Rules

Ruff supports over 900 lint rules, many of which are inspired by popular tools like Flake8, isort, pyupgrade, and others. Regardless of the rule's origin, Ruff re-implements every rule in Rust as a first-party feature.

By default, Ruff enables Flake8's F rules, along with a subset of the E rules, omitting any stylistic rules that overlap with the use of a formatter, like ruff format or Black.

If you're just getting started with Ruff, the default rule set is a great place to start: it catches a wide variety of common errors (like unused imports) with zero configuration.

In preview, Ruff enables an expanded set of default rules that includes rules from the B, UP, and RUF categories, as well as many more. If you give the new defaults a try, feel free to leave feedback in the GitHub discussion, where you can also find the new rule set listed in full.

Legend

    🧪     The rule is unstable and is in "preview".
    ⚠️     The rule has been deprecated and will be removed in a future release.
    ❌     The rule has been removed only the documentation is available.
    🛠️     The rule is automatically fixable by the --fix command-line option.

All rules not marked as preview, deprecated or removed are stable.

Airflow (AIR)

For more, see Airflow on PyPI.

Code	Name	Message
AIR001	airflow-variable-name-task-id-mismatch	Task variable name should match the task_id: "{task_id}"
AIR002	airflow-dag-no-schedule-argument	DAG or @dag should have an explicit schedule argument
AIR301	airflow3-removal	{deprecated} is removed in Airflow 3.0	🛠️
AIR302	airflow3-moved-to-provider	{deprecated} is moved into {provider} provider in Airflow 3.0;	🛠️
AIR303	airflow3-incompatible-function-signature	{function_name} signature is changed in Airflow 3.0	🧪
AIR311	airflow3-suggested-update	{deprecated} is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.	🛠️
AIR312	airflow3-suggested-to-move-to-provider	{deprecated} is deprecated and moved into {provider} provider in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.	🛠️
AIR321	airflow31-moved	{deprecated} is moved in Airflow 3.1	🧪🛠️

eradicate (ERA)

For more, see eradicate on PyPI.

Code	Name	Message
ERA001	commented-out-code	Found commented-out code

FastAPI (FAST)

For more, see FastAPI on PyPI.

Code	Name	Message
FAST001	fast-api-redundant-response-model	FastAPI route with redundant response_model argument	🛠️
FAST002	fast-api-non-annotated-dependency	FastAPI dependency without Annotated	🛠️
FAST003	fast-api-unused-path-parameter	Parameter {arg_name} appears in route path, but not in {function_name} signature	🛠️

flake8-2020 (YTT)

For more, see flake8-2020 on PyPI.

Code	Name	Message
YTT101	sys-version-slice3	sys.version[:3] referenced (python3.10), use sys.version_info
YTT102	sys-version2	sys.version[2] referenced (python3.10), use sys.version_info
YTT103	sys-version-cmp-str3	sys.version compared to string (python3.10), use sys.version_info
YTT201	sys-version-info0-eq3	sys.version_info[0] == 3 referenced (python4), use >=
YTT202	six-py3	six.PY3 referenced (python4), use not six.PY2
YTT203	sys-version-info1-cmp-int	sys.version_info[1] compared to integer (python4), compare sys.version_info to tuple
YTT204	sys-version-info-minor-cmp-int	sys.version_info.minor compared to integer (python4), compare sys.version_info to tuple
YTT301	sys-version0	sys.version[0] referenced (python10), use sys.version_info
YTT302	sys-version-cmp-str10	sys.version compared to string (python10), use sys.version_info
YTT303	sys-version-slice1	sys.version[:1] referenced (python10), use sys.version_info

flake8-annotations (ANN)

For more, see flake8-annotations on PyPI.

For related settings, see flake8-annotations.

Code	Name	Message
ANN001	missing-type-function-argument	Missing type annotation for function argument {name}
ANN002	missing-type-args	Missing type annotation for *{name}
ANN003	missing-type-kwargs	Missing type annotation for **{name}
ANN101	missing-type-self	Missing type annotation for {name} in method	❌
ANN102	missing-type-cls	Missing type annotation for {name} in classmethod	❌
ANN201	missing-return-type-undocumented-public-function	Missing return type annotation for public function {name}	🛠️
ANN202	missing-return-type-private-function	Missing return type annotation for private function {name}	🛠️
ANN204	missing-return-type-special-method	Missing return type annotation for special method {name}	🛠️
ANN205	missing-return-type-static-method	Missing return type annotation for staticmethod {name}	🛠️
ANN206	missing-return-type-class-method	Missing return type annotation for classmethod {name}	🛠️
ANN401	any-type	Dynamically typed expressions (typing.Any) are disallowed in {name}

flake8-async (ASYNC)

For more, see flake8-async on PyPI.

Code	Name	Message
ASYNC100	cancel-scope-no-checkpoint	A with {method_name}(...): context does not contain any await statements. This makes it pointless, as the timeout can only be triggered by a checkpoint.
ASYNC105	trio-sync-call	Call to {method_name} is not immediately awaited	🛠️
ASYNC109	async-function-with-timeout	Async function definition with a timeout parameter
ASYNC110	async-busy-wait	Use {module}.Event instead of awaiting {module}.sleep in a while loop
ASYNC115	async-zero-sleep	Use {module}.lowlevel.checkpoint() instead of {module}.sleep(0)	🛠️
ASYNC116	long-sleep-not-forever	{module}.sleep() with >24 hour interval should usually be {module}.sleep_forever()	🛠️
ASYNC210	blocking-http-call-in-async-function	Async functions should not call blocking HTTP methods
ASYNC212	blocking-http-call-httpx-in-async-function	Blocking httpx method {name}.{call}() in async context, use httpx.AsyncClient
ASYNC220	create-subprocess-in-async-function	Async functions should not create subprocesses with blocking methods
ASYNC221	run-process-in-async-function	Async functions should not run processes with blocking methods
ASYNC222	wait-for-process-in-async-function	Async functions should not wait on processes with blocking methods
ASYNC230	blocking-open-call-in-async-function	Async functions should not open files with blocking methods like open
ASYNC240	blocking-path-method-in-async-function	Async functions should not use {path_library} methods, use trio.Path or anyio.path
ASYNC250	blocking-input-in-async-function	Blocking call to input() in async context
ASYNC251	blocking-sleep-in-async-function	Async functions should not call time.sleep

flake8-bandit (S)

For more, see flake8-bandit on PyPI.

For related settings, see flake8-bandit.

