Add typing to most reference of ``stream``

9 files changed, 85 insertions, 55 deletions

diff --git a/pylint/checkers/misc.py b/pylint/checkers/misc.py
index 60d30c91b..2a0defcb4 100644
--- a/pylint/checkers/misc.py
+++ b/pylint/checkers/misc.py
@@ -28,6 +28,7 @@
 
 import re
 import tokenize
+from typing import Optional
 
 from astroid import nodes
 
@@ -116,13 +117,19 @@ class EncodingChecker(BaseChecker):
 
         self._fixme_pattern = re.compile(regex_string, re.I)
 
-    def _check_encoding(self, lineno, line, file_encoding):
+    def _check_encoding(
+        self, lineno: int, line: bytes, file_encoding: str
+    ) -> Optional[str]:
         try:
             return line.decode(file_encoding)
         except UnicodeDecodeError:
             pass
         except LookupError:
-            if line.startswith("#") and "coding" in line and file_encoding in line:
+            if (
+                line.startswith(b"#")
+                and "coding" in str(line)
+                and file_encoding in str(line)
+            ):
                 msg = f"Cannot decode using encoding '{file_encoding}', bad encoding"
                 self.add_message("syntax-error", line=lineno, args=msg)
         return None
diff --git a/pylint/checkers/similar.py b/pylint/checkers/similar.py
index fb92e7035..4ceb5d660 100644
--- a/pylint/checkers/similar.py
+++ b/pylint/checkers/similar.py
@@ -49,6 +49,7 @@ import re
 import sys
 from collections import defaultdict
 from getopt import getopt
+from io import BufferedIOBase, BufferedReader, BytesIO
 from itertools import chain, groupby
 from typing import (
     Any,
@@ -59,9 +60,11 @@ from typing import (
     List,
     NamedTuple,
     NewType,
+    Optional,
     Set,
     TextIO,
     Tuple,
+    Union,
 )
 
 import astroid
@@ -96,6 +99,9 @@ HashToIndex_T = Dict["LinesChunk", List[Index]]
 # Links index in the lineset's stripped lines to the real lines in the file
 IndexToLines_T = Dict[Index, "SuccessiveLinesLimits"]
 
+# The types the streams read by pylint can take. Originating from astroid.nodes.Module.stream() and open()
+STREAM_TYPES = Union[TextIO, BufferedReader, BytesIO]
+
 
 class CplSuccessiveLinesLimits:
     """
@@ -368,12 +374,16 @@ class Similar:
         self.ignore_signatures = ignore_signatures
         self.linesets: List["LineSet"] = []
 
-    def append_stream(self, streamid: str, stream: TextIO, encoding=None) -> None:
+    def append_stream(
+        self, streamid: str, stream: STREAM_TYPES, encoding: Optional[str] = None
+    ) -> None:
         """append a file to search for similarities"""
-        if encoding is None:
-            readlines = stream.readlines
-        else:
+        if isinstance(stream, BufferedIOBase):
+            if encoding is None:
+                raise ValueError
             readlines = decoding_stream(stream, encoding).readlines
+        else:
+            readlines = stream.readlines  # type: ignore # hint parameter is incorrectly typed as non-optional
         try:
             self.linesets.append(
                 LineSet(
@@ -658,12 +668,12 @@ class LineSet:
 
     def __init__(
         self,
-        name,
-        lines,
-        ignore_comments=False,
-        ignore_docstrings=False,
-        ignore_imports=False,
-        ignore_signatures=False,
+        name: str,
+        lines: List[str],
+        ignore_comments: bool = False,
+        ignore_docstrings: bool = False,
+        ignore_imports: bool = False,
+        ignore_signatures: bool = False,
     ) -> None:
         self.name = name
         self._real_lines = lines
diff --git a/pylint/config/man_help_formatter.py b/pylint/config/man_help_formatter.py
index edef771a4..4b078146d 100644
--- a/pylint/config/man_help_formatter.py
+++ b/pylint/config/man_help_formatter.py
@@ -14,6 +14,7 @@ class _ManHelpFormatter(optparse.HelpFormatter):
         optparse.HelpFormatter.__init__(
             self, indent_increment, max_help_position, width, short_first
         )
+        self.output_level: int
 
