Add small bits of typing annotation (#4954)

pylint/reporters/base_reporter.py

@@ -23,7 +23,7 @@ class BaseReporter:
 
     extension = ""
 
-    def __init__(self, output: Optional[TextIO] = None):
+    def __init__(self, output: Optional[TextIO] = None) -> None:
         self.linter: "PyLinter"
         self.section = 0
         self.out: TextIO = output or sys.stdout
@@ -45,7 +45,7 @@ def set_output(self, output: Optional[TextIO] = None) -> None:
         )
         self.out = output or sys.stdout
 
-    def writeln(self, string=""):
+    def writeln(self, string: str = "") -> None:
         """write a line in the output buffer"""
         print(string, file=self.out)
 

pylint/testutils/tokenize_str.py

@@ -3,7 +3,9 @@
 
 import tokenize
 from io import StringIO
+from tokenize import TokenInfo
+from typing import List
 
 
-def _tokenize_str(code):
+def _tokenize_str(code: str) -> List[TokenInfo]:
     return list(tokenize.generate_tokens(StringIO(code).readline))

pylint/utils/pragma_parser.py

@@ -3,7 +3,7 @@
 
 import re
 from collections import namedtuple
-from typing import Generator, List
+from typing import Generator, List, Optional
 
 # Allow stopping after the first semicolon/hash encountered,
 # so that an option can be continued with the reasons
@@ -52,7 +52,7 @@
 )
 
 
-def emit_pragma_representer(action, messages):
+def emit_pragma_representer(action: str, messages: List[str]) -> PragmaRepresenter:
     if not messages and action in MESSAGE_KEYWORDS:
         raise InvalidPragmaError(
             "The keyword is not followed by message identifier", action
@@ -65,7 +65,7 @@ class PragmaParserError(Exception):
     A class for exceptions thrown by pragma_parser module
     """
 
-    def __init__(self, message, token):
+    def __init__(self, message: str, token: str) -> None:
         """
         :args message: explain the reason why the exception has been thrown
         :args token: token concerned by the exception
@@ -88,7 +88,7 @@ class InvalidPragmaError(PragmaParserError):
 
 
 def parse_pragma(pylint_pragma: str) -> Generator[PragmaRepresenter, None, None]:
-    action = None
+    action: Optional[str] = None
     messages: List[str] = []
     assignment_required = False
     previous_token = ""
@@ -113,7 +113,9 @@ def parse_pragma(pylint_pragma: str) -> Generator[PragmaRepresenter, None, None]
                 raise InvalidPragmaError("Missing keyword before assignment", "")
             assignment_required = False
         elif assignment_required:
-            raise InvalidPragmaError("The = sign is missing after the keyword", action)
+            raise InvalidPragmaError(
+                "The = sign is missing after the keyword", action or ""
+            )
         elif kind == "KEYWORD":
             if action:
                 yield emit_pragma_representer(action, messages)