Code	Name	Message
S101	assert	Use of assert detected
S102	exec-builtin	Use of exec detected
S103	bad-file-permissions	os.chmod setting a permissive mask {mask:#o} on file or directory
S104	hardcoded-bind-all-interfaces	Possible binding to all interfaces
S105	hardcoded-password-string	Possible hardcoded password assigned to: "{}"
S106	hardcoded-password-func-arg	Possible hardcoded password assigned to argument: "{}"
S107	hardcoded-password-default	Possible hardcoded password assigned to function default: "{}"
S108	hardcoded-temp-file	Probable insecure usage of temporary file or directory: "{}"
S110	try-except-pass	try-except-pass detected, consider logging the exception
S112	try-except-continue	try-except-continue detected, consider logging the exception
S113	request-without-timeout	Probable use of {module} call without timeout
S201	flask-debug-true	Use of debug=True in Flask app detected
S202	tarfile-unsafe-members	Uses of tarfile.extractall()
S301	suspicious-pickle-usage	pickle and modules that wrap it can be unsafe when used to deserialize untrusted data, possible security issue
S302	suspicious-marshal-usage	Deserialization with the marshal module is possibly dangerous
S303	suspicious-insecure-hash-usage	Use of insecure MD2, MD4, MD5, or SHA1 hash function
S304	suspicious-insecure-cipher-usage	Use of insecure cipher, replace with a known secure cipher such as AES
S305	suspicious-insecure-cipher-mode-usage	Use of insecure block cipher mode, replace with a known secure mode such as CBC or CTR
S306	suspicious-mktemp-usage	Use of insecure and deprecated function (mktemp)
S307	suspicious-eval-usage	Use of possibly insecure function; consider using ast.literal_eval
S308	suspicious-mark-safe-usage	Use of mark_safe may expose cross-site scripting vulnerabilities
S310	suspicious-url-open-usage	Audit URL open for permitted schemes. Allowing use of file: or custom schemes is often unexpected.
S311	suspicious-non-cryptographic-random-usage	Standard pseudo-random generators are not suitable for cryptographic purposes
S312	suspicious-telnet-usage	Telnet is considered insecure. Use SSH or some other encrypted protocol.
S313	suspicious-xmlc-element-tree-usage	Using xml to parse untrusted data is known to be vulnerable to XML attacks; use defusedxml equivalents
S314	suspicious-xml-element-tree-usage	Using xml to parse untrusted data is known to be vulnerable to XML attacks; use defusedxml equivalents
S315	suspicious-xml-expat-reader-usage	Using xml to parse untrusted data is known to be vulnerable to XML attacks; use defusedxml equivalents
S316	suspicious-xml-expat-builder-usage	Using xml to parse untrusted data is known to be vulnerable to XML attacks; use defusedxml equivalents
S317	suspicious-xml-sax-usage	Using xml to parse untrusted data is known to be vulnerable to XML attacks; use defusedxml equivalents
S318	suspicious-xml-mini-dom-usage	Using xml to parse untrusted data is known to be vulnerable to XML attacks; use defusedxml equivalents
S319	suspicious-xml-pull-dom-usage	Using xml to parse untrusted data is known to be vulnerable to XML attacks; use defusedxml equivalents
S320	suspicious-xmle-tree-usage	Using lxml to parse untrusted data is known to be vulnerable to XML attacks	❌
S321	suspicious-ftp-lib-usage	FTP-related functions are being called. FTP is considered insecure. Use SSH/SFTP/SCP or some other encrypted protocol.
S323	suspicious-unverified-context-usage	Python allows using an insecure context via the _create_unverified_context that reverts to the previous behavior that does not validate certificates or perform hostname checks.
S324	hashlib-insecure-hash-function	Probable use of insecure hash functions in {library}: {string}
S401	suspicious-telnetlib-import	telnetlib and related modules are considered insecure. Use SSH or another encrypted protocol.	🧪
S402	suspicious-ftplib-import	ftplib and related modules are considered insecure. Use SSH, SFTP, SCP, or another encrypted protocol.	🧪
S403	suspicious-pickle-import	pickle, cPickle, dill, and shelve modules are possibly insecure	🧪
S404	suspicious-subprocess-import	subprocess module is possibly insecure	🧪
S405	suspicious-xml-etree-import	xml.etree methods are vulnerable to XML attacks	🧪
S406	suspicious-xml-sax-import	xml.sax methods are vulnerable to XML attacks	🧪
S407	suspicious-xml-expat-import	xml.dom.expatbuilder is vulnerable to XML attacks	🧪
S408	suspicious-xml-minidom-import	xml.dom.minidom is vulnerable to XML attacks	🧪
S409	suspicious-xml-pulldom-import	xml.dom.pulldom is vulnerable to XML attacks	🧪
S410	suspicious-lxml-import	lxml is vulnerable to XML attacks	❌
S411	suspicious-xmlrpc-import	XMLRPC is vulnerable to remote XML attacks	🧪
S412	suspicious-httpoxy-import	httpoxy is a set of vulnerabilities that affect application code running inCGI, or CGI-like environments. The use of CGI for web applications should be avoided	🧪
S413	suspicious-pycrypto-import	pycrypto library is known to have publicly disclosed buffer overflow vulnerability	🧪
S415	suspicious-pyghmi-import	An IPMI-related module is being imported. Prefer an encrypted protocol over IPMI.	🧪
S501	request-with-no-cert-validation	Probable use of {string} call with verify=False disabling SSL certificate checks
S502	ssl-insecure-version	Call made with insecure SSL protocol: {protocol}
S503	ssl-with-bad-defaults	Argument default set to insecure SSL protocol: {protocol}
S504	ssl-with-no-version	ssl.wrap_socket called without an `ssl_version``
S505	weak-cryptographic-key	{cryptographic_key} key sizes below {minimum_key_size} bits are considered breakable
S506	unsafe-yaml-load	Probable use of unsafe loader {name} with yaml.load. Allows instantiation of arbitrary objects. Consider yaml.safe_load.
S507	ssh-no-host-key-verification	Paramiko call with policy set to automatically trust the unknown host key
S508	snmp-insecure-version	The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
S509	snmp-weak-cryptography	You should not use SNMPv3 without encryption. noAuthNoPriv & authNoPriv is insecure.
S601	paramiko-call	Possible shell injection via Paramiko call; check inputs are properly sanitized
S602	subprocess-popen-with-shell-equals-true	subprocess call with shell=True seems safe, but may be changed in the future; consider rewriting without shell
S603	subprocess-without-shell-equals-true	subprocess call: check for execution of untrusted input
S604	call-with-shell-equals-true	Function call with shell=True parameter identified, security issue
S605	start-process-with-a-shell	Starting a process with a shell: seems safe, but may be changed in the future; consider rewriting without shell
S606	start-process-with-no-shell	Starting a process without a shell
S607	start-process-with-partial-path	Starting a process with a partial executable path
S608	hardcoded-sql-expression	Possible SQL injection vector through string-based query construction
S609	unix-command-wildcard-injection	Possible wildcard injection in call due to * usage
S610	django-extra	Use of Django extra can lead to SQL injection vulnerabilities
S611	django-raw-sql	Use of RawSQL can lead to SQL injection vulnerabilities
S612	logging-config-insecure-listen	Use of insecure logging.config.listen detected
S701	jinja2-autoescape-false	Using jinja2 templates with autoescape=False is dangerous and can lead to XSS. Ensure autoescape=True or use the select_autoescape function.
S702	mako-templates	Mako templates allow HTML and JavaScript rendering by default and are inherently open to XSS attacks
S704	unsafe-markup-use	Unsafe use of {name} detected

flake8-blind-except (BLE)

For more, see flake8-blind-except on PyPI.

