Replace pydocstyle with Ruff (#26) (#30)

Fixes #25 

Pydocstyle was deprecated in favor of Ruff. Ruff has the exact same lints via the `D` ruleset.

As before, we only run the doc checks on source code and not tests.<hr>This is an automatic backport of pull request #26 done by [Mergify](https://mergify.com).

docs/conf.py

@@ -140,6 +140,7 @@ def determine_github_branch() -> str:
 
 
 def linkcode_resolve(domain, info):
+    """Add links to GitHub source code."""
     if domain != "py":
         return None
 

pyproject.toml

@@ -59,11 +59,9 @@ style = [
 ]
 lint = [
     "qiskit-addon-obp[style]",
-    "pydocstyle==6.3.0",
     "mypy==1.11.2",
     "pylint==3.2.7",
     "reno>=4.1",
-    "toml>=0.9.6",
 ]
 notebook-dependencies = [
     "qiskit-addon-obp",
@@ -138,6 +136,7 @@ select = [
     "I",   # isort
     "E",   # pycodestyle
     "W",   # pycodestyle
+    "D",   # pydocstyle
     "F",   # pyflakes
     "RUF", # ruff
     "UP",  # pyupgrade
@@ -153,8 +152,12 @@ ignore = [
 max-args = 6
 
 [tool.ruff.lint.extend-per-file-ignores]
+"test/**.py" = [
+    "D",  # pydocstyle
+]
 "docs/**/*" = [
     "E402", # module level import not at top of file
+    "D100", # missing docstring in public module
 ]
 
 [tool.ruff.lint.flake8-copyright]
@@ -172,6 +175,9 @@ notice-rgx = """
 # that they have been altered from the originals\\.
 """
 
+[tool.ruff.lint.pydocstyle]
+convention = "google"
+
 [tool.typos.default.extend-words]
 IY = "IY"
 aer = "aer"

qiskit_addon_obp/backpropagation.py

@@ -52,8 +52,7 @@ def backpropagate(
     operator_budget: OperatorBudget | None = None,
     max_seconds: int | None = None,
 ) -> tuple[list[SparsePauliOp], Sequence[QuantumCircuit], OBPMetadata]:
-    """
-    Backpropagate slices of quantum circuit operations onto the provided observables.
+    """Backpropagate slices of quantum circuit operations onto the provided observables.
 
     This function takes a (list of) observable(s) and backpropagates the provided quantum circuit
     slices **in reverse order** onto the observable(s) until one of the stopping criteria is reached.
@@ -100,6 +99,7 @@ def backpropagate(
         ValueError: All observables and slices must act on equivalent numbers of qubits.
         ValueError: An input observable is larger than the constraints specified by ``operator_budget``.
         ValueError: ``operator_budget.max_paulis`` or ``operator_budget.max_qwc_groups`` is less than 1.
+
     """
     operator_budget = operator_budget or OperatorBudget()
     truncation_error_budget = truncation_error_budget or TruncationErrorBudget()

qiskit_addon_obp/utils/__init__.py

@@ -10,8 +10,7 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-"""
-Utility functionality for conducting operator backpropagation.
+"""Utility functionality for conducting operator backpropagation.
 
 .. currentmodule:: qiskit_addon_obp.utils
 

qiskit_addon_obp/utils/metadata.py

@@ -10,8 +10,7 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-"""
-Container classes for holding backpropagation metadata.
+"""Container classes for holding backpropagation metadata.
 
 .. currentmodule:: qiskit_addon_obp.utils.metadata
 
@@ -157,6 +156,7 @@ def accumulated_error(self, observable_idx: int, slice_idx: int | None = None) -
 
         Returns:
             The accumulated error computed per the explanations above.
+
         """
         if slice_idx is None:
             slice_idx = self.num_backpropagated_slices  # pragma: no cover
@@ -198,6 +198,7 @@ def left_over_error_budget(self, observable_idx: int, slice_idx: int | None = No
 
         Returns:
             The left-over error budget computed per the explanations above.
+
         """
         if slice_idx is None:
             slice_idx = self.num_backpropagated_slices  # pragma: no cover
@@ -238,6 +239,7 @@ def from_json(cls, json_file: str) -> OBPMetadata:
 
         Returns:
             The loaded metadata.
+
         """
         with open(json_file) as file:
             data = json.load(file)
@@ -260,6 +262,7 @@ def to_json(self, json_file: str, **kwargs) -> None:
         Args:
             json_file: the path to the file into which to dump the metadata.
             kwargs: keyword arguments to be passed on towards :meth:`.json.dump`.
+
         """
         with open(json_file, "w") as file:
             json.dump(asdict(self), file, **kwargs)

qiskit_addon_obp/utils/operations.py

@@ -10,8 +10,7 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-"""
-Utility functions for operator backpropagation.
+"""Utility functions for operator backpropagation.
 
 .. currentmodule:: qiskit_addon_obp.utils.operations
 
@@ -71,6 +70,7 @@ def apply_op_to(
     Raises:
         ValueError: The number of unique operator qargs must match the number of qubits in the
             corresponding operator.
+
     """
     _validate_qargs(op1, op1_qargs)
     _validate_qargs(op2, op2_qargs)
@@ -113,6 +113,7 @@ def to_global_op(op: SparsePauliOp, qargs: list[int], n_qubits: int) -> SparsePa
 
     Raises:
         ValueError: Qubit ID out of range
+
     """
     min_qargs = min(qargs)
     max_qargs = max(qargs)
@@ -135,8 +136,7 @@ def _validate_qargs(op: SparsePauliOp, qargs: list[int]) -> None:
 
 
 def reduce_op(global_op: SparsePauliOp) -> tuple[SparsePauliOp, list[int]]:
-    """
-    Create a lean representation of a global Pauli operator.
+    """Create a lean representation of a global Pauli operator.
 