     def format_heading(self, heading):
         return f".SH {heading.upper()}\n"
diff --git a/pylint/config/option_manager_mixin.py b/pylint/config/option_manager_mixin.py
index 106ec47cc..c48d20713 100644
--- a/pylint/config/option_manager_mixin.py
+++ b/pylint/config/option_manager_mixin.py
@@ -10,6 +10,8 @@ import functools
 import optparse  # pylint: disable=deprecated-module
 import os
 import sys
+from types import ModuleType
+from typing import Dict, List, Optional, TextIO, Tuple
 
 import toml
 
@@ -186,11 +188,13 @@ class OptionsManagerMixIn:
         """set option on the correct option provider"""
         self._all_options[opt].set_option(opt, value)
 
-    def generate_config(self, stream=None, skipsections=()):
+    def generate_config(
+        self, stream: Optional[TextIO] = None, skipsections: Tuple[str, ...] = ()
+    ) -> None:
         """write a configuration file according to the current configuration
         into the given stream or stdout
         """
-        options_by_section = {}
+        options_by_section: Dict[str, List[Tuple]] = {}
         sections = []
         for provider in self.options_providers:
             for section, options in provider.options_by_section():
@@ -219,7 +223,9 @@ class OptionsManagerMixIn:
             )
             printed = True
 
-    def generate_manpage(self, pkginfo, section=1, stream=sys.stdout):
+    def generate_manpage(
+        self, pkginfo: ModuleType, section: int = 1, stream: TextIO = sys.stdout
+    ) -> None:
         with _patch_optparse():
             formatter = _ManHelpFormatter()
             formatter.output_level = self._maxlevel
diff --git a/pylint/lint/pylinter.py b/pylint/lint/pylinter.py
index 59276a50a..54614ad89 100644
--- a/pylint/lint/pylinter.py
+++ b/pylint/lint/pylinter.py
@@ -13,7 +13,7 @@ import warnings
 from io import TextIOWrapper
 
 import astroid
-from astroid import AstroidError
+from astroid import AstroidError, nodes
 
 from pylint import checkers, config, exceptions, interfaces, reporters
 from pylint.constants import MAIN_CHECKER_NAME, MSG_TYPES
@@ -1180,10 +1180,12 @@ class PyLinter(
 
         return retval
 
-    def _check_astroid_module(self, ast_node, walker, rawcheckers, tokencheckers):
+    def _check_astroid_module(
+        self, node: nodes.Module, walker, rawcheckers, tokencheckers
+    ):
         """Check given AST node with given walker and checkers
 
-        :param astroid.nodes.Module ast_node: AST node of the module to check
+        :param astroid.nodes.Module node: AST node of the module to check
         :param pylint.utils.ast_walker.ASTWalker walker: AST walker
         :param list rawcheckers: List of token checkers to use
         :param list tokencheckers: List of raw checkers to use
@@ -1193,13 +1195,13 @@ class PyLinter(
         :rtype: bool
         """
         try:
-            tokens = utils.tokenize_module(ast_node)
+            tokens = utils.tokenize_module(node)
         except tokenize.TokenError as ex:
             self.add_message("syntax-error", line=ex.args[1][0], args=ex.args[0])
             return None
 
-        if not ast_node.pure_python:
-            self.add_message("raw-checker-failed", args=ast_node.name)
+        if not node.pure_python:
+            self.add_message("raw-checker-failed", args=node.name)
         else:
             # assert astroid.file.endswith('.py')
             # invoke ITokenChecker interface on self to fetch module/block
@@ -1208,14 +1210,14 @@ class PyLinter(
             if self._ignore_file:
                 return False
             # walk ast to collect line numbers
-            self.file_state.collect_block_lines(self.msgs_store, ast_node)
+            self.file_state.collect_block_lines(self.msgs_store, node)
             # run raw and tokens checkers
             for checker in rawcheckers:
-                checker.process_module(ast_node)
+                checker.process_module(node)
             for checker in tokencheckers:
                 checker.process_tokens(tokens)
         # generate events to astroid checkers
-        walker.walk(ast_node)
+        walker.walk(node)
         return True
 
