Add pylint to workflow tests (#520)

* updat format workflow

* add install instruction

* update `.pylintrc` files

* add `pylint` fixes

* tweaks

* tweaks

* workflow name

* copyright dates

* Update tests/conftest.py

* apply suggestions

* minor tweak

.github/workflows/format.yml

@@ -3,7 +3,7 @@ on:
 - pull_request
 
 jobs:
-  black:
+  black-pylint:
     runs-on: ubuntu-latest
     steps:
       - name: Cancel Previous Runs
@@ -17,9 +17,19 @@ jobs:
           python-version: 3.9
 
       - name: Install dependencies
-        run: pip install black
+        run: pip install black pylint==2.7.4
 
       - uses: actions/checkout@v2
 
       - name: Run Black
-        run: black -l 100 pennylane_qiskit/ --check
+        run: | 
+          black -l 100 pennylane_qiskit/ --check
+          black -l 100 tests/ --check
+
+      - name: Run Pylint (source files)
+        if: always()
+        run: pylint --rcfile .pylintrc $(find pennylane_qiskit -name "*.py")
+
+      - name: Run Pylint (test files)
+        if: always()
+        run: pylint --rcfile tests/.pylintrc $(find tests -name "*.py")

.pylintrc

@@ -2,20 +2,20 @@
 # A comma-separated list of packages or module names from where C extensions may
 # be loaded. Extensions are loaded into the active Python interpreter and may
 # run arbitrary code
-extension-pkg-whitelist=numpy,scipy,autograd,qiskit
+extension-pkg-whitelist=numpy,scipy,autograd,qiskit,pennylane,sympy,qiskit_ibm_runtime,qiskit_ibm_provider,semantic_version
 
 [TYPECHECK]
 
 # List of module names for which member attributes should not be checked
 # (useful for modules/projects where namespaces are manipulated during runtime
 # and thus existing member attributes cannot be deduced by static analysis. It
 # supports qualified module names, as well as Unix pattern matching.
-ignored-modules=numpy,scipy,autograd,qiskit
+ignored-modules=numpy,scipy,autograd,qiskit,pennylane,sympy,qiskit_ibm_runtime,qiskit_ibm_provider,semantic_version
 
 # List of class names for which member attributes should not be checked
 # (useful for classes with attributes dynamically set). This can work
 # with qualified names.
-ignored-classes=numpy,scipy,autograd,qiskit
+ignored-classes=numpy,scipy,autograd,qiskit,pennylane,sympy,qiskit_ibm_runtime,qiskit_ibm_provider,semantic_version
 
 [MESSAGES CONTROL]
 
@@ -28,4 +28,18 @@ ignored-classes=numpy,scipy,autograd,qiskit
 # can either give multiple identifiers separated by comma (,) or put this option
 # multiple times (only on the command line, not in the configuration file where
 # it should appear only once).
-disable=line-too-long,invalid-name,too-many-lines,redefined-builtin,too-many-locals,duplicate-code,bad-continuation
+disable=
+  line-too-long,
+  invalid-name,
+  too-many-lines,
+  redefined-builtin,
+  too-many-locals,
+  duplicate-code,
+  cyclic-import,
+  import-error,
+  bad-option-value
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+notes=

pennylane_qiskit/converter.py

@@ -446,6 +446,7 @@ def _function(*args, params: dict = None, wires: list = None, **kwargs):
         mid_circ_regs = {}
 
         # Processing the dictionary of parameters passed
+        # pylint: disable=too-many-nested-blocks
         for idx, circuit_instruction in enumerate(qc.data):
             (instruction, qargs, cargs) = circuit_instruction
             # the new Singleton classes have different names than the objects they represent,

pennylane_qiskit/qiskit_device.py

@@ -266,6 +266,7 @@ def backend(self):
         return self._backend
 
     def reset(self):
+        """Reset the Qiskit backend device"""
         # Reset only internal data, not the options that are determined on
         # device creation
         self._reg = QuantumRegister(self.num_wires, "q")
@@ -305,6 +306,7 @@ def create_circuit_object(self, operations, **kwargs):
             self._circuit.save_state()
 
     def apply(self, operations, **kwargs):
+        """Build the circuit object and apply the operations"""
         self.create_circuit_object(operations, **kwargs)
 
         # These operations need to run for all devices
@@ -448,9 +450,11 @@ def generate_samples(self, circuit=None):
 
     @property
     def state(self):
+        """Get state of the device"""
         return self._state
 
     def analytic_probability(self, wires=None):
+        """Get the analytic probability of the device"""
         if self._state is None:
             return None
 
@@ -482,7 +486,7 @@ def compile_circuits(self, circuits):
         return compiled_circuits
 
     def batch_execute(self, circuits, timeout: int = None):
-        # pylint: disable=missing-function-docstring
+        """Batch execute the circuits on the device"""
 
         compiled_circuits = self.compile_circuits(circuits)
 
@@ -500,6 +504,7 @@ def batch_execute(self, circuits, timeout: int = None):
             result = self._current_job.result()
 
