MAINT: Changed class constructor __init__ GL08 reporting (#592)

Co-authored-by: Stefan van der Walt <sjvdwalt@gmail.com>
Co-authored-by: Eric Larson <larson.eric.d@gmail.com>

doc/format.rst

@@ -557,7 +557,9 @@ Class docstring
 Use the same sections as outlined above (all except :ref:`Returns <returns>`
 are applicable).  The constructor (``__init__``) should also be documented
 here, the :ref:`Parameters <params>` section of the docstring details the
-constructor's parameters.
+constructor's parameters. While repetition is unnecessary, a docstring for
+the class constructor (``__init__``) can, optionally, be added to provide
+detailed initialization documentation.
 
 An **Attributes** section, located below the :ref:`Parameters <params>`
 section, may be used to describe non-method attributes of the class::

doc/validation.rst

@@ -183,6 +183,9 @@ inline comments:
         def __init__(self):  # numpydoc ignore=GL08
             pass
 
+Note that a properly formatted :ref:`class <classdoc>` docstring
+silences ``G08`` for an ``__init__`` constructor without a docstring.
+
 This is supported by the :ref:`CLI <validation_via_cli>`,
 :ref:`pre-commit hook <pre_commit_hook>`, and
 :ref:`Sphinx extension <validation_during_sphinx_build>`.

numpydoc/tests/test_validate.py

@@ -1198,6 +1198,113 @@ def missing_whitespace_after_comma(self):
         """
 
 
+class ConstructorDocumentedInClassAndInit:
+    """
+    Class to test constructor documented via class and constructor docstrings.
+
+    A case where both the class docstring and the constructor docstring are
+    defined.
+
+    Parameters
+    ----------
+    param1 : int
+        Description of param1.
+
+    See Also
+    --------
+    otherclass : A class that does something else.
+
+    Examples
+    --------
+    This is an example of how to use ConstructorDocumentedInClassAndInit.
+    """
+
+    def __init__(self, param1: int) -> None:
+        """
+        Constructor docstring with additional information.
+
+        Extended information.
+
+        Parameters
+        ----------
+        param1 : int
+            Description of param1 with extra details.
+
+        See Also
+        --------
+        otherclass : A class that does something else.
+
+        Examples
+        --------
+        This is an example of how to use ConstructorDocumentedInClassAndInit.
+        """
+
+
+class ConstructorDocumentedInClass:
+    """
+    Class to test constructor documented via class docstring.
+
+    Useful to ensure that validation of `__init__` does not signal GL08,
+    when the class docstring properly documents the `__init__` constructor.
+
+    Parameters
+    ----------
+    param1 : int
+        Description of param1.
+
+    See Also
+    --------
+    otherclass : A class that does something else.
+
+    Examples
+    --------
+    This is an example of how to use ConstructorDocumentedInClass.
+    """
+
+    def __init__(self, param1: int) -> None:
+        pass
+
+
+class ConstructorDocumentedInClassWithNoParameters:
+    """
+    Class to test constructor documented via class docstring with no parameters.
+
+    Useful to ensure that validation of `__init__` does not signal GL08,
+    when the class docstring properly documents the `__init__` constructor.
+
+    See Also
+    --------
+    otherclass : A class that does something else.
+
+    Examples
+    --------
+    This is an example of how to use ConstructorDocumentedInClassWithNoParameters.
+    """
+
+    def __init__(self) -> None:
+        pass
+
+
+class IncompleteConstructorDocumentedInClass:
+    """
+    Class to test an incomplete constructor docstring.
+
+    This class does not properly document parameters.
+    Unnecessary extended summary.
+
+    See Also
+    --------
+    otherclass : A class that does something else.
+
+    Examples
+    --------
+    This is an example of how to use IncompleteConstructorDocumentedInClass.
+    """
+
+    def __init__(self, param1: int):
+        pass
+
+
 class TestValidator:
     def _import_path(self, klass=None, func=None):
         """
@@ -1536,6 +1643,40 @@ def test_bad_docstrings(self, capsys, klass, func, msgs):
         for msg in msgs:
             assert msg in " ".join(err[1] for err in result["errors"])
 
+    @pytest.mark.parametrize(
+        "klass,exp_init_codes,exc_init_codes,exp_klass_codes",
+        [
+            ("ConstructorDocumentedInClass", tuple(), ("GL08",), tuple()),
+            ("ConstructorDocumentedInClassAndInit", tuple(), ("GL08",), tuple()),
+            (
+                "ConstructorDocumentedInClassWithNoParameters",
+                tuple(),
+                ("GL08",),
+                tuple(),
+            ),
+            (
+                "IncompleteConstructorDocumentedInClass",
+                ("GL08",),
+                tuple(),
+                ("PR01"),  # Parameter not documented in class constructor
+            ),
+        ],
+    )
+    def test_constructor_docstrings(
+        self, klass, exp_init_codes, exc_init_codes, exp_klass_codes
+    ):
+        # First test the class docstring itself, checking expected_klass_codes match
+        result = validate_one(self._import_path(klass=klass))
+        for err in result["errors"]:
+            assert err[0] in exp_klass_codes
+
+        # Then test the constructor docstring
+        result = validate_one(self._import_path(klass=klass, func="__init__"))
+        for code in exp_init_codes:
+            assert code in " ".join(err[0] for err in result["errors"])
+        for code in exc_init_codes:
+            assert code not in " ".join(err[0] for err in result["errors"])
+
 
 def decorator(x):
     """Test decorator."""

numpydoc/validate.py

@@ -637,7 +637,29 @@ def validate(obj_name, validator_cls=None, **validator_kwargs):
 
     errs = []
     if not doc.raw_doc:
-        if "GL08" not in ignore_validation_comments:
+        report_GL08: bool = True
+        # Check if the object is a class and has a docstring in the constructor
+        # Also check if code_obj is defined, as undefined for the AstValidator in validate_docstrings.py.
+        if (
+            doc.name.endswith(".__init__")
+            and doc.is_function_or_method
+            and hasattr(doc, "code_obj")
+        ):
+            cls_name = doc.code_obj.__qualname__.split(".")[0]
+            cls = Validator._load_obj(f"{doc.code_obj.__module__}.{cls_name}")
+            # cls = Validator._load_obj(f"{doc.name[:-9]}.{cls_name}") ## Alternative
+            cls_doc = Validator(get_doc_object(cls))
+
+            # Parameter_mismatches, PR01, PR02, PR03 are checked for the class docstring.
+            # If cls_doc has PR01, PR02, PR03 errors, i.e. invalid class docstring,
+            # then we also report missing constructor docstring, GL08.
+            report_GL08 = len(cls_doc.parameter_mismatches) > 0
+
+        # Check if GL08 is to be ignored:
+        if "GL08" in ignore_validation_comments:
+            report_GL08 = False
+        # Add GL08 error?
+        if report_GL08:
             errs.append(error("GL08"))
         return {
             "type": doc.type,