Code	Name	Message
BLE001	blind-except	Do not catch blind exception: {name}

flake8-boolean-trap (FBT)

For more, see flake8-boolean-trap on PyPI.

For related settings, see flake8-boolean-trap.

Code	Name	Message
FBT001	boolean-type-hint-positional-argument	Boolean-typed positional argument in function definition
FBT002	boolean-default-value-positional-argument	Boolean default positional argument in function definition
FBT003	boolean-positional-value-in-call	Boolean positional value in function call

flake8-bugbear (B)

For more, see flake8-bugbear on PyPI.

For related settings, see flake8-bugbear.

Code	Name	Message
B002	unary-prefix-increment-decrement	Python does not support the unary prefix increment operator (++)
B003	assignment-to-os-environ	Assigning to os.environ doesn't clear the environment
B004	unreliable-callable-check	Using hasattr(x, "__call__") to test if x is callable is unreliable. Use callable(x) for consistent results.	🛠️
B005	strip-with-multi-characters	Using .strip() with multi-character strings is misleading
B006	mutable-argument-default	Do not use mutable data structures for argument defaults	🛠️
B007	unused-loop-control-variable	Loop control variable {name} not used within loop body	🛠️
B008	function-call-in-default-argument	Do not perform function call {name} in argument defaults; instead, perform the call within the function, or read the default from a module-level singleton variable
B009	get-attr-with-constant	Do not call getattr with a constant attribute value. It is not any safer than normal property access.	🛠️
B010	set-attr-with-constant	Do not call setattr with a constant attribute value. It is not any safer than normal property access.	🛠️
B011	assert-false	Do not assert False (python -O removes these calls), raise AssertionError()	🛠️
B012	jump-statement-in-finally	{name} inside finally blocks cause exceptions to be silenced
B013	redundant-tuple-in-exception-handler	A length-one tuple literal is redundant in exception handlers	🛠️
B014	duplicate-handler-exception	Exception handler with duplicate exception: {name}	🛠️
B015	useless-comparison	Pointless comparison. Did you mean to assign a value? Otherwise, prepend assert or remove it.
B016	raise-literal	Cannot raise a literal. Did you intend to return it or raise an Exception?
B017	assert-raises-exception	Do not assert blind exception: {exception}
B018	useless-expression	Found useless expression. Either assign it to a variable or remove it.
B019	cached-instance-method	Use of functools.lru_cache or functools.cache on methods can lead to memory leaks
B020	loop-variable-overrides-iterator	Loop control variable {name} overrides iterable it iterates
B021	f-string-docstring	f-string used as docstring. Python will interpret this as a joined string, rather than a docstring.
B022	useless-contextlib-suppress	No arguments passed to contextlib.suppress. No exceptions will be suppressed and therefore this context manager is redundant
B023	function-uses-loop-variable	Function definition does not bind loop variable {name}
B024	abstract-base-class-without-abstract-method	{name} is an abstract base class, but it has no abstract methods or properties
B025	duplicate-try-block-exception	try-except* block with duplicate exception {name}
B026	star-arg-unpacking-after-keyword-arg	Star-arg unpacking after a keyword argument is strongly discouraged
B027	empty-method-without-abstract-decorator	{name} is an empty method in an abstract base class, but has no abstract decorator
B028	no-explicit-stacklevel	No explicit stacklevel keyword argument found	🛠️
B029	except-with-empty-tuple	Using except* (): with an empty tuple does not catch anything; add exceptions to handle
B030	except-with-non-exception-classes	except* handlers should only be exception classes or tuples of exception classes
B031	reuse-of-groupby-generator	Using the generator returned from itertools.groupby() more than once will do nothing on the second usage
B032	unintentional-type-annotation	Possible unintentional type annotation (using :). Did you mean to assign (using =)?
B033	duplicate-value	Sets should not contain duplicate item {value}	🛠️
B034	re-sub-positional-args	{method} should pass {param_name} and flags as keyword arguments to avoid confusion due to unintuitive argument positions
B035	static-key-dict-comprehension	Dictionary comprehension uses static key: {key}
B039	mutable-contextvar-default	Do not use mutable data structures for ContextVar defaults
B901	return-in-generator	Using yield and return {value} in a generator function can lead to confusing behavior	🧪
B903	class-as-data-structure	Class could be dataclass or namedtuple	🧪
B904	raise-without-from-inside-except	Within an except* clause, raise exceptions with raise ... from err or raise ... from None to distinguish them from errors in exception handling
B905	zip-without-explicit-strict	zip() without an explicit strict= parameter	🛠️
B909	loop-iterator-mutation	Mutation to loop iterable {name} during iteration	🧪
B911	batched-without-explicit-strict	itertools.batched() without an explicit strict parameter
B912	map-without-explicit-strict	map() without an explicit strict= parameter	🛠️

flake8-builtins (A)

For more, see flake8-builtins on PyPI.

For related settings, see flake8-builtins.

Code	Name	Message
A001	builtin-variable-shadowing	Variable {name} is shadowing a Python builtin
A002	builtin-argument-shadowing	Function argument {name} is shadowing a Python builtin
A003	builtin-attribute-shadowing	Python builtin is shadowed by class attribute {name} from {row}
A004	builtin-import-shadowing	Import {name} is shadowing a Python builtin
A005	stdlib-module-shadowing	Module {name} shadows a Python standard-library module
A006	builtin-lambda-argument-shadowing	Lambda argument {name} is shadowing a Python builtin

flake8-commas (COM)

For more, see flake8-commas on PyPI.

Code	Name	Message
COM812	missing-trailing-comma	Trailing comma missing	🛠️
COM818	trailing-comma-on-bare-tuple	Trailing comma on bare tuple prohibited
COM819	prohibited-trailing-comma	Trailing comma prohibited	🛠️

flake8-comprehensions (C4)

For more, see flake8-comprehensions on PyPI.

