Change DeprecationWarning and PendingDeprecationWarning to UserWarning (

#1211)

* increase stacklevel

* black

* Use UserWarning

* pytest warns

* adjust msg

* Update pennylane/_qubit_device.py

Co-authored-by: antalszava <antalszava@gmail.com>
Co-authored-by: Josh Izaac <josh146@gmail.com>

.github/CHANGELOG.md

@@ -701,7 +701,7 @@ fully differentiable.
   of shots is set explicitly.
 
 * If creating a QNode from a quantum function with an argument named `shots`,
-  a `DeprecationWarning` is raised, warning the user that this is a reserved
+  a `UserWarning` is raised, warning the user that this is a reserved
   argument to change the number of shots on a per-call basis.
   [(#1075)](https://github.com/PennyLaneAI/pennylane/pull/1075)
 

pennylane/_qubit_device.py

@@ -475,7 +475,7 @@ def sample_basis_states(self, number_of_states, state_probability):
                 "The number of shots has to be explicitly set on the device "
                 "when using sample-based measurements. Since no shots are specified, "
                 "a default of 1000 shots is used.",
-                DeprecationWarning,
+                UserWarning,
             )
 
         shots = self.shots or 1000

pennylane/devices/default_qubit_jax.py

@@ -247,8 +247,8 @@ def sample_basis_states(self, number_of_states, state_probability):
                 "The number of shots has to be explicitly set on the jax device "
                 "when using sample-based measurements. Since no shots are specified, "
                 "a default of 1000 shots is used.\n"
-                "This warning will replaced with an error in a future release.",
-                DeprecationWarning,
+                "This warning will be replaced with an error in a future release.",
+                UserWarning,
             )
 
         shots = self.shots or 1000

pennylane/qnode.py

@@ -157,7 +157,7 @@ def __init__(
                 "Detected 'shots' as an argument to the given quantum function. "
                 "The 'shots' argument name is reserved for overriding the number of shots "
                 "taken by the device. Its use outside of this context should be avoided.",
-                DeprecationWarning,
+                UserWarning,
             )
             self._qfunc_uses_shots_arg = True
         else:

pennylane/templates/embeddings/amplitude.py

@@ -131,7 +131,7 @@ def __init__(self, features, wires, pad_with=None, normalize=False, pad=None, do
         if pad is not None:
             warnings.warn(
                 "The pad argument will be replaced by the pad_with option in future versions of PennyLane.",
-                PendingDeprecationWarning,
+                UserWarning,
             )
             if pad_with is None:
                 pad_with = pad

pennylane/vqe/vqe.py

@@ -547,7 +547,7 @@ class VQECost(ExpvalCost):
     def __init__(self, *args, **kwargs):
         warnings.warn(
             "Use of VQECost is deprecated and should be replaced with ExpvalCost",
-            DeprecationWarning,
+            UserWarning,
             2,
         )
         super().__init__(*args, **kwargs)

tests/devices/test_default_qubit_jax.py

@@ -182,7 +182,9 @@ def test_sampling_analytic_mode(self):
         def circuit():
             return qml.sample(qml.PauliZ(wires=0))
 
-        with pytest.deprecated_call():
+        with pytest.warns(
+            UserWarning, match="The number of shots has to be explicitly set on the jax device"
+        ):
             res = circuit()
 
         assert len(res) == 1000

tests/tape/test_qnode.py

@@ -883,7 +883,7 @@ def circuit(a, shots=0):
             return qml.sample(qml.PauliZ(wires=0))
 
         with pytest.warns(
-            DeprecationWarning, match="The 'shots' argument name is reserved for overriding"
+            UserWarning, match="The 'shots' argument name is reserved for overriding"
         ):
             circuit = qml.QNode(circuit, dev)
 
@@ -909,7 +909,7 @@ def circuit(a, shots):
 
         # assert that warning is still raised
         with pytest.warns(
-            DeprecationWarning, match="The 'shots' argument name is reserved for overriding"
+            UserWarning, match="The 'shots' argument name is reserved for overriding"
         ):
             circuit = qml.QNode(circuit, dev)
 

tests/templates/test_embeddings/test_amplitude.py

@@ -239,7 +239,7 @@ def circuit(x=None):
             return qml.expval(qml.PauliZ(0))
 
         with pytest.warns(
-            PendingDeprecationWarning,
+            UserWarning,
             match="will be replaced by the pad_with option in future versions",
         ):
             circuit(x=inputs)

tests/test_qubit_device.py

@@ -414,7 +414,7 @@ def test_raises_deprecation_warning(self, mock_qubit_device, monkeypatch):
         state_probs = [0.1, 0.2, 0.3, 0.4]
 
         with pytest.warns(
-            DeprecationWarning, match="The number of shots has to be explicitly set on the device"
+            UserWarning, match="The number of shots has to be explicitly set on the device"
         ):
             dev.sample_basis_states(number_of_states, state_probs)
 

tests/test_vqe.py

@@ -1216,13 +1216,13 @@ def test_all_interfaces_gradient_agree(self, tol):
 
 
 def test_vqe_cost():
-    """Tests that VQECost raises a DeprecationWarning but otherwise behaves as ExpvalCost"""
+    """Tests that VQECost raises a UserWarning but otherwise behaves as ExpvalCost"""
 
     h = qml.Hamiltonian([1], [qml.PauliZ(0)])
     dev = qml.device("default.qubit", wires=1)
     ansatz = qml.templates.StronglyEntanglingLayers
 
-    with pytest.warns(DeprecationWarning, match="Use of VQECost is deprecated"):
+    with pytest.warns(UserWarning, match="Use of VQECost is deprecated"):
         cost = qml.VQECost(ansatz, h, dev)
 
     assert isinstance(cost, qml.ExpvalCost)