Experimental: Unify NamingSchemes.

CONTRIBUTORS.txt

@@ -392,6 +392,8 @@ contributors:
 
 * Jochen Preusche (iilei): contributor
 
+* Buck Evan (bukzor, Google LLC): contributor
+
 * Ram Rachum (cool-RR)
 
 * Pieter Engelbrecht

ChangeLog

@@ -10,6 +10,14 @@ Pylint's ChangeLog
 
   Close #3834
 
+* The `invalid-name` checker has been re-worked for increased consistency. Some
+  names that previously passed unnoticed will be flagged. You may solve these
+  new issues three (or more) ways:
+
+   1. increase the length of names to be more descriptive (recommended)
+   2. add strange-but-useful names to the good-names configuration
+   3. override the default regexen, via pylintrc (not recommended)
+
 
 What's New in Pylint 2.6.1?
 ===========================

pylint/checkers/base.py

@@ -62,7 +62,6 @@
 import itertools
 import re
 import sys
-from typing import Pattern
 
 import astroid
 import astroid.bases
@@ -81,83 +80,69 @@
 
 
 class NamingStyle:
-    # It may seem counterintuitive that single naming style
-    # has multiple "accepted" forms of regular expressions,
-    # but we need to special-case stuff like dunder names
-    # in method names.
-    CLASS_NAME_RGX = None  # type: Pattern[str]
-    MOD_NAME_RGX = None  # type: Pattern[str]
-    CONST_NAME_RGX = None  # type: Pattern[str]
-    COMP_VAR_RGX = None  # type: Pattern[str]
-    DEFAULT_NAME_RGX = None  # type: Pattern[str]
-    CLASS_ATTRIBUTE_RGX = None  # type: Pattern[str]
-
-    @classmethod
-    def get_regex(cls, name_type):
-        return {
-            "module": cls.MOD_NAME_RGX,
-            "const": cls.CONST_NAME_RGX,
-            "class": cls.CLASS_NAME_RGX,
-            "function": cls.DEFAULT_NAME_RGX,
-            "method": cls.DEFAULT_NAME_RGX,
-            "attr": cls.DEFAULT_NAME_RGX,
-            "argument": cls.DEFAULT_NAME_RGX,
-            "variable": cls.DEFAULT_NAME_RGX,
-            "class_attribute": cls.CLASS_ATTRIBUTE_RGX,
-            "inlinevar": cls.COMP_VAR_RGX,
-        }[name_type]
-
+    name_template = r"[^\W\d_%s][^\W%s]%s"
+
+    def __init__(self, head_exclude: str, tail_exclude: str, min_length: int):
+        self.head_exclude = head_exclude
+        self.tail_exclude = tail_exclude
+        self.min_length = min_length
+
+        if min_length == 1:
+            tail_length = "*"
+        elif min_length == 2:
+            tail_length = "+"
+        elif min_length > 2:
+            tail_length = "{%i,}" % (min_length - 1)
+        else:
+            raise AssertionError(tail_length)
 
-class SnakeCaseStyle(NamingStyle):
-    """Regex rules for snake_case naming style."""
+        word = self.name_template % (head_exclude, tail_exclude, tail_length)
+        snake_word = self.name_template % ("A-Z", "A-Z", tail_length)
 
-    CLASS_NAME_RGX = re.compile(r"[^\W\dA-Z][^\WA-Z]+$")
-    MOD_NAME_RGX = re.compile(r"[^\W\dA-Z][^\WA-Z]*$")
-    CONST_NAME_RGX = re.compile(r"([^\W\dA-Z][^\WA-Z]*|__.*__)$")
-    COMP_VAR_RGX = re.compile(r"[^\W\dA-Z][^\WA-Z]*$")
-    DEFAULT_NAME_RGX = re.compile(
-        r"([^\W\dA-Z][^\WA-Z]{2,}|_[^\WA-Z]*|__[^\WA-Z\d_][^\WA-Z]+__)$"
-    )
-    CLASS_ATTRIBUTE_RGX = re.compile(r"([^\W\dA-Z][^\WA-Z]{2,}|__.*__)$")
+        name = r"_{0,2}%s" % word
+        dunder = r"__%s__" % snake_word
 
+        self.NAME_RGX = re.compile("^(%s)$" % name)
+        self.ATTR_RGX = re.compile("^(%s|%s)$" % (name, dunder))
 
