_id=session_id, service=service)
+        self.assertEqual(session_id, job.session_id)
 
 
 class TestBackendRunInSession(IBMIntegrationTestCase):