For related settings, see flake8-comprehensions.

Code	Name	Message
C400	unnecessary-generator-list	Unnecessary generator (rewrite using list())	🛠️
C401	unnecessary-generator-set	Unnecessary generator (rewrite using set())	🛠️
C402	unnecessary-generator-dict	Unnecessary generator (rewrite as a dict comprehension)	🛠️
C403	unnecessary-list-comprehension-set	Unnecessary list comprehension (rewrite as a set comprehension)	🛠️
C404	unnecessary-list-comprehension-dict	Unnecessary list comprehension (rewrite as a dict comprehension)	🛠️
C405	unnecessary-literal-set	Unnecessary {kind} literal (rewrite as a set literal)	🛠️
C406	unnecessary-literal-dict	Unnecessary {obj_type} literal (rewrite as a dict literal)	🛠️
C408	unnecessary-collection-call	Unnecessary {kind}() call (rewrite as a literal)	🛠️
C409	unnecessary-literal-within-tuple-call	Unnecessary list literal passed to tuple() (rewrite as a tuple literal)	🛠️
C410	unnecessary-literal-within-list-call	Unnecessary list literal passed to list() (remove the outer call to list())	🛠️
C411	unnecessary-list-call	Unnecessary list() call (remove the outer call to list())	🛠️
C413	unnecessary-call-around-sorted	Unnecessary {func}() call around sorted()	🛠️
C414	unnecessary-double-cast-or-process	Unnecessary {inner}() call within {outer}()	🛠️
C415	unnecessary-subscript-reversal	Unnecessary subscript reversal of iterable within {func}()
C416	unnecessary-comprehension	Unnecessary {kind} comprehension (rewrite using {kind}())	🛠️
C417	unnecessary-map	Unnecessary map() usage (rewrite using a {object_type})	🛠️
C418	unnecessary-literal-within-dict-call	Unnecessary dict {kind} passed to dict() (remove the outer call to dict())	🛠️
C419	unnecessary-comprehension-in-call	Unnecessary list comprehension	🛠️
C420	unnecessary-dict-comprehension-for-iterable	Unnecessary dict comprehension for iterable; use dict.fromkeys instead	🛠️

flake8-copyright (CPY)

For more, see flake8-copyright on PyPI.

For related settings, see flake8-copyright.

Code	Name	Message
CPY001	missing-copyright-notice	Missing copyright notice at top of file	🧪

flake8-datetimez (DTZ)

For more, see flake8-datetimez on PyPI.

Code	Name	Message
DTZ001	call-datetime-without-tzinfo	datetime.datetime() called without a tzinfo argument
DTZ002	call-datetime-today	datetime.datetime.today() used
DTZ003	call-datetime-utcnow	datetime.datetime.utcnow() used
DTZ004	call-datetime-utcfromtimestamp	datetime.datetime.utcfromtimestamp() used
DTZ005	call-datetime-now-without-tzinfo	datetime.datetime.now() called without a tz argument
DTZ006	call-datetime-fromtimestamp	datetime.datetime.fromtimestamp() called without a tz argument
DTZ007	call-datetime-strptime-without-zone	Naive datetime constructed using datetime.datetime.strptime() without %z
DTZ011	call-date-today	datetime.date.today() used
DTZ012	call-date-fromtimestamp	datetime.date.fromtimestamp() used
DTZ901	datetime-min-max	Use of datetime.datetime.{min_max} without timezone information

flake8-debugger (T10)

For more, see flake8-debugger on PyPI.

Code	Name	Message
T100	debugger	Trace found: {name} used

flake8-django (DJ)

For more, see flake8-django on PyPI.

Code	Name	Message
DJ001	django-nullable-model-string-field	Avoid using null=True on string-based fields such as {field_name}
DJ003	django-locals-in-render-function	Avoid passing locals() as context to a render function
DJ006	django-exclude-with-model-form	Do not use exclude with ModelForm, use fields instead
DJ007	django-all-with-model-form	Do not use __all__ with ModelForm, use fields instead
DJ008	django-model-without-dunder-str	Model does not define __str__ method
DJ012	django-unordered-body-content-in-model	Order of model's inner classes, methods, and fields does not follow the Django Style Guide: {element_type} should come before {prev_element_type}
DJ013	django-non-leading-receiver-decorator	@receiver decorator must be on top of all the other decorators

flake8-errmsg (EM)

For more, see flake8-errmsg on PyPI.

For related settings, see flake8-errmsg.

Code	Name	Message
EM101	raw-string-in-exception	Exception must not use a string literal, assign to variable first	🛠️
EM102	f-string-in-exception	Exception must not use an f-string literal, assign to variable first	🛠️
EM103	dot-format-in-exception	Exception must not use a .format() string directly, assign to variable first	🛠️

flake8-executable (EXE)

For more, see flake8-executable on PyPI.

Code	Name	Message
EXE001	shebang-not-executable	Shebang is present but file is not executable
EXE002	shebang-missing-executable-file	The file is executable but no shebang is present
EXE003	shebang-missing-python	Shebang should contain python, pytest, or uv run
EXE004	shebang-leading-whitespace	Avoid whitespace before shebang	🛠️
EXE005	shebang-not-first-line	Shebang should be at the beginning of the file

flake8-fixme (FIX)

For more, see flake8-fixme on GitHub.

Code	Name	Message
FIX001	line-contains-fixme	Line contains FIXME, consider resolving the issue
FIX002	line-contains-todo	Line contains TODO, consider resolving the issue
FIX003	line-contains-xxx	Line contains XXX, consider resolving the issue
FIX004	line-contains-hack	Line contains HACK, consider resolving the issue

flake8-future-annotations (FA)

For more, see flake8-future-annotations on PyPI.

Code	Name	Message
FA100	future-rewritable-type-annotation	Add from __future__ import annotations to simplify {name}	🛠️
FA102	future-required-type-annotation	Missing from __future__ import annotations, but uses {reason}	🛠️

flake8-gettext (INT)

For more, see flake8-gettext on PyPI.

For related settings, see flake8-gettext.

Code	Name	Message
INT001	f-string-in-get-text-func-call	f-string in plural argument is resolved before function call
INT002	format-in-get-text-func-call	format method in plural argument is resolved before function call
INT003	printf-in-get-text-func-call	printf-style format in plural argument is resolved before function call

flake8-implicit-str-concat (ISC)

For more, see flake8-implicit-str-concat on PyPI.

For related settings, see flake8-implicit-str-concat.