-class CamelCaseStyle(NamingStyle):
-    """Regex rules for camelCase naming style."""
-
-    CLASS_NAME_RGX = re.compile(r"[^\W\dA-Z][^\W_]+$")
-    MOD_NAME_RGX = re.compile(r"[^\W\dA-Z][^\W_]*$")
-    CONST_NAME_RGX = re.compile(r"([^\W\dA-Z][^\W_]*|__.*__)$")
-    COMP_VAR_RGX = re.compile(r"[^\W\dA-Z][^\W_]*$")
-    DEFAULT_NAME_RGX = re.compile(r"([^\W\dA-Z][^\W_]{2,}|__[^\W\dA-Z_]\w+__)$")
-    CLASS_ATTRIBUTE_RGX = re.compile(r"([^\W\dA-Z][^\W_]{2,}|__.*__)$")
+    def get_regex(self, name_type):
+        # It may seem counterintuitive that single naming style
+        # has multiple "accepted" forms of regular expressions,
+        # but we need to special-case stuff like dunder names
+        # in method names.
+        return {
+            "module": self.NAME_RGX,
+            "const": self.ATTR_RGX,
+            "class": self.NAME_RGX,
+            "function": self.ATTR_RGX,
+            "method": self.ATTR_RGX,
+            "attr": self.ATTR_RGX,
+            "argument": self.ATTR_RGX,
+            "variable": self.ATTR_RGX,
+            "class_attribute": self.ATTR_RGX,
+            "inlinevar": self.NAME_RGX,
+        }[name_type]
 
 
-class PascalCaseStyle(NamingStyle):
-    """Regex rules for PascalCase naming style."""
+# Regex rules for snake_case naming style.
+SnakeCaseStyle = NamingStyle("A-Z", "A-Z", 3)
 
-    CLASS_NAME_RGX = re.compile(r"[^\W\da-z][^\W_]+$")
-    MOD_NAME_RGX = re.compile(r"[^\W\da-z][^\W_]+$")
-    CONST_NAME_RGX = re.compile(r"([^\W\da-z][^\W_]*|__.*__)$")
-    COMP_VAR_RGX = re.compile(r"[^\W\da-z][^\W_]+$")
-    DEFAULT_NAME_RGX = re.compile(r"([^\W\da-z][^\W_]{2,}|__[^\W\dA-Z_]\w+__)$")
-    CLASS_ATTRIBUTE_RGX = re.compile(r"[^\W\da-z][^\W_]{2,}$")
+# Regex rules for camelCase naming style.
+CamelCaseStyle = NamingStyle("A-Z", "_", 3)
 
+# Regex rules for PascalCase naming style.
+PascalCaseStyle = NamingStyle("a-z", "_", 3)
 
-class UpperCaseStyle(NamingStyle):
-    """Regex rules for UPPER_CASE naming style."""
+# Regex rules for UPPER_CASE naming style.
+UpperCaseStyle = NamingStyle("a-z", "a-z", 3)
 
-    CLASS_NAME_RGX = re.compile(r"[^\W\da-z][^\Wa-z]+$")
-    MOD_NAME_RGX = re.compile(r"[^\W\da-z][^\Wa-z]+$")
-    CONST_NAME_RGX = re.compile(r"([^\W\da-z][^\Wa-z]*|__.*__)$")
-    COMP_VAR_RGX = re.compile(r"[^\W\da-z][^\Wa-z]+$")
-    DEFAULT_NAME_RGX = re.compile(r"([^\W\da-z][^\Wa-z]{2,}|__[^\W\dA-Z_]\w+__)$")
-    CLASS_ATTRIBUTE_RGX = re.compile(r"[^\W\da-z][^\Wa-z]{2,}$")
+AnyStyle = NamingStyle("", "", 1)
 
 
-class AnyStyle(NamingStyle):
-    @classmethod
-    def get_regex(cls, name_type):
-        return re.compile(".*")
+class NoStyle(NamingStyle):
+    @staticmethod
+    def get_regex(name_type):
+        return re.compile(".+")
 
 
 NAMING_STYLES = {
@@ -166,6 +151,7 @@ def get_regex(cls, name_type):
     "PascalCase": PascalCaseStyle,
     "UPPER_CASE": UpperCaseStyle,
     "any": AnyStyle,
+    "none": NoStyle,
 }
 
 # do not require a doc string on private/system methods

pytest.ini

@@ -1,5 +1,5 @@
 [pytest]
 python_files=*test_*.py
-addopts=-m "not acceptance"
+addopts=-m "not acceptance" --tb=short
 markers =
    acceptance

tests/conftest.py

@@ -8,6 +8,14 @@
 from pylint.lint import PyLinter
 from pylint.testutils import MinimalTestReporter
 
