Deprecate qnode call shots= kwarg

doc/development/deprecations.rst

@@ -9,6 +9,12 @@ deprecations are listed below.
 Pending deprecations
 --------------------
 
+* ``shots=`` in ``QNode`` calls is deprecated and will be removed in v0.44.
+  Instead, please use the ``qml.workflow.set_shots`` transform to set the number of shots for a ``QNode``.
+
+  - Deprecated in v0.43
+  - Will be removed in v0.44
+
 * ``qml.qnn.cost.SquaredErrorLoss`` is deprecated and will be removed in version v0.44. Instead, this hybrid workflow can be accomplished 
   with a function like ``loss = lambda *args: (circuit(*args) - target)**2``.
 

doc/releases/changelog-dev.md

@@ -92,6 +92,10 @@
 
 <h3>Deprecations 👋</h3>
 
+* `shots=` in `QNode` calls is deprecated and will be removed in v0.44.
+  Instead, please use the `qml.workflow.set_shots` transform to set the number of shots for a QNode.
+  [(#7906)](https://github.com/PennyLaneAI/pennylane/pull/7906)
+
 * The `level=None` argument in the :func:`pennylane.workflow.get_transform_program`, :func:`pennylane.workflow.construct_batch`, `qml.draw`, `qml.draw_mpl`, and `qml.specs` transforms is deprecated and will be removed in v0.43.
   Please use `level='device'` instead to apply the noise model at the device level.
   [(#7886)](https://github.com/PennyLaneAI/pennylane/pull/7886)

pennylane/workflow/qnode.py

@@ -788,6 +788,10 @@ def construct(self, args, kwargs) -> qml.tape.QuantumScript:
         """Call the quantum function with a tape context, ensuring the operations get queued."""
         kwargs = copy.copy(kwargs)
         if "shots" in kwargs and self._shots_override_device:
+            warnings.warn(
+                "'shots' as an argument to the quantum function is deprecated and will be removed in v0.44. ",
+                PennyLaneDeprecationWarning,
+            )
             _kwargs_shots = kwargs.pop("shots")
             warnings.warn(
                 "Both 'shots=' parameter and 'set_shots' transform are specified. "

tests/test_qnode.py

@@ -2055,11 +2055,15 @@ def circuit():
 
         # Then try to pass shots parameter when calling the QNode
         with pytest.warns(
-            UserWarning,
-            match="Both 'shots=' parameter and 'set_shots' transform are specified. "
-            "The transform will take precedence over",
+            PennyLaneDeprecationWarning,
+            match="'shots' as an argument to the quantum function is deprecated",
         ):
-            result = modified_circuit(shots=25)
+            with pytest.warns(
+                UserWarning,
+                match="Both 'shots=' parameter and 'set_shots' transform are specified. "
+                "The transform will take precedence over",
+            ):
+                result = modified_circuit(shots=25)
 
         # Verify that the set_shots value (50) was used, not the parameter value (25)
         assert len(result) == 50
@@ -2332,8 +2336,5 @@ def circuit():
             return qml.sample(qml.PauliZ(0))
 
         # No warning should be raised when calling with the same shots value
-        with pytest.warns(
-            UserWarning, match="Both 'shots=' parameter and 'set_shots' transform are specified."
-        ):
-            result = circuit.update(diff_method="parameter-shift")(shots=50)
+        result = circuit.update(diff_method="parameter-shift")()
         assert len(result) == 100