Code	Name	Message
ISC001	single-line-implicit-string-concatenation	Implicitly concatenated string literals on one line	🛠️
ISC002	multi-line-implicit-string-concatenation	Implicitly concatenated string literals over multiple lines
ISC003	explicit-string-concatenation	Explicitly concatenated string should be implicitly concatenated	🛠️
ISC004	implicit-string-concatenation-in-collection-literal	Unparenthesized implicit string concatenation in collection	🧪🛠️

flake8-import-conventions (ICN)

For more, see flake8-import-conventions on GitHub.

For related settings, see flake8-import-conventions.

Code	Name	Message
ICN001	unconventional-import-alias	{name} should be imported as {asname}	🛠️
ICN002	banned-import-alias	{name} should not be imported as {asname}
ICN003	banned-import-from	Members of {name} should not be imported explicitly

flake8-logging (LOG)

For more, see flake8-logging on PyPI.

Code	Name	Message
LOG001	direct-logger-instantiation	Use logging.getLogger() to instantiate loggers	🛠️
LOG002	invalid-get-logger-argument	Use __name__ with logging.getLogger()	🛠️
LOG004	log-exception-outside-except-handler	.exception() call outside exception handlers	🧪🛠️
LOG007	exception-without-exc-info	Use of logging.exception with falsy exc_info
LOG009	undocumented-warn	Use of undocumented logging.WARN constant	🛠️
LOG014	exc-info-outside-except-handler	exc_info= outside exception handlers	🛠️
LOG015	root-logger-call	{}() call on root logger

flake8-logging-format (G)

For more, see flake8-logging-format on PyPI.

Code	Name	Message
G001	logging-string-format	Logging statement uses str.format
G002	logging-percent-format	Logging statement uses %
G003	logging-string-concat	Logging statement uses +
G004	logging-f-string	Logging statement uses f-string	🛠️
G010	logging-warn	Logging statement uses warn instead of warning	🛠️
G101	logging-extra-attr-clash	Logging statement uses an extra field that clashes with a LogRecord field: {key}
G201	logging-exc-info	Logging .exception(...) should be used instead of .error(..., exc_info=True)
G202	logging-redundant-exc-info	Logging statement has redundant exc_info

flake8-no-pep420 (INP)

For more, see flake8-no-pep420 on PyPI.

Code	Name	Message
INP001	implicit-namespace-package	File {filename} is part of an implicit namespace package. Add an __init__.py.

flake8-pie (PIE)

For more, see flake8-pie on PyPI.

Code	Name	Message
PIE790	unnecessary-placeholder	Unnecessary pass statement	🛠️
PIE794	duplicate-class-field-definition	Class field {name} is defined multiple times	🛠️
PIE796	non-unique-enums	Enum contains duplicate value: {value}
PIE800	unnecessary-spread	Unnecessary spread **	🛠️
PIE804	unnecessary-dict-kwargs	Unnecessary dict kwargs	🛠️
PIE807	reimplemented-container-builtin	Prefer {container} over useless lambda	🛠️
PIE808	unnecessary-range-start	Unnecessary start argument in range	🛠️
PIE810	multiple-starts-ends-with	Call {attr} once with a tuple	🛠️

flake8-print (T20)

For more, see flake8-print on PyPI.

Code	Name	Message
T201	print	print found	🛠️
T203	p-print	pprint found	🛠️

flake8-pyi (PYI)

For more, see flake8-pyi on PyPI.

Code	Name	Message
PYI001	unprefixed-type-param	Name of private {kind} must start with _
PYI002	complex-if-statement-in-stub	if test must be a simple comparison against sys.platform or sys.version_info
PYI003	unrecognized-version-info-check	Unrecognized sys.version_info check
PYI004	patch-version-comparison	Version comparison must use only major and minor version
PYI005	wrong-tuple-length-version-comparison	Version comparison must be against a length-{expected_length} tuple
PYI006	bad-version-info-comparison	Use < or >= for sys.version_info comparisons
PYI007	unrecognized-platform-check	Unrecognized sys.platform check
PYI008	unrecognized-platform-name	Unrecognized platform {platform}
PYI009	pass-statement-stub-body	Empty body should contain ..., not pass	🛠️
PYI010	non-empty-stub-body	Function body must contain only ...	🛠️
PYI011	typed-argument-default-in-stub	Only simple default values allowed for typed arguments	🛠️
PYI012	pass-in-class-body	Class body must not contain pass	🛠️
PYI013	ellipsis-in-non-empty-class-body	Non-empty class body must not contain ...	🛠️
PYI014	argument-default-in-stub	Only simple default values allowed for arguments	🛠️
PYI015	assignment-default-in-stub	Only simple default values allowed for assignments	🛠️
PYI016	duplicate-union-member	Duplicate union member {}	🛠️
PYI017	complex-assignment-in-stub	Stubs should not contain assignments to attributes or multiple targets
PYI018	unused-private-type-var	Private {type_var_like_kind} {type_var_like_name} is never used	🛠️
PYI019	custom-type-var-for-self	Use Self instead of custom TypeVar {}	🛠️
PYI020	quoted-annotation-in-stub	Quoted annotations should not be included in stubs	🛠️
PYI021	docstring-in-stub	Docstrings should not be included in stubs	🛠️
PYI024	collections-named-tuple	Use typing.NamedTuple instead of collections.namedtuple
PYI025	unaliased-collections-abc-set-import	Use from collections.abc import Set as AbstractSet to avoid confusion with the set builtin	🛠️
PYI026	type-alias-without-annotation	Use {module}.TypeAlias for type alias, e.g., {name}: TypeAlias = {value}	🛠️
PYI029	str-or-repr-defined-in-stub	Defining {name} in a stub is almost always redundant	🛠️
PYI030	unnecessary-literal-union	Multiple literal members in a union. Use a single literal, e.g. Literal[{}]	🛠️
PYI032	any-eq-ne-annotation	Prefer object to Any for the second parameter to {method_name}	🛠️
PYI033	type-comment-in-stub	Don't use type comments in stub file
PYI034	non-self-return-type	__new__ methods usually return self at runtime	🛠️
PYI035	unassigned-special-variable-in-stub	{name} in a stub file must have a value, as it has the same semantics as {name} at runtime
PYI036	bad-exit-annotation	Star-args in {method_name} should be annotated with object	🛠️
PYI041	redundant-numeric-union	Use {supertype} instead of {subtype} | {supertype}	🛠️
PYI042	snake-case-type-alias	Type alias {name} should be CamelCase
PYI043	t-suffixed-type-alias	Private type alias {name} should not be suffixed with T (the T suffix implies that an object is a TypeVar)
PYI044	future-annotations-in-stub	from __future__ import annotations has no effect in stub files, since type checkers automatically treat stubs as having those semantics	🛠️
PYI045	iter-method-return-iterable	__aiter__ methods should return an AsyncIterator, not an AsyncIterable
PYI046	unused-private-protocol	Private protocol {name} is never used
PYI047	unused-private-type-alias	Private TypeAlias {name} is never used
PYI048	stub-body-multiple-statements	Function body must contain exactly one statement
PYI049	unused-private-typed-dict	Private TypedDict {name} is never used
PYI050	no-return-argument-annotation-in-stub	Prefer {module}.Never over NoReturn for argument annotations
PYI051	redundant-literal-union	Literal[{literal}] is redundant in a union with {builtin_type}
PYI052	unannotated-assignment-in-stub	Need type annotation for {name}
PYI053	string-or-bytes-too-long	String and bytes literals longer than 50 characters are not permitted	🛠️
PYI054	numeric-literal-too-long	Numeric literals with a string representation longer than ten characters are not permitted	🛠️
PYI055	unnecessary-type-union	Multiple type members in a union. Combine them into one, e.g., type[{union_str}].	🛠️
PYI056	unsupported-method-call-on-all	Calling .{name}() on __all__ may not be supported by all type checkers (use += instead)
PYI057	byte-string-usage	Do not use {origin}.ByteString, which has unclear semantics and is deprecated
PYI058	generator-return-from-iter-method	Use {return_type} as the return value for simple {method} methods	🛠️
PYI059	generic-not-last-base-class	Generic[] should always be the last base class	🛠️
PYI061	redundant-none-literal	Use None rather than Literal[None]	🛠️
PYI062	duplicate-literal-member	Duplicate literal member {}	🛠️
PYI063	pep484-style-positional-only-parameter	Use PEP 570 syntax for positional-only parameters
PYI064	redundant-final-literal	Final[Literal[{literal}]] can be replaced with a bare Final	🛠️
PYI066	bad-version-info-order	Put branches for newer Python versions first when branching on sys.version_info comparisons

