Pre-commit hook for running numpydoc validation (#454)

* Add numpydoc.hooks directory.

* Add numpydoc.hooks to packages.

* Add tabulate dependency for use in validate hook.

* Add option to pass a Validator class to validate() function.

* Add AST-based validation logic to review files.

* Add entry point for validation hook.

* Add pre-commit hook configuration.

* Add SS05 match pattern for allowed verbs; add some type annotations.

* Add config option to override GL08 by name.

* Add option specify a path to a config file.

* Add information on the hook to the docs.

* Grab arg name off ast arg nodes for *args/**kwargs; don't alter filepath.

* Update spacing in example.

* Reduce maxcolwidths in report of findings by hook.

* Show file in a separate column of the findings; item is from module onward.

* Update example in docs for new column.

* Update example in docs for new column.

* Switch to a stack for visiting.

* Add line to file column; show module lineno as 1.

* Expand user on config file path.

* Use Path operations.

* Add support for using inline comments to ignore specific checks.

* Add support for comments at the end of a multiline declaration.

* Add a note on inline option to docs.

* Simplify check for the declaration start.

* Add support for reading hook config from pyproject.toml

* Add some initial tests for the validate hook.

* Tweak docstring.

* Add tests for hook using config files.

* Add finding of project root.

* Update link in docstring.

* Tweak code blocks in docs.

* Shorten table to avoid scroll in docs.

.pre-commit-hooks.yaml

@@ -0,0 +1,7 @@
+- id: numpydoc-validation
+  name: numpydoc-validation
+  description: This hook validates that docstrings in committed files adhere to numpydoc standards.
+  entry: validate-docstrings
+  require_serial: true
+  language: python
+  types: [python]

doc/validation.rst

@@ -2,6 +2,83 @@
 Validation
 ==========
 
+Docstring Validation using Pre-Commit Hook
+------------------------------------------
+
+To enable validation of docstrings as you commit files, add the
+following to your ``.pre-commit-config.yaml`` file:
+
+.. code-block:: yaml
+
+    - repo: https://github.com/numpy/numpydoc
+      rev: <version>
+      hooks:
+        - id: numpydoc-validation
+
+After installing ``numpydoc``, run the following to see available
+command line options for this hook:
+
+.. code-block:: bash
+
+    $ python -m numpydoc.hooks.validate_docstrings --help
+
+Using a config file provides additional customization. Both
+``pyproject.toml`` and ``setup.cfg`` are supported; however, if the
+project contains both you must use the ``pyproject.toml`` file.
+The example below configures the pre-commit hook to ignore three checks
+and specifies exceptions to the checks ``SS05`` (allow docstrings to
+start with "Process ", "Assess ", or "Access ") and ``GL08`` (allow
+the class/method/function with name "__init__" to not have a docstring).
+
+``pyproject.toml``::
+
+    [tool.numpydoc_validation]
+    ignore = [
+        "EX01",
+        "SA01",
+        "ES01",
+    ]
+    override_SS05 = '^((Process|Assess|Access) )'
+    override_GL08 = '^(__init__)$'
+
+``setup.cfg``::
+
+    [tool:numpydoc_validation]
+    ignore = EX01,SA01,ES01
+    override_SS05 = ^((Process|Assess|Access) )
+    override_GL08 = ^(__init__)$
+
+For more fine-tuned control, you can also include inline comments to tell the
+validation hook to ignore certain checks:
+
+.. code-block:: python
+
+    class SomeClass:  # numpydoc ignore=EX01,SA01,ES01
+        """This is the docstring for SomeClass."""
+
+        def __init__(self):  # numpydoc ignore=GL08
+            pass
+
+If any issues are found when commiting, a report is printed out and the
+commit is halted:
+
+.. code-block:: output
+
+    numpydoc-validation......................................................Failed
+    - hook id: numpydoc-validation
+    - exit code: 1
+
+    +----------------------+----------------------+---------+--------------------------------------+
+    | file                 | item                 | check   | description                          |
+    +======================+======================+=========+======================================+
+    | src/pkg/utils.py:1   | utils                | GL08    | The object does not have a docstring |
+    | src/pkg/utils.py:90  | utils.normalize      | PR04    | Parameter "field" has no type        |
+    | src/pkg/module.py:12 | module.MyClass       | GL08    | The object does not have a docstring |
+    | src/pkg/module.py:33 | module.MyClass.parse | RT03    | Return value has no description      |
+    +----------------------+----------------------+---------+--------------------------------------+
+
+See below for a full listing of checks.
+
 Docstring Validation using Python
 ---------------------------------
 

numpydoc/hooks/__init__.py

@@ -0,0 +1 @@
+"""Pre-commit hooks using numpydoc."""

numpydoc/hooks/utils.py

@@ -0,0 +1,48 @@
+"""Utility functions for pre-commit hooks."""
+
+import itertools
+import os
+from pathlib import Path
+from typing import Sequence
+
+
+def find_project_root(srcs: Sequence[str]):
+    """
+    Return a directory containing .git, .hg, pyproject.toml, or setup.cfg.
+
+    That directory can be one of the directories passed in ``srcs`` or their
+    common parent. If no directory in the tree contains a marker that would
+    specify it's the project root, the root of the file system is returned.
+
+    Parameters
+    ----------
+    srcs : Sequence[str]
+        The filepaths to run the hook on.
+
+    Returns
+    -------
+    str
+        The project root directory.
+
+    See Also
+    --------
+    black.find_project_root :
+        This function was adapted from
+        `Black <https://github.com/psf/black/blob/main/src/black/files.py>`_.
+    """
+    if not srcs:
+        return Path(".").resolve(), "current directory"
+
+    common_path = Path(
+        os.path.commonpath([Path(src).expanduser().resolve() for src in srcs])
+    )
+
+    for dir in itertools.chain([common_path], common_path.parents):
+        if (dir / "pyproject.toml").is_file():
+            return dir, "pyproject.toml"
+        if (dir / "setup.cfg").is_file():
+            return dir, "setup.cfg"
+        if (dir / ".git").exists() or (dir / ".hg").is_dir():
+            return dir, "version control"
+
+    return dir, "file system root"