Refactoring, better descriptions, and documentation

src/codemodder/codemods/utils.py

@@ -121,16 +121,14 @@ def __init__(self, context: CodemodContext) -> None:
         if dependencies:
             wrapper = self.context.wrapper
             if wrapper is None:
-                # pylint: disable-next=broad-exception-raised
-                raise Exception(
+                raise ValueError(
                     f"Attempting to instantiate {self.__class__.__name__} outside of "
                     + "an active transform. This means that metadata hasn't been "
                     + "calculated and we cannot successfully create this visitor."
                 )
             for dep in dependencies:
                 if dep not in wrapper._metadata:
-                    # pylint: disable-next=broad-exception-raised
-                    raise Exception(
+                    raise ValueError(
                         f"Attempting to access metadata {dep.__name__} that was not a "
                         + "declared dependency of parent transform! This means it is "
                         + "not possible to compute this value. Please ensure that all "

src/core_codemods/docs/pixee_python_file-resource-leak.md

@@ -1,4 +1,4 @@
-This codemod wraps assignments of `open` calls in a with statement. Without explicit closing, these resources will be "leaked", and won't be re-claimed until garbage collection. In situations where these resources are leaked rapidly (either through malicious repetitive action or unusually spiky usage), connection pool or file handle exhaustion will occur. These types of failures tend to be catastrophic, resulting in downtime and many times affect downstream applications.
+This codemod wraps assignments of `open` calls in a with statement. Without explicit closing, these resources will be "leaked" and won't be re-claimed until garbage collection. In situations where these resources are leaked rapidly (either through malicious repetitive action or unusually spiky usage), connection pool or file handle exhaustion will occur. These types of failures tend to be catastrophic, resulting in downtime and many times affect downstream applications.
 
 Our changes look something like this:
 

src/core_codemods/file_resource_leak.py

@@ -1,8 +1,8 @@
 from typing import Optional, Sequence
+from codemodder.utils.utils import extract_targets_of_assignment
 import libcst as cst
 from libcst import ensure_type, matchers
 from libcst.codemod import (
-    Codemod,
     CodemodContext,
     ContextAwareVisitor,
 )
@@ -14,34 +14,30 @@
 )
 from codemodder.change import Change
 from codemodder.codemods.base_codemod import (
-    BaseCodemod,
-    CodemodMetadata,
     ReviewGuidance,
 )
-from codemodder.codemods.base_visitor import UtilsMixin
+from codemodder.codemods.api import BaseCodemod
 from codemodder.codemods.utils import MetadataPreservingTransformer
 from codemodder.codemods.utils_mixin import AncestorPatternsMixin, NameResolutionMixin
 from codemodder.file_context import FileContext
 from functools import partial
 
 
-class FileResourceLeak(BaseCodemod, UtilsMixin, Codemod):
-    SUMMARY = "Automatically close resources"
-    METADATA = CodemodMetadata(
-        DESCRIPTION=SUMMARY,
-        NAME="file-resource-leak",
-        REVIEW_GUIDANCE=ReviewGuidance.MERGE_WITHOUT_REVIEW,
-        REFERENCES=[
-            {
-                "url": "https://cwe.mitre.org/data/definitions/772.html",
-                "description": "",
-            },
-            {
-                "url": "https://cwe.mitre.org/data/definitions/404.html",
-                "description": "",
-            },
-        ],
-    )
+class FileResourceLeak(BaseCodemod):
+    NAME = "file-resource-leak"
+    SUMMARY = "Automatically Close Resources"
+    REVIEW_GUIDANCE = ReviewGuidance.MERGE_WITHOUT_REVIEW
+    DESCRIPTION = SUMMARY
+    REFERENCES = [
+        {
+            "url": "https://cwe.mitre.org/data/definitions/772.html",
+            "description": "",
+        },
+        {
+            "url": "https://cwe.mitre.org/data/definitions/404.html",
+            "description": "",
+        },
+    ]
     CHANGE_DESCRIPTION = "Wrapped opened resource in a with statement."
 
     METADATA_DEPENDENCIES = (
@@ -59,9 +55,7 @@ def __init__(
         self.changed_nodes: dict[
             cst.CSTNode, cst.CSTNode | cst.RemovalSentinel | cst.FlattenSentinel
         ] = {}
-        BaseCodemod.__init__(self, file_context, *codemod_args)
-        UtilsMixin.__init__(self, [])
-        Codemod.__init__(self, context)
+        BaseCodemod.__init__(self, context, file_context, *codemod_args)
 
     def transform_module_impl(self, tree: cst.Module) -> cst.Module:
         fr = FindResources(self.context)
@@ -250,7 +244,7 @@ def _find_direct_name_assignment_targets(
         for node in (access.node for access in accesses):
             maybe_assigned = self.is_value_of_assignment(node)
             if maybe_assigned:
-                targets = self._extract_targets_of_assignment(maybe_assigned)
+                targets = extract_targets_of_assignment(maybe_assigned)
                 name_targets.extend(targets)
         return name_targets
 
@@ -286,7 +280,7 @@ def _find_transitive_assignment_targets(
         maybe_assigned = self.is_value_of_assignment(expr)
         if maybe_assigned:
             named_targets, other_targets = self._sieve_targets(
-                self._extract_targets_of_assignment(maybe_assigned)
+                extract_targets_of_assignment(maybe_assigned)
             )
             for n in named_targets:
                 n_named_targets, n_other_targets = self._find_name_assignment_targets(n)
@@ -295,22 +289,6 @@ def _find_transitive_assignment_targets(
             return named_targets, other_targets
         return ([], [])
 
-    def _extract_targets_of_assignment(
-        self, assignment: cst.AnnAssign | cst.Assign | cst.WithItem | cst.NamedExpr
-    ) -> list[cst.BaseExpression]:
-        match assignment:
-            case cst.AnnAssign():
-                if assignment.target:
-                    return [assignment.target]
-            case cst.Assign():
-                return [t.target for t in assignment.targets]
-            case cst.NamedExpr():
-                return [assignment.target]
-            case cst.WithItem():
-                if assignment.asname:
-                    return [assignment.asname.name]
-        return []
-
     # pylint: disable-next=too-many-arguments
     def _wrap_in_with_statement(
         self,