+TOP = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+PYLINTRC = os.path.join(TOP, "pylintrc")
+
+
+@pytest.fixture(autouse=True)
+def pylintrc():
+    os.environ["PYLINTRC"] = PYLINTRC
+
 
 @pytest.fixture
 def linter(checker, register, enable, disable, reporter):
@@ -24,7 +32,7 @@ def linter(checker, register, enable, disable, reporter):
     if enable:
         for msg in enable:
             _linter.enable(msg)
-    os.environ.pop("PYLINTRC", None)
+    os.environ["PYLINTRC"] = PYLINTRC
     return _linter
 
 

tests/extensions/data/compare_to_zero.py

@@ -1,4 +1,4 @@
-# pylint: disable=literal-comparison,missing-docstring,misplaced-comparison-constant
+# pylint: disable=literal-comparison,missing-docstring,misplaced-comparison-constant,invalid-name
 
 X = 123
 Y = len('test')

tests/extensions/data/empty_string_comparison.py

@@ -1,4 +1,4 @@
-# pylint: disable=literal-comparison,missing-docstring
+# pylint: disable=literal-comparison,missing-docstring,invalid-name
 
 X = ''
 Y = 'test'

tests/functional/a/arguments_differ.rc

@@ -0,0 +1,2 @@
+[basics]
+good-names=___private3

tests/functional/l/line_too_long.py

@@ -5,7 +5,7 @@
 """ that one is too long tooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo loooooong"""
 
 # The next line is exactly 80 characters long.
-A = "--------------------------------------------------------------------------"
+_ = "--------------------------------------------------------------------------"
 
 # Do not trigger the line-too-long warning if the only token that makes the
 # line longer than 80 characters is a trailing pylint disable.

tests/functional/m/method_hidden.py

@@ -28,12 +28,12 @@ class CustomProperty:
     def __init__(self, _):
         pass
 
-    def __get__(self, obj, __):
+    def __get__(self, obj, _):
         if not obj:
             return self
         return 5
 
-    def __set__(self, _, __):
+    def __set__(self, _key, _val):
         pass
 
 class Ddef:

tests/functional/n/namePresetCamelCase.txt

@@ -1,3 +1,3 @@
-invalid-name:3::"Constant name ""SOME_CONSTANT"" doesn't conform to camelCase naming style ('([^\\W\\dA-Z][^\\W_]*|__.*__)$' pattern)"
-invalid-name:10:MyClass:"Class name ""MyClass"" doesn't conform to camelCase naming style ('[^\\W\\dA-Z][^\\W_]+$' pattern)"
-invalid-name:22:say_hello:"Function name ""say_hello"" doesn't conform to camelCase naming style ('([^\\W\\dA-Z][^\\W_]{2,}|__[^\\W\\dA-Z_]\\w+__)$' pattern)"
+invalid-name:3::"Constant name ""SOME_CONSTANT"" doesn't conform to camelCase naming style ('^(_{0,2}[^\\W\\d_A-Z][^\\W_]{2,}|__[^\\W\\d_A-Z][^\\WA-Z]{2,}__)$' pattern)"
+invalid-name:10:MyClass:"Class name ""MyClass"" doesn't conform to camelCase naming style ('^(_{0,2}[^\\W\\d_A-Z][^\\W_]{2,})$' pattern)"
+invalid-name:22:say_hello:"Function name ""say_hello"" doesn't conform to camelCase naming style ('^(_{0,2}[^\\W\\d_A-Z][^\\W_]{2,}|__[^\\W\\d_A-Z][^\\WA-Z]{2,}__)$' pattern)"

tests/functional/n/name_good_bad_names_regex.txt

@@ -1,3 +1,3 @@
 blacklisted-name:5::"Black listed name ""explicit_bad_some_constant"""
-invalid-name:7::"Constant name ""snake_case_bad_SOME_CONSTANT"" doesn't conform to snake_case naming style ('([^\\W\\dA-Z][^\\WA-Z]*|__.*__)$' pattern)"
+invalid-name:7::"Constant name ""snake_case_bad_SOME_CONSTANT"" doesn't conform to snake_case naming style ('^(_{0,2}[^\\W\\d_A-Z][^\\WA-Z]{2,}|__[^\\W\\d_A-Z][^\\WA-Z]{2,}__)$' pattern)"
 blacklisted-name:19:blacklisted_2_snake_case:"Black listed name ""blacklisted_2_snake_case"""

