Add warning if primitive initalized outside session (#2152)

* Add warning if primitive initalized outside session

* Release note

Author: kt474

qiskit_ibm_runtime/base_primitive.py

@@ -174,6 +174,14 @@ def _run(self, pubs: Union[list[EstimatorPub], list[SamplerPub]]) -> RuntimeJobV
             )
 
         if self._backend:
+            if get_cm_session():
+                logger.warning(
+                    "Even though a session/batch context manager is open this job will run in job mode "
+                    "because the %s primitive was initialized outside the context manager. "
+                    "Move the %s initialization inside the context manager to run in a session/batch.",
+                    self._program_id(),
+                    self._program_id(),
+                )
             runtime_options["backend"] = self._backend
             if "instance" not in runtime_options and isinstance(self._backend, IBMBackend):
                 runtime_options["instance"] = self._backend._instance

release-notes/unreleased/2152.feat.rst

@@ -0,0 +1,2 @@
+Added a warning for when a primitive is initialized outside of a session or batch context manager. 
+In this scenario, the job will run in job mode instead of the session or batch.