MAINT: Add script for numpydoc linting of Public API

doc/numpydoc-public-api.py

@@ -0,0 +1,165 @@
+#!/usr/bin/env python
+"""A script that can be quickly run that explores the public API of Xarray
+and validates docstrings along the way according to the numpydoc conventions."""
+
+import functools
+import importlib
+import logging
+import sys
+import types
+from pathlib import Path
+
+from numpydoc.validate import validate
+
+logger = logging.getLogger("numpydoc-public-api")
+handler = logging.StreamHandler()
+handler.setFormatter(logging.Formatter("%(levelname)s: %(message)s"))
+logger.addHandler(handler)
+
+PROJECT_ROOT = (Path(__file__).parent / "..").resolve()
+PUBLIC_MODULES = ["xarray"]
+ROOT_PACKAGE = "xarray"
+
+# full list of numpydoc error codes: https://numpydoc.readthedocs.io/en/latest/validation.html
+SKIP_ERRORS = [ # TODO: Curate these for Xarray
+    "GL01",  # parcels is fine with the summary line starting directly after `"""`, or on the next line.
+    "SA01",  # Parcels doesn't require the "See also" section
+    "SA04",  #
+    "ES01",  # We don't require the extended summary for all docstrings
+    "EX01",  # We don't require the "Examples" section for all docstrings
+    "SS06",  # Not possible to make all summaries one line
+    #
+    # To be fixed up
+    "GL02",  # Closing quotes should be placed in the line after the last text in the docstring (do not close the quotes in the same line as the text, or leave a blank line between the last text and the quotes)
+    "GL03",  # Double line break found; please use only one blank line to separate sections or paragraphs, and do not leave blank lines at the end of docstrings
+    "GL07",  # Sections are in the wrong order. Correct order is: {correct_sections}
+    "GL08",  # The object does not have a docstring
+    "SS01",  # No summary found (a short summary in a single line should be present at the beginning of the docstring)
+    "SS02",  # Summary does not start with a capital letter
+    "SS03",  # Summary does not end with a period
+    "SS04",  # Summary contains heading whitespaces
+    "SS05",  # Summary must start with infinitive verb, not third person (e.g. use "Generate" instead of "Generates")
+    "PR01",  # Parameters {missing_params} not documented
+    "PR02",  # Unknown parameters {unknown_params}
+    "PR03",  # Wrong parameters order. Actual: {actual_params}. Documented: {documented_params}
+    "SA02",  # Missing period at end of description for See Also "{reference_name}" reference
+    "SA03",  # Description should be capitalized for See Also
+    #
+    # TODO consider whether to continue ignoring the following
+    "GL09",  # Deprecation warning should precede extended summary
+    "GL10",  # reST directives {directives} must be followed by two colons
+    "PR04",  # Parameter "{param_name}" has no type
+    "PR05",  # Parameter "{param_name}" type should not finish with "."
+    "PR06",  # Parameter "{param_name}" type should use "{right_type}" instead of "{wrong_type}"
+    "PR07",  # Parameter "{param_name}" has no description
+    "PR08",  # Parameter "{param_name}" description should start with a capital letter
+    "PR09",  # Parameter "{param_name}" description should finish with "."
+    "PR10",  # Parameter "{param_name}" requires a space before the colon separating the parameter name and type
+    "RT01",  # No Returns section found
+    "RT02",  # The first line of the Returns section should contain only the type, unless multiple values are being returned
+    "RT03",  # Return value has no description
+    "RT04",  # Return value description should start with a capital letter
+    "RT05",  # Return value description should finish with "."
+    "YD01",  # No Yields section found
+]
+
+
+def is_built_in(type_or_instance: type | object):
+    if isinstance(type_or_instance, type):
+        return type_or_instance.__module__ == "builtins"
+    else:
+        return type_or_instance.__class__.__module__ == "builtins"
+
+
+def walk_module(module_str: str, public_api: list[str] | None = None) -> list[str]:
+    if public_api is None:
+        public_api = []
+
+    module = importlib.import_module(module_str)
+    try:
+        all_ = module.__all__
+    except AttributeError:
+        print(f"No __all__ variable found in public module {module_str!r}")
+        return public_api
+
+    if module_str not in public_api:
+        public_api.append(module_str)
+    for item_str in all_:
+        item = getattr(module, item_str)
+        if isinstance(item, types.ModuleType):
+            walk_module(f"{module_str}.{item_str}", public_api)
+        if isinstance(item, (types.FunctionType,)):
+            public_api.append(f"{module_str}.{item_str}")
+        elif is_built_in(item):
+            print(f"Found builtin at '{module_str}.{item_str}' of type {type(item)}")
+            continue
+        elif isinstance(item, type):
+            public_api.append(f"{module_str}.{item_str}")
+            walk_class(module_str, item, public_api)
+        else:
+            logger.info(
+                f"Encountered unexpected public object at '{module_str}.{item_str}' of {item!r} in public API. Don't know how to handle with numpydoc - ignoring."
+            )
+
+    return public_api
+
+
+def get_public_class_attrs(class_: type) -> set[str]:
+    return {a for a in dir(class_) if not a.startswith("_")}
+
+
+def walk_class(module_str: str, class_: type, public_api: list[str]) -> list[str]:
+    class_str = class_.__name__
+
+    # attributes that were introduced by this class specifically - not from inheritance
+    attrs = get_public_class_attrs(class_) - functools.reduce(
+        set.union, (get_public_class_attrs(base) for base in class_.__bases__)
+    )
+
+    public_api.extend([f"{module_str}.{class_str}.{attr_str}" for attr_str in attrs])
+    return public_api
+
+
+def main():
+    import argparse
+
+    parser = argparse.ArgumentParser(description="Validate numpydoc docstrings in the public API")
+    parser.add_argument("-v", "--verbose", action="count", default=0, help="Increase verbosity (can be repeated)")
+    args = parser.parse_args()
+
+    # Set logging level based on verbosity: 0=WARNING, 1=INFO, 2+=DEBUG
+    if args.verbose == 0:
+        log_level = logging.WARNING
+    elif args.verbose == 1:
+        log_level = logging.INFO
+    else:
+        log_level = logging.DEBUG
+
+    logger.setLevel(log_level)
+
+    public_api = []
+    for module in PUBLIC_MODULES:
+        public_api += walk_module(module)
+
+    errors = 0
+    for item in public_api:
+        logger.info(f"Processing validating {item}")
+        try:
+            res = validate(item)
+        except (AttributeError, StopIteration, ValueError) as e:
+            if isinstance(e, ValueError) and "Error parsing See Also entry" in str(e): # TODO: Fix later https://github.com/pydata/xarray/issues/8596#issuecomment-3832443795
+                logger.info(f"Skipping See Also parsing error for {item!r}.")
+                continue
+            logger.warning(f"Could not process {item!r}. Encountered error. {e!r}")
+            continue
+        if res["type"] in ("module", "float", "int", "dict"):
+            continue
+        for err in res["errors"]:
+            if err[0] not in SKIP_ERRORS:
+                print(f"{item}: {err}")
+                errors += 1
+    sys.exit(errors)
+
+
+if __name__ == "__main__":
+    main()

doc/whats-new.rst

@@ -37,6 +37,8 @@ Performance
 
 Internal Changes
 ~~~~~~~~~~~~~~~~
+- Add script for linting of public docstrings according to numpydoc (:pull:`11121`).
+  By `Nick Hodgskin <https://github.com/VeckoTheGecko>`_.
 
 
 .. _whats-new.2026.01.0:

pixi.toml

@@ -329,6 +329,12 @@ policy = [
   ] },
 ]
 
+[feature.numpydoc-lint.dependencies]
+numpydoc = "*"
+
+[feature.numpydoc-lint.tasks]
+numpydoc-lint = { cmd = "python doc/numpydoc-public-api.py" }
+
 [environments]
 # Testing
 # test-just-xarray = { features = ["test"] } # https://github.com/pydata/xarray/pull/10888/files#r2511336147
@@ -441,3 +447,4 @@ default = { features = [
   "dev",
 ] }
 policy = { features = ["policy"], no-default-feature = true }
+numpydoc-lint = { features = ["numpydoc-lint"] }