Ignore leading underscores in private/protected methods for camelCase style (#10228)

Author: alexprabhat99

doc/whatsnew/fragments/10189.bugfix

@@ -0,0 +1,3 @@
+Fixed raising invalid-name when using camelCase for private methods with two leading underscores.
+
+Closes #10189

pylint/checkers/base/name_checker/naming_style.py

@@ -64,7 +64,7 @@ class CamelCaseStyle(NamingStyle):
     MOD_NAME_RGX = re.compile(r"[^\W\dA-Z][^\W_]*$")
     CONST_NAME_RGX = re.compile(r"([^\W\dA-Z][^\W_]*|__.*__)$")
     COMP_VAR_RGX = MOD_NAME_RGX
-    DEFAULT_NAME_RGX = re.compile(r"([^\W\dA-Z][^\W_]*|__[^\W\dA-Z_]\w+__)$")
+    DEFAULT_NAME_RGX = re.compile(r"(?:__)?([^\W\dA-Z][^\W_]*|__[^\W\dA-Z_]\w+__)$")
     CLASS_ATTRIBUTE_RGX = re.compile(r"([^\W\dA-Z][^\W_]*|__.*__)$")
 
 

tests/functional/n/namePresetCamelCase.py

@@ -1,4 +1,4 @@
-# pylint: disable=missing-docstring,too-few-public-methods
+# pylint: disable=missing-docstring,too-few-public-methods,unused-private-member
 __version__ = "1.0"
 SOME_CONSTANT = 42  # [invalid-name]
 
@@ -18,6 +18,11 @@ def myPublicX(self):
     def __eq__(self, other):
         return isinstance(other, MyClass) and self.myPublicX == other.myPublicX
 
+    def __privateMethod(self):
+        pass
+
+    def _protectedMethod(self):
+        pass
 
 def say_hello():  # [invalid-name]
     pass

tests/functional/n/namePresetCamelCase.txt

@@ -1,3 +1,3 @@
-invalid-name:3:0:3:13::"Constant name ""SOME_CONSTANT"" doesn't conform to camelCase naming style ('([^\\W\\dA-Z][^\\W_]*|__.*__)$' pattern)":HIGH
-invalid-name:10:0:10:13:MyClass:"Class name ""MyClass"" doesn't conform to camelCase naming style ('[^\\W\\dA-Z][^\\W_]*$' pattern)":HIGH
-invalid-name:22:0:22:13:say_hello:"Function name ""say_hello"" doesn't conform to camelCase naming style ('([^\\W\\dA-Z][^\\W_]*|__[^\\W\\dA-Z_]\\w+__)$' pattern)":HIGH
+invalid-name:3:0:3:13::"Constant name ""SOME_CONSTANT"" doesn't conform to camelCase naming style ('([^\\W\\dA-Z][^\\W_]*|__.*__)$' pattern)":HIGH
+invalid-name:10:0:10:13:MyClass:"Class name ""MyClass"" doesn't conform to camelCase naming style ('[^\\W\\dA-Z][^\\W_]*$' pattern)":HIGH
+invalid-name:27:0:27:13:say_hello:"Function name ""say_hello"" doesn't conform to camelCase naming style ('(?:__)?([^\\W\\dA-Z][^\\W_]*|__[^\\W\\dA-Z_]\\w+__)$' pattern)":HIGH