flake8-pytest-style (PT)

For more, see flake8-pytest-style on PyPI.

For related settings, see flake8-pytest-style.

Code	Name	Message
PT001	pytest-fixture-incorrect-parentheses-style	Use @pytest.fixture{expected} over @pytest.fixture{actual}	🛠️
PT002	pytest-fixture-positional-args	Configuration for fixture {function} specified via positional args, use kwargs
PT003	pytest-extraneous-scope-function	scope='function' is implied in @pytest.fixture()	🛠️
PT004	pytest-missing-fixture-name-underscore	Fixture {function} does not return anything, add leading underscore	❌
PT005	pytest-incorrect-fixture-name-underscore	Fixture {function} returns a value, remove leading underscore	❌
PT006	pytest-parametrize-names-wrong-type	Wrong type passed to first argument of pytest.mark.parametrize; expected {expected_string}	🛠️
PT007	pytest-parametrize-values-wrong-type	Wrong values type in pytest.mark.parametrize expected {values} of {row}	🛠️
PT008	pytest-patch-with-lambda	Use return_value= instead of patching with lambda
PT009	pytest-unittest-assertion	Use a regular assert instead of unittest-style {assertion}	🛠️
PT010	pytest-raises-without-exception	Set the expected exception in pytest.raises()
PT011	pytest-raises-too-broad	pytest.raises({exception}) is too broad, set the match parameter or use a more specific exception
PT012	pytest-raises-with-multiple-statements	pytest.raises() block should contain a single simple statement
PT013	pytest-incorrect-pytest-import	Incorrect import of pytest; use import pytest instead
PT014	pytest-duplicate-parametrize-test-cases	Duplicate of test case at index {index} in pytest.mark.parametrize	🛠️
PT015	pytest-assert-always-false	Assertion always fails, replace with pytest.fail()
PT016	pytest-fail-without-message	No message passed to pytest.fail()
PT017	pytest-assert-in-except	Found assertion on exception {name} in except block, use pytest.raises() instead
PT018	pytest-composite-assertion	Assertion should be broken down into multiple parts	🛠️
PT019	pytest-fixture-param-without-value	Fixture {name} without value is injected as parameter, use @pytest.mark.usefixtures instead
PT020	pytest-deprecated-yield-fixture	@pytest.yield_fixture is deprecated, use @pytest.fixture
PT021	pytest-fixture-finalizer-callback	Use yield instead of request.addfinalizer
PT022	pytest-useless-yield-fixture	No teardown in fixture {name}, use return instead of yield	🛠️
PT023	pytest-incorrect-mark-parentheses-style	Use @pytest.mark.{mark_name}{expected_parens} over @pytest.mark.{mark_name}{actual_parens}	🛠️
PT024	pytest-unnecessary-asyncio-mark-on-fixture	pytest.mark.asyncio is unnecessary for fixtures	🛠️
PT025	pytest-erroneous-use-fixtures-on-fixture	pytest.mark.usefixtures has no effect on fixtures	🛠️
PT026	pytest-use-fixtures-without-parameters	Useless pytest.mark.usefixtures without parameters	🛠️
PT027	pytest-unittest-raises-assertion	Use pytest.raises instead of unittest-style {assertion}	🛠️
PT028	pytest-parameter-with-default-argument	Test function parameter {} has default argument
PT029	pytest-warns-without-warning	Set the expected warning in pytest.warns()	🧪
PT030	pytest-warns-too-broad	pytest.warns({warning}) is too broad, set the match parameter or use a more specific warning
PT031	pytest-warns-with-multiple-statements	pytest.warns() block should contain a single simple statement

flake8-quotes (Q)

For more, see flake8-quotes on PyPI.

For related settings, see flake8-quotes.

Code	Name	Message
Q000	bad-quotes-inline-string	Single quotes found but double quotes preferred	🛠️
Q001	bad-quotes-multiline-string	Single quote multiline found but double quotes preferred	🛠️
Q002	bad-quotes-docstring	Single quote docstring found but double quotes preferred	🛠️
Q003	avoidable-escaped-quote	Change outer quotes to avoid escaping inner quotes	🛠️
Q004	unnecessary-escaped-quote	Unnecessary escape on inner quote character	🛠️

flake8-raise (RSE)

For more, see flake8-raise on PyPI.

Code	Name	Message
RSE102	unnecessary-paren-on-raise-exception	Unnecessary parentheses on raised exception	🛠️

flake8-return (RET)

For more, see flake8-return on PyPI.

