Add flake8 bugbear to pre-commit

.pre-commit-config.yaml

@@ -57,7 +57,8 @@ repos:
     rev: 5.0.4
     hooks:
       - id: flake8
-        additional_dependencies: [flake8-typing-imports==1.14.0]
+        additional_dependencies:
+          [flake8-bugbear==22.10.27, flake8-typing-imports==1.14.0]
         exclude: *fixtures
   - repo: local
     hooks:

pylint/checkers/format.py

@@ -529,7 +529,7 @@ def visit_default(self, node: nodes.NodeNG) -> None:
             tolineno = node.tolineno
         assert tolineno, node
         lines: list[str] = []
-        for line in range(line, tolineno + 1):
+        for line in range(line, tolineno + 1):  # noqa: B020
             self._visited_lines[line] = 1
             try:
                 lines.append(self._lines[line].rstrip())
@@ -676,15 +676,11 @@ def check_lines(
             if tokens.type(line_start) != tokenize.STRING:
                 self.check_trailing_whitespace_ending(line, lineno + offset)
 
-        # hold onto the initial lineno for later
-        potential_line_length_warning = False
-        for offset, line in enumerate(split_lines):
-            # this check is purposefully simple and doesn't rstrip
-            # since this is running on every line you're checking it's
-            # advantageous to avoid doing a lot of work
-            if len(line) > max_chars:
-                potential_line_length_warning = True
-                break
+        # This check is purposefully simple and doesn't rstrip since this is running
+        # on every line you're checking it's advantageous to avoid doing a lot of work
+        potential_line_length_warning = any(
+            len(line) > max_chars for line in split_lines
+        )
 
         # if there were no lines passing the max_chars config, we don't bother
         # running the full line check (as we've met an even more strict condition)

pylint/checkers/strings.py

@@ -834,16 +834,16 @@ def check_for_concatenated_strings(
 
     def process_string_token(self, token: str, start_row: int, start_col: int) -> None:
         quote_char = None
-        index = None
-        for index, char in enumerate(token):
+        for _index, char in enumerate(token):
             if char in "'\"":
                 quote_char = char
                 break
         if quote_char is None:
             return
-
-        prefix = token[:index].lower()  # markers like u, b, r.
-        after_prefix = token[index:]
+        # pylint: disable=undefined-loop-variable
+        prefix = token[:_index].lower()  # markers like u, b, r.
+        after_prefix = token[_index:]
+        # pylint: enable=undefined-loop-variable
         # Chop off quotes
         quote_length = (
             3 if after_prefix[:3] == after_prefix[-3:] == 3 * quote_char else 1

pylint/checkers/typecheck.py

@@ -1584,7 +1584,10 @@ def visit_call(self, node: nodes.Call) -> None:
 
         # 3. Match the **kwargs, if any.
         if node.kwargs:
-            for i, [(name, defval), assigned] in enumerate(parameters):
+            # TODO: It's possible to remove this disable by using dummy-variables-rgx
+            #  see https://github.com/PyCQA/pylint/pull/7697#discussion_r1010832518
+            # pylint: disable-next=unused-variable
+            for i, [(name, _defval), _assigned] in enumerate(parameters):
                 # Assume that *kwargs provides values for all remaining
                 # unassigned named parameters.
                 if name is not None:

pylint/checkers/utils.py

@@ -491,7 +491,7 @@ def only_required_for_messages(
     def store_messages(
         func: AstCallbackMethod[_CheckerT, _NodeT]
     ) -> AstCallbackMethod[_CheckerT, _NodeT]:
-        setattr(func, "checks_msgs", messages)
+        func.checks_msgs = messages  # type: ignore[attr-defined]
         return func
 
     return store_messages

pylint/lint/caching.py

@@ -12,12 +12,14 @@
 from pylint.constants import PYLINT_HOME
 from pylint.utils import LinterStats
 
+PYLINT_HOME_AS_PATH = Path(PYLINT_HOME)
+
 
 def _get_pdata_path(
-    base_name: Path, recurs: int, pylint_home: Path = Path(PYLINT_HOME)
+    base_name: Path, recurs: int, pylint_home: Path = PYLINT_HOME_AS_PATH
 ) -> Path:
-    # We strip all characters that can't be used in a filename
-    # Also strip '/' and '\\' because we want to create a single file, not sub-directories
+    # We strip all characters that can't be used in a filename. Also strip '/' and
+    # '\\' because we want to create a single file, not sub-directories.
     underscored_name = "_".join(
         str(p.replace(":", "_").replace("/", "_").replace("\\", "_"))
         for p in base_name.parts

pylint/message/message_definition_store.py

@@ -52,10 +52,12 @@ def register_message(self, message: MessageDefinition) -> None:
         self._msgs_by_category[message.msgid[0]].append(message.msgid)
 
     # Since MessageDefinitionStore is only initialized once
-    # and the arguments are relatively small in size we do not run the
+    # and the arguments are relatively small we do not run the
     # risk of creating a large memory leak.
     # See discussion in: https://github.com/PyCQA/pylint/pull/5673
-    @functools.lru_cache(maxsize=None)  # pylint: disable=method-cache-max-size-none
+    @functools.lru_cache(  # pylint: disable=method-cache-max-size-none # noqa: B019
+        maxsize=None
+    )
     def get_message_definitions(self, msgid_or_symbol: str) -> list[MessageDefinition]:
         """Returns the Message definition for either a numeric or symbolic id.
 

requirements_test_pre_commit.txt

@@ -2,6 +2,7 @@
 # in .pre-commit-config.yaml
 black==22.10.0
 flake8==5.0.4
+flake8-bugbear==22.10.27
 flake8-typing-imports==1.14.0
 isort==5.10.1
 mypy==0.982

tests/test_check_parallel.py

@@ -239,16 +239,20 @@ def test_linter_with_unpickleable_plugins_is_pickleable(self) -> None:
         linter.load_plugin_modules(["pylint.extensions.overlapping_exceptions"])
         try:
             dill.dumps(linter)
-            assert False, "Plugins loaded were pickle-safe! This test needs altering"
+            raise AssertionError(
+                "Plugins loaded were pickle-safe! This test needs altering"
+            )
         except (KeyError, TypeError, PickleError, NotImplementedError):
             pass
 
         # And expect this call to make it pickle-able
         linter.load_plugin_configuration()
         try:
             dill.dumps(linter)
-        except KeyError:
-            assert False, "Cannot pickle linter when using non-pickleable plugin"
+        except KeyError as exc:
+            raise AssertionError(
+                "Cannot pickle linter when using non-pickleable plugin"
+            ) from exc
 
     def test_worker_check_sequential_checker(self) -> None:
         """Same as test_worker_check_single_file_no_checkers with SequentialTestChecker."""