New codemod to add missing self/cls

integration_tests/test_fix_missing_self_or_cls.py

@@ -0,0 +1,47 @@
+from codemodder.codemods.test import (
+    BaseIntegrationTest,
+    original_and_expected_from_code_path,
+)
+from core_codemods.fix_missing_self_or_cls import (
+    FixMissingSelfOrCls,
+    FixMissingSelfOrClsTransformer,
+)
+
+
+class TestFixMissingSelfOrCls(BaseIntegrationTest):
+    codemod = FixMissingSelfOrCls
+    code_path = "tests/samples/fix_missing_self_or_cls.py"
+    original_code, expected_new_code = original_and_expected_from_code_path(
+        code_path,
+        [
+            (
+                1,
+                """    def instance_method(self):\n""",
+            ),
+            (
+                5,
+                """    def class_method(cls):\n""",
+            ),
+        ],
+    )
+
+    # fmt: off
+    expected_diff = (
+    """--- \n"""
+    """+++ \n"""
+    """@@ -1,7 +1,7 @@\n"""
+    """ class MyClass:\n"""
+    """-    def instance_method():\n"""
+    """+    def instance_method(self):\n"""
+    """         print("instance_method")\n"""
+    """ \n"""
+    """     @classmethod\n"""
+    """-    def class_method():\n"""
+    """+    def class_method(cls):\n"""
+    """         print("class_method")\n"""
+    )
+    # fmt: on
+
+    expected_line_change = "2"
+    change_description = FixMissingSelfOrClsTransformer.change_description
+    num_changes = 2

integration_tests/test_sonar_fix_missing_self_or_cls.py

@@ -0,0 +1,45 @@
+from codemodder.codemods.test import (
+    BaseIntegrationTest,
+    original_and_expected_from_code_path,
+)
+from core_codemods.fix_missing_self_or_cls import FixMissingSelfOrClsTransformer
+from core_codemods.sonar.sonar_fix_missing_self_or_cls import SonarFixMissingSelfOrCls
+
+
+class TestSonarFixMissingSelfOrCls(BaseIntegrationTest):
+    codemod = SonarFixMissingSelfOrCls
+    code_path = "tests/samples/fix_missing_self_or_cls.py"
+    original_code, expected_new_code = original_and_expected_from_code_path(
+        code_path,
+        [
+            (
+                1,
+                """    def instance_method(self):\n""",
+            ),
+            (
+                5,
+                """    def class_method(cls):\n""",
+            ),
+        ],
+    )
+    sonar_issues_json = "tests/samples/sonar_issues.json"
+    # fmt: off
+    expected_diff = (
+    """--- \n"""
+    """+++ \n"""
+    """@@ -1,7 +1,7 @@\n"""
+    """ class MyClass:\n"""
+    """-    def instance_method():\n"""
+    """+    def instance_method(self):\n"""
+    """         print("instance_method")\n"""
+    """ \n"""
+    """     @classmethod\n"""
+    """-    def class_method():\n"""
+    """+    def class_method(cls):\n"""
+    """         print("class_method")\n"""
+    )
+    # fmt: on
+
+    expected_line_change = "2"
+    change_description = FixMissingSelfOrClsTransformer.change_description
+    num_changes = 2

src/codemodder/codemods/utils_mixin.py

@@ -277,6 +277,18 @@ def is_builtin_function(self, node: cst.Call):
             return matchers.matches(node.func, matchers.Name())
         return False
 