Code	Name	Message
RET501	unnecessary-return-none	Do not explicitly return None in function if it is the only possible return value	🛠️
RET502	implicit-return-value	Do not implicitly return None in function able to return non-None value	🛠️
RET503	implicit-return	Missing explicit return at the end of function able to return non-None value	🛠️
RET504	unnecessary-assign	Unnecessary assignment to {name} before return statement	🛠️
RET505	superfluous-else-return	Unnecessary {branch} after return statement	🛠️
RET506	superfluous-else-raise	Unnecessary {branch} after raise statement	🛠️
RET507	superfluous-else-continue	Unnecessary {branch} after continue statement	🛠️
RET508	superfluous-else-break	Unnecessary {branch} after break statement	🛠️

flake8-self (SLF)

For more, see flake8-self on PyPI.

For related settings, see flake8-self.

Code	Name	Message
SLF001	private-member-access	Private member accessed: {access}

flake8-simplify (SIM)

For more, see flake8-simplify on PyPI.

Code	Name	Message
SIM101	duplicate-isinstance-call	Multiple isinstance calls for {name}, merge into a single call	🛠️
SIM102	collapsible-if	Use a single if statement instead of nested if statements	🛠️
SIM103	needless-bool	Return the condition {condition} directly	🛠️
SIM105	suppressible-exception	Use contextlib.suppress({exception}) instead of try-except-pass	🛠️
SIM107	return-in-try-except-finally	Don't use return in try-except and finally
SIM108	if-else-block-instead-of-if-exp	Use ternary operator {contents} instead of if-else-block	🛠️
SIM109	compare-with-tuple	Use {replacement} instead of multiple equality comparisons	🛠️
SIM110	reimplemented-builtin	Use {replacement} instead of for loop	🛠️
SIM112	uncapitalized-environment-variables	Use capitalized environment variable {expected} instead of {actual}	🛠️
SIM113	enumerate-for-loop	Use enumerate() for index variable {index} in for loop
SIM114	if-with-same-arms	Combine if branches using logical or operator	🛠️
SIM115	open-file-with-context-handler	Use a context manager for opening files
SIM116	if-else-block-instead-of-dict-lookup	Use a dictionary instead of consecutive if statements
SIM117	multiple-with-statements	Use a single with statement with multiple contexts instead of nested with statements	🛠️
SIM118	in-dict-keys	Use key {operator} dict instead of key {operator} dict.keys()	🛠️
SIM201	negate-equal-op	Use {left} != {right} instead of not {left} == {right}	🛠️
SIM202	negate-not-equal-op	Use {left} == {right} instead of not {left} != {right}	🛠️
SIM208	double-negation	Use {expr} instead of not (not {expr})	🛠️
SIM210	if-expr-with-true-false	Remove unnecessary True if ... else False	🛠️
SIM211	if-expr-with-false-true	Use not ... instead of False if ... else True	🛠️
SIM212	if-expr-with-twisted-arms	Use {expr_else} if {expr_else} else {expr_body} instead of {expr_body} if not {expr_else} else {expr_else}	🛠️
SIM220	expr-and-not-expr	Use False instead of {name} and not {name}	🛠️
SIM221	expr-or-not-expr	Use True instead of {name} or not {name}	🛠️
SIM222	expr-or-true	Use {expr} instead of {replaced}	🛠️
SIM223	expr-and-false	Use {expr} instead of {replaced}	🛠️
SIM300	yoda-conditions	Yoda condition detected	🛠️
SIM401	if-else-block-instead-of-dict-get	Use {contents} instead of an if block	🛠️
SIM905	split-static-string	Consider using a list literal instead of str.{}	🛠️
SIM910	dict-get-with-none-default	Use {expected} instead of {actual}	🛠️
SIM911	zip-dict-keys-and-values	Use {expected} instead of {actual}	🛠️

flake8-slots (SLOT)

For more, see flake8-slots on PyPI.

Code	Name	Message
SLOT000	no-slots-in-str-subclass	Subclasses of str should define __slots__
SLOT001	no-slots-in-tuple-subclass	Subclasses of tuple should define __slots__
SLOT002	no-slots-in-namedtuple-subclass	Subclasses of {namedtuple_kind} should define __slots__

flake8-tidy-imports (TID)

For more, see flake8-tidy-imports on PyPI.

For related settings, see flake8-tidy-imports.

Code	Name	Message
TID251	banned-api	{name} is banned: {message}
TID252	relative-imports	Prefer absolute imports over relative imports from parent modules	🛠️
TID253	banned-module-level-imports	{name} is banned at the module level

flake8-todos (TD)

For more, see flake8-todos on GitHub.

Code	Name	Message
TD001	invalid-todo-tag	Invalid TODO tag: {tag}
TD002	missing-todo-author	Missing author in TODO; try: # TODO(<author_name>): ... or # TODO @<author_name>: ...
TD003	missing-todo-link	Missing issue link for this TODO
TD004	missing-todo-colon	Missing colon in TODO
TD005	missing-todo-description	Missing issue description after TODO
TD006	invalid-todo-capitalization	Invalid TODO capitalization: {tag} should be TODO	🛠️
TD007	missing-space-after-todo-colon	Missing space after colon in TODO

flake8-type-checking (TC)

For more, see flake8-type-checking on PyPI.

For related settings, see flake8-type-checking.

Code	Name	Message
TC001	typing-only-first-party-import	Move application import {} into a type-checking block	🛠️
TC002	typing-only-third-party-import	Move third-party import {} into a type-checking block	🛠️
TC003	typing-only-standard-library-import	Move standard library import {} into a type-checking block	🛠️
TC004	runtime-import-in-type-checking-block	Move import {qualified_name} out of type-checking block. Import is used for more than type hinting.	🛠️
TC005	empty-type-checking-block	Found empty type-checking block	🛠️
TC006	runtime-cast-value	Add quotes to type expression in typing.cast()	🛠️
TC007	unquoted-type-alias	Add quotes to type alias	🛠️
TC008	quoted-type-alias	Remove quotes from type alias	🧪🛠️
TC010	runtime-string-union	Invalid string member in X | Y-style union type

flake8-unused-arguments (ARG)

For more, see flake8-unused-arguments on PyPI.

For related settings, see flake8-unused-arguments.

Code	Name	Message
ARG001	unused-function-argument	Unused function argument: {name}
ARG002	unused-method-argument	Unused method argument: {name}
ARG003	unused-class-method-argument	Unused class method argument: {name}
ARG004	unused-static-method-argument	Unused static method argument: {name}
ARG005	unused-lambda-argument	Unused lambda argument: {name}

flake8-use-pathlib (PTH)

For more, see flake8-use-pathlib on PyPI.

