feat: [FC-0074] add linter for Open edX Filters classes definitions

CHANGELOG.rst

@@ -13,6 +13,11 @@ Change Log
 Unreleased
 ~~~~~~~~~~
 
+5.6.0 - 2025-01-24
+~~~~~~~~~~~~~~~~~~
+
+* Add docstring linter for Open edX filters.
+
 5.5.0 - 2025-01-22
 ~~~~~~~~~~~~~~~~~~
 

edx_lint/__init__.py

@@ -2,4 +2,4 @@
 edx_lint standardizes lint configuration and additional plugins for use in
 Open edX code.
 """
-__version__ = "5.5.0"
+__version__ = "5.6.0"

edx_lint/pylint/filters_docstring/__init__.py

@@ -0,0 +1,10 @@
+"""
+edx_lint filters_docstring module (optional plugin for filters docstrings).
+
+Add this to your pylintrc::
+    load-plugins=edx_lint.pylint.filters_docstring
+"""
+
+from .filters_docstring_check import register_checkers
+
+register = register_checkers

edx_lint/pylint/filters_docstring/filters_docstring_check.py

@@ -0,0 +1,146 @@
+"""
+Pylint checker for the format of the docstrings of filters.
+
+A filter's docstring should have the following structure:
+
+1. Description: Any non-empty text followed by a blank line.
+2. Filter Type: A line that starts with "Filter Type:".
+3. Trigger: A line that starts with "Trigger:".
+"""
+
+import re
+
+from pylint.checkers import BaseChecker, utils
+
+from edx_lint.pylint.common import BASE_ID
+
+
+def register_checkers(linter):
+    """
+    Register checkers.
+    """
+    linter.register_checker(FiltersDocstringFormatChecker(linter))
+
+
+class FiltersDocstringFormatChecker(BaseChecker):
+    """Pylint checker for the format of the docstrings of filters."""
+
+    name = "filters-docstring-format"
+
+    DOCSTRING_MISSING_PURPOSE_OR_BADLY_FORMATTED = "filter-docstring-missing-purpose"
+    DOCSTRING_MISSING_OR_INCORRECT_TYPE = "filter-docstring-missing-or-incorrect-type"
+    DOCSTRING_MISSING_TRIGGER_OR_BADLY_FORMATTED = "filter-docstring-missing-trigger"
+
+    msgs = {
+        ("E%d91" % BASE_ID): (
+            "Filter's (%s) docstring is missing the required `Purpose` section or is badly formatted",
+            DOCSTRING_MISSING_PURPOSE_OR_BADLY_FORMATTED,
+            "filters docstring is missing the required `Purpose` section or is badly formatted",
+        ),
+        ("E%d93" % BASE_ID): (
+            "Filter's (%s) docstring `Filter Type` section is missing or incorrect",
+            DOCSTRING_MISSING_OR_INCORRECT_TYPE,
+            "filters docstring `Filter Type` section is missing or incorrect",
+        ),
+        ("E%d94" % BASE_ID): (
+            "Filter's (%s) docstring is missing the required `Trigger` section or is badly formatted",
+            DOCSTRING_MISSING_TRIGGER_OR_BADLY_FORMATTED,
+            "filters docstring is missing the required `Trigger` section or is badly formatted",
+        ),
+    }
+
+    @utils.only_required_for_messages(
+        DOCSTRING_MISSING_PURPOSE_OR_BADLY_FORMATTED,
+        DOCSTRING_MISSING_OR_INCORRECT_TYPE,
+        DOCSTRING_MISSING_TRIGGER_OR_BADLY_FORMATTED,
+    )
+    def visit_classdef(self, node):
+        """
+        Visit a class definition and check its docstring.
+
+        If the class is a subclass of OpenEdxPublicFilter, check the format of its docstring. Skip the
+        OpenEdxPublicFilter class itself.
+
+        """
+        if not node.is_subtype_of("openedx_filters.tooling.OpenEdxPublicFilter") or node.name == "OpenEdxPublicFilter":
+            return
+
+        docstring = node.doc_node.value if node.doc_node else ""
+        if not (error_messages := self._check_docstring_format(node, docstring)):
+            return
+        for error_message in error_messages:
+            self.add_message(error_message, node=node, args=(node.name,))
+
+    def _check_docstring_format(self, node, docstring):
+        """
+        Check the format of the docstring for errors and return a list of error messages.
+
+        The docstring should have the following structure:
+        1. Description: Any non-empty text followed by a blank line.
+        2. Filter Type: A line that starts with "Filter Type:".
+        3. Trigger: A line that starts with "Trigger:".
+
+        For example:
+
+        ```
+        Purpose:
+        Filter used to modify the certificate rendering process.
+
+        ... (more description)
+
+        Filter Type:
+            org.openedx.learning.certificate.render.started.v1
+
+        Trigger:
+            - Repository: openedx/edx-platform
+            - Path: lms/djangoapps/certificates/views/webview.py
+            - Function or Method: render_html_view
+        ```
+        """
+        error_messages = []
+        if error_message := self._check_purpose_missing_or_badly_formatted(docstring):
+            error_messages.append(error_message)
+        if error_message := self._check_filter_type_missing_or_incorrect(node, docstring):
+            error_messages.append(error_message)
+        if error_message := self._check_trigger_missing_or_badly_formatted(docstring):
+            error_messages.append(error_message)
+        return error_messages
+
+    def _check_purpose_missing_or_badly_formatted(self, docstring):
+        """
+        Check if the purpose is missing or badly formatted.
+
+        If the purpose is missing or badly formatted, return the error message. Otherwise, return.
+        """
+        if not re.search(r"Purpose:\s*.*\n", docstring):
+            return self.DOCSTRING_MISSING_PURPOSE_OR_BADLY_FORMATTED
+        return None
+
+    def _check_filter_type_missing_or_incorrect(self, node, docstring):
+        """
+        Check if the filter type is missing or incorrect.
+
+        If the filter type is missing or incorrect, return the error message. Otherwise, return.
+        """
+        filter_type = node.locals.get("filter_type")
+        if not filter_type:
+            return self.DOCSTRING_MISSING_OR_INCORRECT_TYPE
+
+        filter_type = filter_type[0].statement().value.value if filter_type else ""
+        if not re.search(r"Filter Type:\s*%s" % filter_type, docstring):
+            return self.DOCSTRING_MISSING_OR_INCORRECT_TYPE
+        return None
+
+    def _check_trigger_missing_or_badly_formatted(self, docstring):
+        """
+        Check if the trigger is missing or badly formatted.
+
+        If the trigger is missing or badly formatted, return the error message. Otherwise, return.
+        """
+        if not re.search(
+            r"Trigger:\s*(NA|-\s*Repository:\s*[^\n]+\s*-\s*Path:\s*[^\n]+\s*-\s*Function\s*or\s*Method:\s*[^\n]+)",
+            docstring,
+            re.MULTILINE,
+        ):
+            return self.DOCSTRING_MISSING_TRIGGER_OR_BADLY_FORMATTED
+        return None