         # increment counter for number of executions of qubit device
+        # pylint: disable=no-member
         self._num_executions += 1
 
         # Compute statistics using the state and/or samples

pennylane_qiskit/runtime_devices.py

@@ -193,6 +193,7 @@ def batch_execute(self, circuits):
 
         return results
 
+    # pylint: disable=arguments-differ
     def generate_samples(self, circuit_id=None):
         r"""Returns the computational basis samples generated for all wires.
 

tests/.pylintrc

@@ -0,0 +1,58 @@
+[MASTER]
+# A comma-separated list of package or module names from where C extensions may
+# be loaded. Extensions are loading into the active Python interpreter and may
+# run arbitrary code
+extension-pkg-whitelist=numpy,scipy,autograd,qiskit,pennylane,sympy,qiskit_ibm_runtime,qiskit_ibm_provider,semantic_version
+
+[TYPECHECK]
+
+# List of module names for which member attributes should not be checked
+# (useful for modules/projects where namespaces are manipulated during runtime
+# and thus existing member attributes cannot be deduced by static analysis. It
+# supports qualified module names, as well as Unix pattern matching.
+ignored-modules=numpy,scipy,autograd,qiskit,pennylane,sympy,qiskit_ibm_runtime,qiskit_ibm_provider,semantic_version
+
+# List of classes names for which member attributes should not be checked
+# (useful for classes with attributes dynamically set). This supports can work
+# with qualified names.
+ignored-classes=numpy,scipy,autograd,qiskit,pennylane,sympy,qiskit_ibm_runtime,qiskit_ibm_provider,semantic_version
+
+[MESSAGES CONTROL]
+
+# Enable the message, report, category or checker with the given id(s). You can
+# either give multiple identifier separated by comma (,) or put this option
+# multiple time.
+#enable=
+
+# Disable the message, report, category or checker with the given id(s). You
+# can either give multiple identifier separated by comma (,) or put this option
+# multiple time (only on the command line, not in the configuration file where
+# it should appear only once).
+# Cyclical import checks are disabled for now as they are frequently used in
+# the code base, but this can be removed in the future once cycles are resolved.
+disable=
+  line-too-long,
+  invalid-name,
+  too-many-lines,
+  redefined-builtin,
+  too-many-locals,
+  duplicate-code,
+  cyclic-import,
+  import-error,
+  bad-option-value,
+  import-outside-toplevel,
+  missing-class-docstring,
+  missing-function-docstring,
+  no-self-use,
+  no-member, # because of qnode decorator
+  comparison-with-callable,
+  unsubscriptable-object, # because of qnode decorator
+  not-callable, # because of qnode decorator
+  unexpected-keyword-arg,
+  arguments-differ,
+  no-value-for-parameter
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+notes=

tests/conftest.py

@@ -1,4 +1,4 @@
-# Copyright 2021-2022 Xanadu Quantum Technologies Inc.
+# Copyright 2021-2024 Xanadu Quantum Technologies Inc.
 
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 r"""
-This module contains tests for PennyLane runtime programs.
+This module contains some configuration for PennyLane IBMQ devices.
 """
 
 import os
@@ -22,9 +22,11 @@
 
 import pennylane as qml
 from semantic_version import Version
-from qiskit_ibm_provider import IBMProvider
+from qiskit_ibm_provider import IBMProvider, IBMProviderValueError
 from pennylane_qiskit import AerDevice, BasicAerDevice, BasicSimulatorDevice
 
+# pylint: disable=protected-access, unused-argument, redefined-outer-name
+
 np.random.seed(42)
 
 U = np.array(
@@ -61,7 +63,7 @@ def skip_if_no_account():
     t = os.getenv("IBMQX_TOKEN", None)
     try:
         IBMProvider(token=t)
-    except Exception:
+    except IBMProviderValueError:
         missing = "token" if t else "account"
         pytest.skip(f"Skipping test, no IBMQ {missing} available")
 

tests/test_apply.py

@@ -1,15 +1,30 @@
+# Copyright 2021-2024 Xanadu Quantum Technologies Inc.
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+r"""
+This module contains tests for applying operations on PennyLane IBMQ devices.
+"""
 import pytest
 
 import numpy as np
 import pennylane as qml
 from scipy.linalg import block_diag
 
-from pennylane_qiskit import AerDevice, BasicAerDevice
-
 from conftest import U, U2
 
-np.random.seed(42)
+# pylint: disable=protected-access, too-many-arguments, too-few-public-methods
 
+np.random.seed(42)
 
 # global variables and rotations
 I = np.identity(2)
@@ -26,7 +41,7 @@
 toffoli[6:8, 6:8] = np.array([[0, 1], [1, 0]])
 CSWAP = block_diag(I, I, SWAP)
 
-
+# pylint: disable=unnecessary-lambda-assignment
 phase_shift = lambda phi: np.array([[1, 0], [0, np.exp(1j * phi)]])
 rx = lambda theta: np.cos(theta / 2) * I + 1j * np.sin(-theta / 2) * X
 ry = lambda theta: np.cos(theta / 2) * I + 1j * np.sin(-theta / 2) * Y