     # IAstroidChecker interface #################################################
diff --git a/pylint/message/message_handler_mix_in.py b/pylint/message/message_handler_mix_in.py
index 00adfa5d9..6d24131a7 100644
--- a/pylint/message/message_handler_mix_in.py
+++ b/pylint/message/message_handler_mix_in.py
@@ -2,7 +2,8 @@
 # For details: https://github.com/PyCQA/pylint/blob/main/LICENSE
 
 import sys
-from typing import List, Tuple, Union
+from io import TextIOWrapper
+from typing import List, TextIO, Tuple, Union
 
 from pylint.constants import (
     _SCOPE_EXEMPT,
@@ -390,20 +391,13 @@ Below is a list of all checkers and their features.
             result += checker.get_full_documentation(**information)
         return result
 
-    def print_full_documentation(self, stream=None):
+    def print_full_documentation(self, stream: TextIO = sys.stdout) -> None:
         """output a full documentation in ReST format"""
-        if not stream:
-            stream = sys.stdout
         print(self.get_checkers_documentation()[:-1], file=stream)
 
     @staticmethod
-    def _print_checker_doc(information, stream=None):
-        """Helper method for print_full_documentation.
-
-        Also used by doc/exts/pylint_extensions.py.
-        """
-        if not stream:
-            stream = sys.stdout
+    def _print_checker_doc(information, stream: TextIOWrapper) -> None:
+        """Helper method used by doc/exts/pylint_extensions.py."""
         checker = information["checker"]
         del information["checker"]
         print(checker.get_full_documentation(**information)[:-1], file=stream)
diff --git a/pylint/reporters/ureports/__init__.py b/pylint/reporters/ureports/__init__.py
index 4126cf4ce..f0651f98c 100644
--- a/pylint/reporters/ureports/__init__.py
+++ b/pylint/reporters/ureports/__init__.py
@@ -18,20 +18,19 @@ formatted as text and html.
 import os
 import sys
 from io import StringIO
+from typing import Iterator, TextIO
 
 
 class BaseWriter:
     """base class for ureport writers"""
 
-    def format(self, layout, stream=None, encoding=None):
+    def format(self, layout, stream: TextIO = sys.stdout, encoding=None) -> None:
         """format and write the given layout into the stream object
 
         unicode policy: unicode strings may be found in the layout;
         try to call stream.write with it, but give it back encoded using
         the given encoding if it fails
         """
-        if stream is None:
-            stream = sys.stdout
         if not encoding:
             encoding = getattr(stream, "encoding", "UTF-8")
         self.encoding = encoding or "UTF-8"
@@ -79,7 +78,7 @@ class BaseWriter:
         result[-1] += [""] * (cols - len(result[-1]))
         return result
 
-    def compute_content(self, layout):
+    def compute_content(self, layout) -> Iterator[str]:
         """trick to compute the formatting of children layout before actually
         writing it
 
diff --git a/pylint/testutils/lint_module_test.py b/pylint/testutils/lint_module_test.py
index 2b5ad2dcb..c15d01271 100644
--- a/pylint/testutils/lint_module_test.py
+++ b/pylint/testutils/lint_module_test.py
@@ -6,8 +6,8 @@ import operator
 import platform
 import sys
 from collections import Counter
-from io import StringIO
-from typing import Dict, List, Optional, Tuple
+from io import StringIO, TextIOWrapper
+from typing import TYPE_CHECKING, Dict, List, Optional, Tuple
 
 import pytest
 from _pytest.config import Config
@@ -24,6 +24,9 @@ from pylint.testutils.output_line import OutputLine
 from pylint.testutils.reporter_for_tests import FunctionalTestReporter
 from pylint.utils import utils
 
+if TYPE_CHECKING:
+    from typing import Counter as CounterType  # typing.Counter added in Python 3.6.1
+
 
 class LintModuleTest:
     maxDiff = None
@@ -88,7 +91,7 @@ class LintModuleTest:
         return f"{self._test_file.base} ({self.__class__.__module__}.{self.__class__.__name__})"
 
     @staticmethod
-    def get_expected_messages(stream):
+    def get_expected_messages(stream: TextIOWrapper) -> "CounterType[Tuple[int, str]]":
         """Parses a file and get expected messages.
 
