Merge pull request #121 from asfaltboy/ps/module-name-shadowing

feat: module name shadowing

CHANGES.rst

@@ -6,7 +6,8 @@ Changelog
 2.2.1 (unreleased)
 ------------------
 
-- Nothing changed yet.
+- Add rule for builtin module name shadowing (`A005`).
+  [asfaltboy]
 
 
 2.2.0 (2023-11-03)

README.rst

@@ -101,6 +101,9 @@ A003:
 A004:
   An import statement is shadowing a Python builtin.
 
+A005:
+  A module is shadowing a Python builtin module (e.g: `logging` or `socket`)
+
 License
 -------
 GPL 2.0

flake8_builtins.py

@@ -1,8 +1,10 @@
 from flake8 import utils as stdin_utils
+from pathlib import Path
 
 import ast
 import builtins
 import inspect
+import sys
 
 
 class BuiltinsChecker:
@@ -12,6 +14,7 @@ class BuiltinsChecker:
     argument_msg = 'A002 argument "{0}" is shadowing a Python builtin'
     class_attribute_msg = 'A003 class attribute "{0}" is shadowing a Python builtin'
     import_msg = 'A004 import statement "{0}" is shadowing a Python builtin'
+    module_name_msg = 'A005 the module is shadowing a Python builtin module "{0}"'
 
     names = []
     ignore_list = {
@@ -20,6 +23,7 @@ class BuiltinsChecker:
         'credits',
         '_',
     }
+    ignored_module_names = set()
 
     def __init__(self, tree, filename):
         self.tree = tree
@@ -34,6 +38,13 @@ def add_options(cls, option_manager):
             comma_separated_list=True,
             help='A comma separated list of builtins to skip checking',
         )
+        option_manager.add_option(
+            '--builtins-allowed-modules',
+            metavar='builtins',
+            parse_from_config=True,
+            comma_separated_list=True,
+            help='A comma separated list of builtin module names to allow',
+        )
 
     @classmethod
     def parse_options(cls, options):
@@ -47,12 +58,26 @@ def parse_options(cls, options):
         if flake8_builtins:
             cls.names.update(flake8_builtins)
 
+        if options.builtins_allowed_modules is not None:
+            cls.ignored_module_names.update(options.builtins_allowed_modules)
+
+        if hasattr(sys, 'stdlib_module_names'):
+            # stdlib_module_names is only available in Python 3.10+
+            known_module_names = sys.stdlib_module_names
+            cls.module_names = {
+                m for m in known_module_names if m not in cls.ignored_module_names
+            }
+        else:
+            cls.module_names = set()
+
     def run(self):
         tree = self.tree
 
         if self.filename == 'stdin':
             lines = stdin_utils.stdin_get_value()
             tree = ast.parse(lines)
+        else:
+            yield from self.check_module_name(self.filename)
 
         for statement in ast.walk(tree):
             for child in ast.iter_child_nodes(statement):
@@ -234,13 +259,26 @@ def check_class(self, statement):
         if statement.name in self.names:
             yield self.error(statement, variable=statement.name)
 
-    def error(self, statement, variable, message=None):
+    def error(self, statement=None, variable=None, message=None):
         if not message:
             message = self.assign_msg
 
+        # lineno and col_offset must be integers
         return (
-            statement.lineno,
-            statement.col_offset,
+            statement.lineno if statement else 0,
+            statement.col_offset if statement else 0,
             message.format(variable),
             type(self),
         )
+
+    def check_module_name(self, filename: str):
+        if not self.module_names:
+            return
+        path = Path(filename)
+        module_name = path.name.removesuffix('.py')
+        if module_name in self.module_names:
+            yield self.error(
+                None,
+                module_name,
+                message=self.module_name_msg,
+            )

run_tests.py

@@ -10,15 +10,25 @@
 class FakeOptions:
     builtins_ignorelist = []
     builtins = None
+    builtins_allowed_modules = None
 
-    def __init__(self, ignore_list='', builtins=None):
+    def __init__(self, ignore_list='', builtins=None, builtins_allowed_modules=None):
         if ignore_list:
             self.builtins_ignorelist = ignore_list
         if builtins:
             self.builtins = builtins
-
-
-def check_code(source, expected_codes=None, ignore_list=None, builtins=None):
+        if builtins_allowed_modules:
+            self.builtins_allowed_modules = builtins_allowed_modules
+
+
+def check_code(
+    source,
+    expected_codes=None,
+    ignore_list=None,
+    builtins=None,
+    builtins_allowed_modules=None,
+    filename='/home/script.py',
+):
     """Check if the given source code generates the given flake8 errors
 
     If `expected_codes` is a string is converted to a list,
@@ -37,8 +47,14 @@ def check_code(source, expected_codes=None, ignore_list=None, builtins=None):
     if ignore_list is None:
         ignore_list = []
     tree = ast.parse(textwrap.dedent(source))
-    checker = BuiltinsChecker(tree, '/home/script.py')
-    checker.parse_options(FakeOptions(ignore_list=ignore_list, builtins=builtins))
+    checker = BuiltinsChecker(tree, filename)
+    checker.parse_options(
+        FakeOptions(
+            ignore_list=ignore_list,
+            builtins=builtins,
+            builtins_allowed_modules=builtins_allowed_modules,
+        )
+    )
     return_statements = list(checker.run())
 
     assert len(return_statements) == len(expected_codes)
@@ -463,12 +479,36 @@ async def bla():
 def test_stdin(stdin_get_value):
     source = 'max = 4'
     stdin_get_value.return_value = source
-    checker = BuiltinsChecker('', 'stdin')
-    checker.parse_options(FakeOptions())
-    ret = list(checker.run())
-    assert len(ret) == 1
+    check_code('', expected_codes='A001', filename='stdin')
 
 
 def test_tuple_unpacking():
     source = 'a, *(b, c) = 1, 2, 3'
     check_code(source)
+
+
+@pytest.mark.skipif(
+    sys.version_info < (3, 10),
+    reason='Skip A005, module testing is only supported in Python 3.10 and above',
+)
+def test_module_name():
+    source = ''
+    check_code(source, expected_codes='A005', filename='./temp/logging.py')
+
+
+@pytest.mark.skipif(
+    sys.version_info < (3, 10),
+    reason='Skip A005, module testing is only supported in Python 3.10 and above',
+)
+def test_module_name_ignore_module():
+    source = ''
+    check_code(
+        source,
+        filename='./temp/logging.py',
+        builtins_allowed_modules=['logging'],
+    )
+
+
+def test_module_name_not_builtin():
+    source = ''
+    check_code(source, filename='log_config')