+    def is_staticmethod(self, node: cst.FunctionDef) -> bool:
+        for decorator in node.decorators:
+            if self.find_base_name(decorator.decorator) == "builtins.staticmethod":
+                return True
+        return False
+
+    def is_classmethod(self, node: cst.FunctionDef) -> bool:
+        for decorator in node.decorators:
+            if self.find_base_name(decorator.decorator) == "builtins.classmethod":
+                return True
+        return False
+
     def find_accesses(self, node) -> Collection[Access]:
         if scope := self.get_metadata(ScopeProvider, node, None):
             return scope.accesses[node]
@@ -437,10 +449,10 @@ def find_immediate_class_def(self, node: cst.CSTNode) -> Optional[cst.ClassDef]:
 
     def path_to_root(self, node: cst.CSTNode) -> list[cst.CSTNode]:
         """
-        Returns node's path to root. Includes self.
+        Returns node's path to `node` (excludes `node`).
         """
         path = []
-        maybe_parent = node
+        maybe_parent = self.get_parent(node)
         while maybe_parent:
             path.append(maybe_parent)
             maybe_parent = self.get_parent(maybe_parent)

src/codemodder/scripts/generate_docs.py

@@ -251,6 +251,10 @@ class DocMetadata:
         importance="Medium",
         guidance_explained="This change is safe and will prevent runtime `ValueError`.",
     ),
+    "fix-missing-self-or-cls": DocMetadata(
+        importance="Medium",
+        guidance_explained="This change is safe and will prevent errors when calling on these instance or class methods..",
+    ),
 }
 
 METADATA = CORE_METADATA | {
@@ -305,6 +309,11 @@ class DocMetadata:
         guidance_explained=CORE_METADATA["jwt-decode-verify"].guidance_explained,
         need_sarif="Yes (Sonar)",
     ),
+    "fix-missing-self-or-cls-S5719": DocMetadata(
+        importance=CORE_METADATA["fix-missing-self-or-cls"].importance,
+        guidance_explained=CORE_METADATA["fix-missing-self-or-cls"].guidance_explained,
+        need_sarif="Yes (Sonar)",
+    ),
 }
 
 

src/core_codemods/__init__.py

@@ -17,6 +17,7 @@
 from .fix_deprecated_logging_warn import FixDeprecatedLoggingWarn
 from .fix_empty_sequence_comparison import FixEmptySequenceComparison
 from .fix_hasattr_call import TransformFixHasattrCall
+from .fix_missing_self_or_cls import FixMissingSelfOrCls
 from .fix_mutable_params import FixMutableParams
 from .flask_enable_csrf_protection import FlaskEnableCSRFProtection
 from .flask_json_response_type import FlaskJsonResponseType
@@ -48,6 +49,7 @@
 from .sonar.sonar_django_receiver_on_top import SonarDjangoReceiverOnTop
 from .sonar.sonar_exception_without_raise import SonarExceptionWithoutRaise
 from .sonar.sonar_fix_assert_tuple import SonarFixAssertTuple
+from .sonar.sonar_fix_missing_self_or_cls import SonarFixMissingSelfOrCls
 from .sonar.sonar_flask_json_response_type import SonarFlaskJsonResponseType
 from .sonar.sonar_jwt_decode_verify import SonarJwtDecodeVerify
 from .sonar.sonar_literal_or_new_object_identity import SonarLiteralOrNewObjectIdentity
@@ -127,6 +129,7 @@
         DjangoModelWithoutDunderStr,
         TransformFixHasattrCall,
         FixDataclassDefaults,
+        FixMissingSelfOrCls,
     ],
 )
 
@@ -142,5 +145,6 @@
         SonarFlaskJsonResponseType,
         SonarDjangoJsonResponseType,
         SonarJwtDecodeVerify,
+        SonarFixMissingSelfOrCls,
     ],
 )

src/core_codemods/docs/pixee_python_fix-missing-self-or-cls.md

@@ -0,0 +1,15 @@
+Python instance methods must be defined with `self` as the first argument. Likewise, class methods must have `cls` as the first argument. This codemod will add these arguments when the method/class method has no arguments defined.
+
+Our changes look something like this:
+
+```diff
+ class MyClass:
+-    def instance_method():
++    def instance_method(self):
+         print("instance_method")
+
+     @classmethod
+-    def class_method():
++    def class_method(cls):
+         print("class_method")
+```