     This function returns a lean representation of the input operator such that all
     of the qubits associated solely with Pauli-I terms have been removed. A list
@@ -161,6 +161,7 @@ def reduce_op(global_op: SparsePauliOp) -> tuple[SparsePauliOp, list[int]]:
 
     Raises:
         ValueError: Input operator may not be the identity operator.
+
     """
     pauli_strings = [p.to_label() for p in global_op.paulis]
     reduced_qargs = [
@@ -186,8 +187,7 @@ def apply_reset_to(
     qubit_id: int,
     inplace: bool = False,
 ) -> SparsePauliOp:
-    """
-    Apply a reset operation to a Pauli operator.
+    """Apply a reset operation to a Pauli operator.
 
     This function applies a reset operation to ``op`` in the following way:
 
@@ -204,6 +204,7 @@ def apply_reset_to(
 
     Returns:
         The transformed operator
+
     """
     if not inplace:
         op = op.copy()

qiskit_addon_obp/utils/simplify.py

@@ -10,8 +10,7 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-"""
-Functions for simplifying Pauli operators.
+"""Functions for simplifying Pauli operators.
 
 .. currentmodule:: qiskit_addon_obp.utils.simplify
 
@@ -100,6 +99,7 @@ def simplify(
 
     Returns:
         The simplified Pauli operator.
+
     """
     # Get default atol and rtol
     if atol is None:

qiskit_addon_obp/utils/truncating.py

@@ -10,8 +10,7 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-"""
-Functions for truncating Pauli operators within given error budgets.
+"""Functions for truncating Pauli operators within given error budgets.
 
 .. currentmodule:: qiskit_addon_obp.utils.truncating
 
@@ -115,6 +114,7 @@ def setup_budget(
 
     Raises:
         ValueError: if ``max_error_per_slice`` and ``max_error_total`` are both ``None``.
+
     """
     if max_error_per_slice is None and max_error_total is None:
         raise ValueError("max_error_per_slice and max_error_total may not both be None")
@@ -168,6 +168,7 @@ def truncate_binary_search(
         .. note::
            The incurred truncation error bound, :math:`E`, is calculated as the ``p-norm`` of the
            truncated terms' coefficient magnitudes, :math:`c`, such that :math:`E = \|c\|_p`.
+
     """
     abscs = np.abs(observable.coeffs) ** p_norm
 

qiskit_addon_obp/utils/visualization.py

@@ -10,8 +10,7 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-"""
-Various visualization utilities.
+"""Various visualization utilities.
 
 .. currentmodule:: qiskit_addon_obp.utils.visualization
 
@@ -72,6 +71,7 @@ def plot_accumulated_error(metadata: OBPMetadata, axes: Axes) -> None:
     Args:
         metadata: the metadata to be visualized.
         axes: the matplotlib axes in which to plot.
+
     """
     if not np.isinf(metadata.truncation_error_budget.max_error_total):
         axes.axhline(
@@ -127,6 +127,7 @@ def plot_left_over_error_budget(metadata: OBPMetadata, axes: Axes) -> None:
     Args:
         metadata: the metadata to be visualized.
         axes: the matplotlib axes in which to plot.
+
     """
     for obs_idx in range(len(metadata.backpropagation_history[0].slice_errors)):
         axes.plot(
@@ -176,6 +177,7 @@ def plot_slice_errors(metadata: OBPMetadata, axes: Axes) -> None:
     Args:
         metadata: the metadata to be visualized.
         axes: the matplotlib axes in which to plot.
+
     """
     num_observables = len(metadata.backpropagation_history[0].slice_errors)
     width = 0.8 / num_observables
@@ -229,6 +231,7 @@ def plot_num_paulis(metadata: OBPMetadata, axes: Axes) -> None:
     Args:
         metadata: the metadata to be visualized.
         axes: the matplotlib axes in which to plot.
+
     """
     for obs_idx in range(len(metadata.backpropagation_history[0].slice_errors)):
         axes.plot(
@@ -275,6 +278,7 @@ def plot_num_truncated_paulis(metadata: OBPMetadata, axes: Axes) -> None:
     Args:
         metadata: the metadata to be visualized.
         axes: the matplotlib axes in which to plot.
+
     """
     num_observables = len(metadata.backpropagation_history[0].slice_errors)
     width = 0.8 / num_observables
@@ -329,6 +333,7 @@ def plot_sum_paulis(metadata: OBPMetadata, axes: Axes) -> None:
     Args:
         metadata: the metadata to be visualized.
         axes: the matplotlib axes in which to plot.
+
     """
     if metadata.operator_budget.max_paulis is not None:
         axes.axhline(
@@ -380,6 +385,7 @@ def plot_num_qwc_groups(metadata: OBPMetadata, axes: Axes) -> None:
     Args:
         metadata: the metadata to be visualized.
         axes: the matplotlib axes in which to plot.
+
     """
     if metadata.operator_budget.max_qwc_groups is not None:
         axes.axhline(

test/test_backpropagation.py

@@ -597,7 +597,6 @@ def test_backpropagate(self):
 
     def test_backpropagate_multi(self):
         """Tests back-propagation into multiple observables."""
-
         with self.subTest("Single slice"):
             theta = np.pi / 6
             qc_mat = np.array(

tox.ini

@@ -29,7 +29,6 @@ commands =
   ruff check qiskit_addon_obp/ docs/ test/
   ruff check --preview --select CPY001 --exclude "*.ipynb" qiskit_addon_obp/ test/
   nbqa ruff docs/
-  pydocstyle qiskit_addon_obp/
   mypy qiskit_addon_obp/
   pylint -rn qiskit_addon_obp/ test/
   nbqa pylint -rn docs/