tests/functional/n/name_preset_snake_case.txt

@@ -1,3 +1,3 @@
-invalid-name:3::"Constant name ""SOME_CONSTANT"" doesn't conform to snake_case naming style ('([^\\W\\dA-Z][^\\WA-Z]*|__.*__)$' pattern)"
-invalid-name:10:MyClass:"Class name ""MyClass"" doesn't conform to snake_case naming style ('[^\\W\\dA-Z][^\\WA-Z]+$' pattern)"
-invalid-name:22:sayHello:"Function name ""sayHello"" doesn't conform to snake_case naming style ('([^\\W\\dA-Z][^\\WA-Z]{2,}|_[^\\WA-Z]*|__[^\\WA-Z\\d_][^\\WA-Z]+__)$' pattern)"
+invalid-name:3::"Constant name ""SOME_CONSTANT"" doesn't conform to snake_case naming style ('^(_{0,2}[^\\W\\d_A-Z][^\\WA-Z]{2,}|__[^\\W\\d_A-Z][^\\WA-Z]{2,}__)$' pattern)"
+invalid-name:10:MyClass:"Class name ""MyClass"" doesn't conform to snake_case naming style ('^(_{0,2}[^\\W\\d_A-Z][^\\WA-Z]{2,})$' pattern)"
+invalid-name:22:sayHello:"Function name ""sayHello"" doesn't conform to snake_case naming style ('^(_{0,2}[^\\W\\d_A-Z][^\\WA-Z]{2,}|__[^\\W\\d_A-Z][^\\WA-Z]{2,}__)$' pattern)"

tests/functional/r/regression_2443_duplicate_bases.rc

@@ -1,2 +1,4 @@
 [testoptions]
 min_pyver=3.6
+[basics]
+good-names=IN

tests/functional/u/undefined_variable.rc

@@ -0,0 +1,2 @@
+[basics]
+good-names=i,j,k,ex,Run,_,_dt

tests/functional/u/unnecessary_pass.py

@@ -1,9 +1,9 @@
 # pylint: disable=missing-docstring, too-few-public-methods
 
 try:
-    A = 2
+    _ = 2
 except ValueError:
-    A = 24
+    _ = 24
     pass # [unnecessary-pass]
 
 def docstring_only():

tests/functional/w/wrong_import_position11.py

@@ -1,4 +1,4 @@
 """Checks import position rule"""
 # pylint: disable=unused-import,pointless-string-statement
-A = 1
+_ = 1
 import os  # [wrong-import-position]

tests/functional/w/wrong_import_position13.py

@@ -1,4 +1,4 @@
 """Checks import position rule"""
 # pylint: disable=unused-import,no-name-in-module
-A = 1
+_ = 1
 from sys import x  # [wrong-import-position]

tests/input/func_excess_escapes.py

@@ -4,7 +4,7 @@
 __revision__ = '$Id$'
 
 # Bad escape sequences, which probably don't do what you expect.
-A = "\[\]\\"
+_ = "\[\]\\"
 assert '\/' == '\\/'
 ESCAPE_BACKSLASH = '\`'
 

tests/input/func_typecheck_callfunc_assigment.py

@@ -15,22 +15,22 @@ def func_no_return():
     """function without return"""
     print('dougloup')
 
-A = func_no_return()
+_ = func_no_return()
 
 
 def func_return_none():
     """function returning none"""
     print('dougloup')
     return None
 
-A = func_return_none()
+_ = func_return_none()
 
 
 def func_implicit_return_none():
     """Function returning None from bare return statement."""
     return
 
-A = func_implicit_return_none()
+_ = func_implicit_return_none()
 
 
 def func_return_none_and_smth():
@@ -40,13 +40,13 @@ def func_return_none_and_smth():
         return None
     return 3
 
-A = func_return_none_and_smth()
+_ = func_return_none_and_smth()
 
 def generator():
     """no problemo"""
     yield 2
 
-A = generator()
+_ = generator()
 
 class Abstract(object):
     """bla bla"""

tests/input/func_w0801.py

@@ -1,6 +1,7 @@
 """test code similarities
-by defaut docstring are not considered
+by default docstring are not considered
 """
+# pylint: disable=invalid-name
 __revision__ = 'id'
 A = 2
 B = 3

tests/input/w0801_same.py

@@ -1,6 +1,7 @@
 """test code similarities
-by defaut docstring are not considered
+by default docstring are not considered
 """
+# pylint: disable=invalid-name
 __revision__ = 'id'
 A = 2
 B = 3

tests/messages/func_w0801.txt

@@ -1,6 +1,6 @@
 R:  1: Similar lines in 2 files
-==input.func_w0801:3
-==input.w0801_same:3
+==input.func_w0801:4
+==input.w0801_same:4
 __revision__ = 'id'
 A = 2
 B = 3