src/core_codemods/fix_missing_self_or_cls.py

@@ -0,0 +1,87 @@
+import libcst as cst
+
+from codemodder.codemods.libcst_transformer import (
+    LibcstResultTransformer,
+    LibcstTransformerPipeline,
+)
+from codemodder.codemods.utils_mixin import NameAndAncestorResolutionMixin
+from core_codemods.api import Metadata, ReviewGuidance
+from core_codemods.api.core_codemod import CoreCodemod
+
+
+class FixMissingSelfOrClsTransformer(
+    LibcstResultTransformer, NameAndAncestorResolutionMixin
+):
+    change_description = "Add `self` or `cls` parameter to instance or class method."
+
+    def leave_FunctionDef(
+        self, original_node: cst.FunctionDef, updated_node: cst.FunctionDef
+    ) -> cst.FunctionDef:
+        # TODO: add filter by include or exclude that works for nodes
+        # that that have different start/end numbers.
+
+        if not self.find_immediate_class_def(original_node):
+            # If `original_node` is not inside a class, nothing to do.
+            return original_node
+
+        if self.find_immediate_function_def(original_node):
+            # If `original_node` is inside a class but also nested within a function/method
+            # We won't touch it.
+            return original_node
+
+        if original_node.decorators:
+            if self.is_staticmethod(original_node):
+                return updated_node
+            if self.is_classmethod(original_node):
+                if self.has_no_args(original_node):
+                    self.report_change(original_node)
+                    return updated_node.with_changes(
+                        params=updated_node.params.with_changes(
+                            params=[cst.Param(name=cst.Name("cls"))]
+                        )
+                    )
+        else:
+            if self.has_no_args(original_node):
+                self.report_change(original_node)
+                return updated_node.with_changes(
+                    params=updated_node.params.with_changes(
+                        params=[cst.Param(name=self._pick_arg_name(original_node))]
+                    )
+                )
+        return updated_node
+
+    def _pick_arg_name(self, node: cst.FunctionDef) -> cst.Name:
+        match node.name:
+            case cst.Name(value="__new__") | cst.Name(value="__init_subclass__"):
+                new_name = "cls"
+            case _:
+                new_name = "self"
+        return cst.Name(value=new_name)
+
+    def has_no_args(self, node: cst.FunctionDef) -> bool:
+        converted_star_arg = (
+            None
+            if node.params.star_arg is cst.MaybeSentinel.DEFAULT
+            else node.params.star_arg
+        )
+        return not any(
+            (
+                node.params.params,
+                converted_star_arg,
+                node.params.kwonly_params,
+                node.params.star_kwarg,
+                node.params.posonly_params,
+            )
+        )
+
+
+FixMissingSelfOrCls = CoreCodemod(
+    metadata=Metadata(
+        name="fix-missing-self-or-cls",
+        review_guidance=ReviewGuidance.MERGE_AFTER_CURSORY_REVIEW,
+        summary="Add Missing Positional Parameter for Instance and Class Methods",
+        references=[],
+    ),
+    transformer=LibcstTransformerPipeline(FixMissingSelfOrClsTransformer),
+    detector=None,
+)

src/core_codemods/sonar/sonar_fix_missing_self_or_cls.py

@@ -0,0 +1,12 @@
+from codemodder.codemods.base_codemod import Reference
+from codemodder.codemods.sonar import SonarCodemod
+from core_codemods.fix_missing_self_or_cls import FixMissingSelfOrCls
+
+SonarFixMissingSelfOrCls = SonarCodemod.from_core_codemod(
+    name="fix-missing-self-or-cls-S5719",
+    other=FixMissingSelfOrCls,
+    rules=["python:S5719"],
+    new_references=[
+        Reference(url="https://rules.sonarsource.com/python/RSPEC-5719/"),
+    ],
+)