Stricter interface for Lint._parse

Author: SamWilsn

src/ethereum_spec_tools/lint/__init__.py

@@ -12,7 +12,8 @@
 from abc import ABCMeta, abstractmethod
 from dataclasses import dataclass
 from itertools import zip_longest
-from typing import Generator, List, Optional, Sequence, Tuple
+from pathlib import Path
+from typing import Generator, List, Optional, Sequence, Tuple, TypeVar
 
 from ..forks import Hardfork
 
@@ -78,6 +79,9 @@ class Diagnostic:
     message: str
 
 
+V = TypeVar("V", bound=ast.NodeVisitor)
+
+
 class Lint(metaclass=ABCMeta):
     """
     A single check which may be performed against the specifications.
@@ -98,15 +102,13 @@ def lint(
             The particular hardfork to lint.
         """
 
-    def _parse(
-        self, source: str, visitor: ast.NodeVisitor, attr: str
-    ) -> Sequence[str]:
+    def _parse(self, source: str, visitor: V) -> V:
         """
-        Walks the source string and extracts a sequence of identifiers.
+        Walks the source string.
         """
         parsed = ast.parse(source)
         visitor.visit(parsed)
-        return getattr(visitor, attr)
+        return visitor
 
 
 class Linter:

src/ethereum_spec_tools/lint/lints/glacier_forks_hygiene.py

@@ -95,13 +95,11 @@ def lint(
                 )
                 continue
 
-            current_node = self._parse(all_current[file], _Visitor(), "items")
-            previous_node = self._parse(
-                all_previous[file], _Visitor(), "items"
-            )
+            current_node = self._parse(all_current[file], _Visitor()).items
+            previous_node = self._parse(all_previous[file], _Visitor()).items
 
             diagnostics += self.compare(
-                fork_name, file, current_node, previous_node  # type: ignore
+                fork_name, file, current_node, previous_node
             )
 
         return diagnostics

src/ethereum_spec_tools/lint/lints/import_hygiene.py

@@ -55,7 +55,7 @@ def check_import(
             else tuple()
         )
 
-        current_imports = self._parse(source, _Visitor(), "item_imports")
+        current_imports = self._parse(source, _Visitor()).item_imports
 
         for item in current_imports:
             if item is None:

src/ethereum_spec_tools/lint/lints/patch_hygiene.py

@@ -50,11 +50,11 @@ def compare(
             # Entire file is new, so nothing to compare!
             return []
 
-        current_nodes = self._parse(current_source, _Visitor(), "items")
+        current_nodes = self._parse(current_source, _Visitor()).items
         previous_nodes = {
             item: idx
             for (idx, item) in enumerate(
-                self._parse(previous_source, _Visitor(), "items")
+                self._parse(previous_source, _Visitor()).items
             )
         }