Rule to drop 'Rule' suffix from rule names

ghstack-source-id: eef0464
Pull Request resolved: #350

Author: amyreese

docs/guide/builtins.rst

@@ -1269,6 +1269,7 @@ Built-in Rules
 .. automodule:: fixit.upgrade
 
 - :class:`FixitDeprecatedImport`
+- :class:`FixitRemoveRuleSuffix`
 
 .. class:: FixitDeprecatedImport
 
@@ -1307,4 +1308,34 @@ Built-in Rules
             # suggested fix
             from fixit import LintRule
 
+.. class:: FixitRemoveRuleSuffix
+
+    Remove the "Rule" suffix from lint rule class names
+
+    .. attribute:: MESSAGE
+
+        Do not end lint rule subclasses with 'Rule'
+
+
+    .. attribute:: VALID
+
+        .. code:: python
+
+            import fixit
+            class DontTryThisAtHome(fixit.LintRule): ...
+        .. code:: python
+
+            from fixit import LintRule
+            class CatsRuleDogsDrool(LintRule): ...
+
+    .. attribute:: INVALID
+
+        .. code:: python
+
+            import fixit
+            class DontTryThisAtHomeRule(fixit.LintRule): ...
+        .. code:: python
+
+            from fixit import LintRule
+            class CatsRuleDogsDroolRule(LintRule): ...
     

src/fixit/upgrade/remove_rule_suffix.py

@@ -0,0 +1,63 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import libcst
+from libcst.metadata import FullyQualifiedNameProvider
+
+from fixit import Invalid, LintRule, Valid
+
+
+class FixitRemoveRuleSuffix(LintRule):
+    """
+    Remove the "Rule" suffix from lint rule class names
+    """
+
+    MESSAGE = "Do not end lint rule subclasses with 'Rule'"
+    METADATA_DEPENDENCIES = (FullyQualifiedNameProvider,)
+
+    VALID = [
+        Valid(
+            """
+            import fixit
+            class DontTryThisAtHome(fixit.LintRule): ...
+            """
+        ),
+        Valid(
+            """
+            from fixit import LintRule
+            class CatsRuleDogsDrool(LintRule): ...
+            """
+        ),
+        Valid(
+            """
+            class NotALintRule: ...
+            """
+        ),
+    ]
+    INVALID = [
+        Invalid(
+            """
+            import fixit
+            class DontTryThisAtHomeRule(fixit.LintRule): ...
+            """
+        ),
+        Invalid(
+            """
+            from fixit import LintRule
+            class CatsRuleDogsDroolRule(LintRule): ...
+            """
+        ),
+    ]
+
+    def visit_ClassDef(self, node: libcst.ClassDef) -> None:
+        for base in node.bases:
+            metadata = self.get_metadata(FullyQualifiedNameProvider, base.value)
+            if isinstance(metadata, set):
+                qname = metadata.pop().name
+                if qname == "fixit.LintRule":
+                    rule_name = node.name.value
+                    if rule_name.endswith("Rule"):
+                        rep = node.name.with_changes(value=rule_name[:-4])
+                        self.report(node.name, replacement=rep)