         :param stream: File-like input stream.
@@ -96,18 +99,18 @@ class LintModuleTest:
         :returns: A dict mapping line,msg-symbol tuples to the count on this line.
         :rtype: dict
         """
-        messages = Counter()
+        messages: "CounterType[Tuple[int, str]]" = Counter()
         for i, line in enumerate(stream):
             match = _EXPECTED_RE.search(line)
             if match is None:
                 continue
             line = match.group("line")
             if line is None:
-                line = i + 1
+                lineno = i + 1
             elif line.startswith("+") or line.startswith("-"):
-                line = i + 1 + int(line)
+                lineno = i + 1 + int(line)
             else:
-                line = int(line)
+                lineno = int(line)
 
             version = match.group("version")
             op = match.group("op")
@@ -117,13 +120,13 @@ class LintModuleTest:
                     continue
 
             for msg_id in match.group("msgs").split(","):
-                messages[line, msg_id.strip()] += 1
+                messages[lineno, msg_id.strip()] += 1
         return messages
 
     @staticmethod
     def multiset_difference(
-        expected_entries: Counter, actual_entries: Counter
-    ) -> Tuple[Counter, Dict[str, int]]:
+        expected_entries: "CounterType", actual_entries: "CounterType"
+    ) -> Tuple["CounterType", Dict[str, int]]:
         """Takes two multisets and compares them.
 
         A multiset is a dict with the cardinality of the key as the value."""
diff --git a/pylint/utils/utils.py b/pylint/utils/utils.py
index c41b35bd7..231983aa6 100644
--- a/pylint/utils/utils.py
+++ b/pylint/utils/utils.py
@@ -17,18 +17,20 @@ import re
 import sys
 import textwrap
 import tokenize
+from io import BufferedReader, BytesIO
 from typing import (
     TYPE_CHECKING,
     List,
     Optional,
     Pattern,
+    TextIO,
     Tuple,
     TypeVar,
     Union,
     overload,
 )
 
-from astroid import Module, modutils
+from astroid import Module, modutils, nodes
 
 from pylint.constants import PY_EXTS
 
@@ -143,7 +145,11 @@ def safe_decode(line, encoding, *args, **kwargs):
         return line.decode(sys.getdefaultencoding(), *args, **kwargs)
 
 
-def decoding_stream(stream, encoding, errors="strict"):
+def decoding_stream(
+    stream: Union[BufferedReader, BytesIO],
+    encoding: str,
+    errors: Literal["strict"] = "strict",
+) -> codecs.StreamReader:
     try:
         reader_cls = codecs.getreader(encoding or sys.getdefaultencoding())
     except LookupError:
@@ -151,8 +157,8 @@ def decoding_stream(stream, encoding, errors="strict"):
     return reader_cls(stream, errors)
 
 
-def tokenize_module(module):
-    with module.stream() as stream:
+def tokenize_module(node: nodes.Module) -> List[tokenize.TokenInfo]:
+    with node.stream() as stream:
         readline = stream.readline
         return list(tokenize.tokenize(readline))
 
@@ -348,7 +354,9 @@ def _format_option_value(optdict, value):
     return value
 
 
-def format_section(stream, section, options, doc=None):
+def format_section(
+    stream: TextIO, section: str, options: List[Tuple], doc: Optional[str] = None
+) -> None:
     """format an options section using the INI format"""
     if doc:
         print(_comment(doc), file=stream)
@@ -356,7 +364,7 @@ def format_section(stream, section, options, doc=None):
     _ini_format(stream, options)
 
 
-def _ini_format(stream, options):
+def _ini_format(stream: TextIO, options: List[Tuple]) -> None:
     """format options using the INI format"""
     for optname, optdict, value in options:
         value = _format_option_value(optdict, value)