Restricts to use protected attributes, closes #272

Author: sobolevn

CHANGELOG.md

@@ -38,6 +38,7 @@ to the project during `#hactoberfest`. List of awesome people:
 - Forbids variable names with more than one consecutive underscore
 - Restricts the maximum number of base classes aka mixins
 - Forbids importing protected names
+- Forbids using protected methods and attributes
 - Forbids `yield` inside `__init__` method
 
 ### Bugfixes

tests/fixtures/noqa.py

@@ -8,6 +8,7 @@
 
 from .version import get_version  # noqa: Z300
 import sys as sys  # noqa: Z113
+from some import _protected  # noqa: Z440
 
 full_name = u'Nikita Sobolev'  # noqa: Z302
 phone_number = 555_123_999  # noqa:  Z303
@@ -29,9 +30,11 @@ def nested(): ...  # noqa: Z430
 value = 1  # noqa: Z110
 x = 2  # noqa: Z111
 __private = 3  # noqa: Z112
+consecutive__underscores = 4  # noqa: Z116
 __author__ = 'Nikita Sobolev'  # noqa: Z410
 
 nodes = [node for node in 'abc' if node != 'a' if node != 'b']  # noqa: Z307
+some._execute()  # noqa: Z441
 
 
 class BadClass:  # noqa: Z306
@@ -63,7 +66,7 @@ class Nested:  # noqa: Z306,Z431
 assert hex_number == hex_number  # noqa: Z312
 
 for symbol in 'abc':  # noqa: Z436
-    break
+    ...
 else:
     ...
 

tests/test_checker/test_noqa.py

@@ -25,6 +25,7 @@ def test_noqa_fixture_disabled(absolute_path):
         'Z111': 1,
         'Z112': 1,
         'Z113': 1,
+        'Z116': 1,
 
         'Z220': 1,
         'Z224': 1,
@@ -54,6 +55,8 @@ def test_noqa_fixture_disabled(absolute_path):
         'Z435': 1,
         'Z436': 1,
         'Z437': 1,
+        'Z440': 1,
+        'Z441': 1,
     }
 
     process = subprocess.Popen(

tests/test_violations/test_implementation.py

@@ -15,4 +15,4 @@ def test_visitor_returns_location():
 
 def test_checker_default_location():
     """Ensures that `BaseViolation` returns correct location."""
-    assert BaseViolation(None)._location() == (0, 0)
+    assert BaseViolation(None)._location() == (0, 0)  # noqa: Z441

tests/test_visitors/test_ast/test_attributes/test_protected_attributes.py

@@ -0,0 +1,110 @@
+# -*- coding: utf-8 -*-
+
+import pytest
+
+from wemake_python_styleguide.visitors.ast.attributes import (
+    ProtectedAttributeViolation,
+    WrongAttributeVisitor,
+)
+
+# Incorrect:
+
+protected_attribute_assigned = 'some._protected = 1'
+protected_attribute_accessed = 'print(some._protected)'
+protected_method_called = 'some._method()'
+protected_method_called_params = 'some._method(12, 33)'
+
+protected_container_attribute = """
+class Test(object):
+    def __init__(self):
+        self.container._print = 1
+"""
+
+protected_container_method = """
+class Test(object):
+    def __init__(self):
+        self.container._print()
+"""
+
+# Correct:
+
+protected_name_definition = '_protected = 1'
+protected_name_attr_definition = '_protected.some = 1'
+
+protected_self_attribute = """
+class Test(object):
+    def __init__(self):
+        self._print = 1
+"""
+
+protected_self_method = """
+class Test(object):
+    def __init__(self):
+        self._print()
+"""
+
+protected_cls_attribute = """
+class Test(object):
+    @classmethod
+    def method(cls):
+        cls._print = 'some'
+"""
+
+protected_cls_method = """
+class Test(object):
+    @classmethod
+    def method(cls):
+        cls._print()
+"""
+
+protected_attribute_definition = """
+class Test(object):
+    _protected = 1
+"""
+
+
+@pytest.mark.parametrize('code', [
+    protected_attribute_assigned,
+    protected_attribute_accessed,
+    protected_method_called,
+    protected_method_called_params,
+    protected_container_attribute,
+    protected_container_method,
+])
+def test_protected_attribute_is_restricted(
+    assert_errors,
+    parse_ast_tree,
+    code,
+    default_options,
+):
+    """Ensures that it is impossible to use protected attributes."""
+    tree = parse_ast_tree(code)
+
+    visitor = WrongAttributeVisitor(default_options, tree=tree)
+    visitor.run()
+
+    assert_errors(visitor, [ProtectedAttributeViolation])
+
+
+@pytest.mark.parametrize('code', [
+    protected_name_definition,
+    protected_name_attr_definition,
+    protected_self_attribute,
+    protected_self_method,
+    protected_cls_attribute,
+    protected_cls_method,
+    protected_attribute_definition,
+])
+def test_protected_attribute_is_allowed(
+    assert_errors,
+    parse_ast_tree,
+    code,
+    default_options,
+):
+    """Ensures that it is possible to use protected attributes."""
+    tree = parse_ast_tree(code)
+
+    visitor = WrongAttributeVisitor(default_options, tree=tree)
+    visitor.run()
+
+    assert_errors(visitor, [])

tests/test_visitors/test_ast/test_strings/test_formatted_string.py renamed to tests/test_visitors/test_ast/test_builtins/test_formatted_string.py

