Implement a checker to validate that q uses SearchFIlter

pylint_nautobot/__init__.py

@@ -8,6 +8,7 @@
 from .deprecated_status_model import NautobotDeprecatedStatusModelChecker
 from .incorrect_base_class import NautobotIncorrectBaseClassChecker
 from .model_label import NautobotModelLabelChecker
+from .q_search_filter import NautobotUseSearchFilterChecker
 from .replaced_models import NautobotReplacedModelsImportChecker
 from .string_field_blank_null import NautobotStringFieldBlankNull
 from .sub_class_name import NautobotSubClassNameChecker
@@ -22,6 +23,7 @@
     NautobotIncorrectBaseClassChecker,
     NautobotModelLabelChecker,
     NautobotReplacedModelsImportChecker,
+    NautobotUseSearchFilterChecker,
     NautobotStringFieldBlankNull,
     NautobotSubClassNameChecker,
     NautobotUseFieldsAllChecker,

pylint_nautobot/q_search_filter.py

@@ -0,0 +1,48 @@
+"""Check for use of SearchFilter on NautobotFilterSets instead of custom `q` search functions."""
+
+from astroid import Assign, AssignName, ClassDef
+from pylint.checkers import BaseChecker
+
+from .utils import is_version_compatible
+
+_META_CLASSES = {
+    "nautobot.extras.filters.NautobotFilterSet": ">1",
+    "nautobot.apps.filters.NautobotFilterSet": ">1",
+}
+
+
+class NautobotUseSearchFilterChecker(BaseChecker):
+    """Visit NautobotFilterSet subclasses and check for use of `q = SearchFilter`, instead of `q = django_filters.CharField`."""
+
+    version_specifier = ">=2,<3"
+
+    name = "nautobot-use-search-filter"
+    msgs = {
+        "C4272": (
+            "Use `q = SearchFilter` instead of django_filters.CharField and the custom `search` function.",
+            "nb-use-search-filter",
+            "Nautobot provides a `SearchFilter` class that uses MappedPredicates to provide a more flexible search experience. "
+            "This should be used in place of `django_filters.CharFilter` and no longer requires the custom `search` function.",
+        ),
+    }
+
+    def __init__(self, *args, **kwargs):
+        """Initialize the checker."""
+        super().__init__(*args, **kwargs)
+
+        self.meta_classes = [
+            key for key, specifier_set in _META_CLASSES.items() if is_version_compatible(specifier_set)
+        ]
+
+    def visit_classdef(self, node: ClassDef):
+        """Visit class definitions."""
+        if not any(ancestor.qname() in self.meta_classes for ancestor in node.ancestors()):
+            return
+
+        for child_node in node.get_children():
+            if isinstance(child_node, Assign):
+                if any(isinstance(target, AssignName) and target.name == "q" for target in child_node.targets):
+                    # because they can be ast Name or Attribute nodes
+                    child_node_name = child_node.value.func.as_string().split(".")[-1]
+                    if child_node_name != "SearchFilter":
+                        self.add_message("nb-use-search-filter", node=child_node)