WIP: Typing changes left

Author: DanielNoord

pylint/checkers/similar.py

@@ -49,10 +49,11 @@
 import sys
 from collections import defaultdict
 from getopt import getopt
-from io import BufferedIOBase, BufferedReader, BytesIO
+from io import BufferedReader, BytesIO
 from itertools import chain, groupby
 from typing import (
     Any,
+    Callable,
     Dict,
     FrozenSet,
     Generator,
@@ -379,12 +380,10 @@ def append_stream(
         self, streamid: str, stream: STREAM_TYPES, encoding: Optional[str] = None
     ) -> None:
         """append a file to search for similarities"""
-        if isinstance(stream, BufferedIOBase):
-            if encoding is None:
-                raise ValueError
-            readlines = decoding_stream(stream, encoding).readlines
+        if encoding is None:
+            readlines: Union[Callable[..., Union[str, bytes]], Any] = stream.readlines
         else:
-            readlines = stream.readlines  # type: ignore # hint parameter is incorrectly typed as non-optional
+            readlines = decoding_stream(stream, encoding).readlines
         try:
             self.linesets.append(
                 LineSet(

pylint/reporters/base_reporter.py

@@ -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/checker_test_case.py

@@ -2,34 +2,37 @@
 # For details: https://github.com/PyCQA/pylint/blob/main/LICENSE
 
 import contextlib
-from typing import Dict, Optional, Type
+from typing import Dict, Iterator, Type
+
+from astroid.nodes import Module
 
 from pylint.testutils.global_test_linter import linter
+from pylint.testutils.output_line import Message
 from pylint.testutils.unittest_linter import UnittestLinter
 from pylint.utils import ASTWalker
 
 
 class CheckerTestCase:
     """A base testcase class for unit testing individual checker classes."""
 
-    CHECKER_CLASS: Optional[Type] = None
+    CHECKER_CLASS: Type
     CONFIG: Dict = {}
 
-    def setup_method(self):
+    def setup_method(self) -> None:
         self.linter = UnittestLinter()
         self.checker = self.CHECKER_CLASS(self.linter)  # pylint: disable=not-callable
         for key, value in self.CONFIG.items():
             setattr(self.checker.config, key, value)
         self.checker.open()
 
     @contextlib.contextmanager
-    def assertNoMessages(self):
+    def assertNoMessages(self) -> Iterator[None]:
         """Assert that no messages are added by the given method."""
         with self.assertAddsMessages():
             yield
 
     @contextlib.contextmanager
-    def assertAddsMessages(self, *messages):
+    def assertAddsMessages(self, *messages: Message) -> Iterator[None]:
         """Assert that exactly the given method adds the given messages.
 
         The list of messages must exactly match *all* the messages added by the
@@ -47,7 +50,7 @@ def assertAddsMessages(self, *messages):
         )
         assert got == list(messages), msg
 
-    def walk(self, node):
+    def walk(self, node: Module) -> None:
         """recursive walk on the given node"""
         walker = ASTWalker(linter)
         walker.add_checker(self.checker)

pylint/testutils/reporter_for_tests.py

@@ -23,7 +23,7 @@ def __init__(
     ):  # pylint: disable=super-init-not-called # See https://github.com/PyCQA/pylint/issues/4941
         self.reset()
 
-    def reset(self):
+    def reset(self) -> None:
         self.message_ids: Dict = {}
         self.out = StringIO()
         self.path_strip_prefix: str = getcwd() + sep
@@ -45,11 +45,12 @@ def handle_message(self, msg: Message) -> None:
             str_message = str_message.replace("\r\n", "\n")
         self.messages.append(f"{sigle}:{line:>3}{obj}: {str_message}")
 
-    def finalize(self):
+    def finalize(self) -> str:
         self.messages.sort()
         for msg in self.messages:
             print(msg, file=self.out)
-        result = self.out.getvalue()
+        if isinstance(self.out, StringIO):
+            result = self.out.getvalue()
         self.reset()
         return result
 

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/ast_walker.py

@@ -3,28 +3,32 @@
 
 import collections
 import traceback
+from typing import TYPE_CHECKING, Any, Callable, DefaultDict
 
 from astroid import nodes
 
+if TYPE_CHECKING:
+    from pylint.lint.pylinter import PyLinter
+
 
 class ASTWalker:
-    def __init__(self, linter):
+    def __init__(self, linter: "PyLinter") -> None:
         # callbacks per node types
         self.nbstatements = 0
-        self.visit_events = collections.defaultdict(list)
-        self.leave_events = collections.defaultdict(list)
+        self.visit_events: DefaultDict = collections.defaultdict(list)
+        self.leave_events: DefaultDict = collections.defaultdict(list)
         self.linter = linter
         self.exception_msg = False
 
-    def _is_method_enabled(self, method):
+    def _is_method_enabled(self, method: Callable) -> bool:
         if not hasattr(method, "checks_msgs"):
             return True
-        for msg_desc in method.checks_msgs:
+        for msg_desc in method.checks_msgs:  # type: ignore # mypy does not pick up that method always has checks_msgs
             if self.linter.is_message_enabled(msg_desc):
                 return True
         return False
 
-    def add_checker(self, checker):
+    def add_checker(self, checker: Any) -> None:
         """walk to the checker's dir and collect visit and leave methods"""
         vcids = set()
         lcids = set()
@@ -54,7 +58,7 @@ def add_checker(self, checker):
                     visits[cid].append(visit_default)
         # for now we have no "leave_default" method in Pylint
 
-    def walk(self, astroid):
+    def walk(self, astroid: Any) -> None:
         """call visit events of astroid checkers for the given node, recurse on
         its children, then leave events.
         """

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 = ""
@@ -112,7 +112,7 @@ def parse_pragma(pylint_pragma: str) -> Generator[PragmaRepresenter, None, None]
                 # Nothing at all detected before this assignment
                 raise InvalidPragmaError("Missing keyword before assignment", "")
             assignment_required = False
-        elif assignment_required:
+        elif assignment_required and action:
             raise InvalidPragmaError("The = sign is missing after the keyword", action)
         elif kind == "KEYWORD":
             if action:

tests/utils/unittest_ast_walker.py

@@ -42,7 +42,7 @@ def test_check_messages(self) -> None:
         linter = self.MockLinter(
             {"first-message": True, "second-message": False, "third-message": True}
         )
-        walker = ASTWalker(linter)
+        walker = ASTWalker(linter)  # type: ignore # Can't import MockLinter. This needs a refactor
         checker = self.Checker()
         walker.add_checker(checker)
         walker.walk(astroid.parse("x = func()"))
@@ -58,7 +58,7 @@ def visit_assname(self, node):  # pylint: disable=unused-argument
                 self.called = True
 
         linter = self.MockLinter({"first-message": True})
-        walker = ASTWalker(linter)
+        walker = ASTWalker(linter)  # type: ignore # Can't import MockLinter. This needs a refactor
         checker = Checker()
         walker.add_checker(checker)
         with warnings.catch_warnings(record=True):