@@ -5,11 +5,14 @@
 from wemake_python_styleguide.violations.consistency import (
     FormattedStringViolation,
 )
-from wemake_python_styleguide.visitors.ast.strings import WrongStringVisitor
+from wemake_python_styleguide.visitors.ast.builtins import WrongStringVisitor
 
 regular_string = "'some value'"
+binary_string = "b'binary'"
+unicode_string = "u'unicode'"
 string_variable = "some = '123'"
 formated_string = "'x + y = {0}'.format(2)"
+procent_format = "'x = %d' % 1"
 key_formated_string = "'x + y = {res}'.format(res=2)"
 variable_format = """
 some = 'x = {0}'
@@ -22,8 +25,11 @@
 
 @pytest.mark.parametrize('code', [
     regular_string,
+    binary_string,
+    unicode_string,
     string_variable,
     formated_string,
+    procent_format,
     key_formated_string,
     variable_format,
 ])

tests/test_visitors/test_ast/test_numbers/test_magic_numbers.py renamed to tests/test_visitors/test_ast/test_builtins/test_magic_numbers.py

@@ -2,13 +2,11 @@
 
 import pytest
 
+from wemake_python_styleguide.constants import MAGIC_NUMBERS_WHITELIST
 from wemake_python_styleguide.violations.best_practices import (
     MagicNumberViolation,
 )
-from wemake_python_styleguide.visitors.ast.numbers import (
-    MAGIC_NUMBERS_WHITELIST,
-    MagicNumberVisitor,
-)
+from wemake_python_styleguide.visitors.ast.builtins import MagicNumberVisitor
 
 # Correct usages:
 

tests/test_visitors/test_ast/test_classes/test_yield_inside_init.py

@@ -19,6 +19,18 @@ def __init__(self, *args, **kwargs):
         yield self
 """
 
+regular_method_with_yield = """
+class ModuleMembersVisitor(object):
+    def method(self, *args, **kwargs):
+        yield self
+"""
+
+iter_with_yield = """
+class ModuleMembersVisitor(object):
+    def __iter__(self, *args, **kwargs):
+        yield self
+"""
+
 async_init_without_yield = """
 class ModuleMembersVisitor(object):
     async def __init__(self, *args, **kwargs):
@@ -54,6 +66,8 @@ def test_init_generator(
 @pytest.mark.parametrize('code', [
     init_without_yield,
     async_init_without_yield,
+    regular_method_with_yield,
+    iter_with_yield,
 ])
 def test_init_regular(
     assert_errors,

tests/test_visitors/test_ast/test_complexity/test_jones/test_line_complexity.py

@@ -111,9 +111,9 @@ def test_same_complexity(parse_ast_tree, default_options):
     simple_visitor.run()
     typed_visitor.run()
 
-    assert len(simple_visitor._lines) == 1
-    assert len(simple_visitor._lines[1]) == 3
-    assert len(simple_visitor._lines[1]) == len(typed_visitor._lines[1])
+    assert len(simple_visitor._lines) == 1  # noqa: Z441
+    assert len(simple_visitor._lines[1]) == 3  # noqa: Z441
+    assert len(typed_visitor._lines[1]) == 3  # noqa: Z441
 
 
 @pytest.mark.parametrize('code, complexity', [
@@ -127,8 +127,8 @@ def test_exact_complexity(parse_ast_tree, default_options, code, complexity):
     visitor = JonesComplexityVisitor(default_options, tree=tree)
     visitor.run()
 
-    assert len(visitor._lines) == 1
-    assert len(visitor._lines[1]) == complexity
+    assert len(visitor._lines) == 1  # noqa: Z441
+    assert len(visitor._lines[1]) == complexity  # noqa: Z441
 
 
 @pytest.mark.parametrize('code, number_of_lines', [
@@ -147,4 +147,4 @@ def test_that_some_nodes_are_ignored(
     visitor = JonesComplexityVisitor(default_options, tree=tree)
     visitor.run()
 
-    assert len(visitor._lines) == number_of_lines
+    assert len(visitor._lines) == number_of_lines  # noqa: Z441

tests/test_visitors/test_ast/test_imports/test_protected_import.py

@@ -2,7 +2,9 @@
 
 import pytest
 
-from wemake_python_styleguide.violations.naming import ProtectedModuleViolation
+from wemake_python_styleguide.violations.best_practices import (
+    ProtectedModuleViolation,
+)
 from wemake_python_styleguide.visitors.ast.imports import WrongImportVisitor
 
 import_public = 'import public'
@@ -19,11 +21,18 @@
     import_from_public,
     import_from_public_path,
 ])
-def test_correct_import(assert_errors, parse_ast_tree, code, default_options):
+def test_correct_import(
+    assert_errors,
+    parse_ast_tree,
+    code,
+    default_options,
+):
     """Testing that correct imports are allowed."""
     tree = parse_ast_tree(code)
+
     visitor = WrongImportVisitor(default_options, tree=tree)
     visitor.run()
+
     assert_errors(visitor, [])
 
 
@@ -32,9 +41,16 @@ def test_correct_import(assert_errors, parse_ast_tree, code, default_options):
     import_from_protected,
     import_from_protected_path,
 ])
-def test_incorrect_import(assert_errors, parse_ast_tree, code, default_options):
+def test_incorrect_import(
+    assert_errors,
+    parse_ast_tree,
+    code,
+    default_options,
+):
     """Testing that imports from protected modules are restricted."""
     tree = parse_ast_tree(code)
+
     visitor = WrongImportVisitor(default_options, tree=tree)
     visitor.run()
+
     assert_errors(visitor, [ProtectedModuleViolation])