Code	Name	Message
PTH100	os-path-abspath	os.path.abspath() should be replaced by Path.resolve()	🛠️
PTH101	os-chmod	os.chmod() should be replaced by Path.chmod()	🛠️
PTH102	os-mkdir	os.mkdir() should be replaced by Path.mkdir()	🛠️
PTH103	os-makedirs	os.makedirs() should be replaced by Path.mkdir(parents=True)	🛠️
PTH104	os-rename	os.rename() should be replaced by Path.rename()	🛠️
PTH105	os-replace	os.replace() should be replaced by Path.replace()	🛠️
PTH106	os-rmdir	os.rmdir() should be replaced by Path.rmdir()	🛠️
PTH107	os-remove	os.remove() should be replaced by Path.unlink()	🛠️
PTH108	os-unlink	os.unlink() should be replaced by Path.unlink()	🛠️
PTH109	os-getcwd	os.getcwd() should be replaced by Path.cwd()	🛠️
PTH110	os-path-exists	os.path.exists() should be replaced by Path.exists()	🛠️
PTH111	os-path-expanduser	os.path.expanduser() should be replaced by Path.expanduser()	🛠️
PTH112	os-path-isdir	os.path.isdir() should be replaced by Path.is_dir()	🛠️
PTH113	os-path-isfile	os.path.isfile() should be replaced by Path.is_file()	🛠️
PTH114	os-path-islink	os.path.islink() should be replaced by Path.is_symlink()	🛠️
PTH115	os-readlink	os.readlink() should be replaced by Path.readlink()	🛠️
PTH116	os-stat	os.stat() should be replaced by Path.stat(), Path.owner(), or Path.group()
PTH117	os-path-isabs	os.path.isabs() should be replaced by Path.is_absolute()	🛠️
PTH118	os-path-join	os.{module}.join() should be replaced by Path with / operator
PTH119	os-path-basename	os.path.basename() should be replaced by Path.name	🛠️
PTH120	os-path-dirname	os.path.dirname() should be replaced by Path.parent	🛠️
PTH121	os-path-samefile	os.path.samefile() should be replaced by Path.samefile()	🛠️
PTH122	os-path-splitext	os.path.splitext() should be replaced by Path.suffix, Path.stem, and Path.parent
PTH123	builtin-open	open() should be replaced by Path.open()	🛠️
PTH124	py-path	py.path is in maintenance mode, use pathlib instead
PTH201	path-constructor-current-directory	Do not pass the current directory explicitly to Path	🛠️
PTH202	os-path-getsize	os.path.getsize should be replaced by Path.stat().st_size	🛠️
PTH203	os-path-getatime	os.path.getatime should be replaced by Path.stat().st_atime	🛠️
PTH204	os-path-getmtime	os.path.getmtime should be replaced by Path.stat().st_mtime	🛠️
PTH205	os-path-getctime	os.path.getctime should be replaced by Path.stat().st_ctime	🛠️
PTH206	os-sep-split	Replace .split(os.sep) with Path.parts
PTH207	glob	Replace {function} with Path.glob or Path.rglob
PTH208	os-listdir	Use pathlib.Path.iterdir() instead.
PTH210	invalid-pathlib-with-suffix	Invalid suffix passed to .with_suffix()	🛠️
PTH211	os-symlink	os.symlink should be replaced by Path.symlink_to	🛠️

flynt (FLY)

For more, see flynt on PyPI.

Code	Name	Message
FLY002	static-join-to-f-string	Consider {expression} instead of string join	🛠️

isort (I)

For more, see isort on PyPI.

For related settings, see isort.

Code	Name	Message
I001	unsorted-imports	Import block is un-sorted or un-formatted	🛠️
I002	missing-required-import	Missing required import: {name}	🛠️

mccabe (C90)

For more, see mccabe on PyPI.

For related settings, see mccabe.

Code	Name	Message
C901	complex-structure	{name} is too complex ({complexity} > {max_complexity})

NumPy-specific rules (NPY)

Code	Name	Message
NPY001	numpy-deprecated-type-alias	Type alias np.{type_name} is deprecated, replace with builtin type	🛠️
NPY002	numpy-legacy-random	Replace legacy np.random.{method_name} call with np.random.Generator
NPY003	numpy-deprecated-function	np.{existing} is deprecated; use np.{replacement} instead	🛠️
NPY201	numpy2-deprecation	np.{existing} will be removed in NumPy 2.0. {migration_guide}	🛠️

pandas-vet (PD)

For more, see pandas-vet on PyPI.

Code	Name	Message
PD002	pandas-use-of-inplace-argument	inplace=True should be avoided; it has inconsistent behavior	🛠️
PD003	pandas-use-of-dot-is-null	.isna is preferred to .isnull; functionality is equivalent
PD004	pandas-use-of-dot-not-null	.notna is preferred to .notnull; functionality is equivalent
PD007	pandas-use-of-dot-ix	.ix is deprecated; use more explicit .loc or .iloc
PD008	pandas-use-of-dot-at	Use .loc instead of .at. If speed is important, use NumPy.
PD009	pandas-use-of-dot-iat	Use .iloc instead of .iat. If speed is important, use NumPy.
PD010	pandas-use-of-dot-pivot-or-unstack	.pivot_table is preferred to .pivot or .unstack; provides same functionality
PD011	pandas-use-of-dot-values	Use .to_numpy() instead of .values
PD012	pandas-use-of-dot-read-table	Use .read_csv instead of .read_table to read CSV files
PD013	pandas-use-of-dot-stack	.melt is preferred to .stack; provides same functionality
PD015	pandas-use-of-pd-merge	Use .merge method instead of pd.merge function. They have equivalent functionality.
PD101	pandas-nunique-constant-series-check	Using series.nunique() for checking that a series is constant is inefficient
PD901	pandas-df-variable-name	Avoid using the generic variable name df for DataFrames	❌

pep8-naming (N)

For more, see pep8-naming on PyPI.

For related settings, see pep8-naming.

Code	Name	Message
N801	invalid-class-name	Class name {name} should use CapWords convention
N802	invalid-function-name	Function name {name} should be lowercase
N803	invalid-argument-name	Argument name {name} should be lowercase
N804	invalid-first-argument-name-for-class-method	First argument of a class method should be named cls	🛠️
N805	invalid-first-argument-name-for-method	First argument of a method should be named self	🛠️
N806	non-lowercase-variable-in-function	Variable {name} in function should be lowercase
N807	dunder-function-name	Function name should not start and end with __
N811	constant-imported-as-non-constant	Constant {name} imported as non-constant {asname}
N812	lowercase-imported-as-non-lowercase	Lowercase {name} imported as non-lowercase {asname}
N813	camelcase-imported-as-lowercase	Camelcase {name} imported as lowercase {asname}
N814	camelcase-imported-as-constant	Camelcase {name} imported as constant {asname}
N815	mixed-case-variable-in-class-scope	Variable {name} in class scope should not be mixedCase
N816	mixed-case-variable-in-global-scope	Variable {name} in global scope should not be mixedCase
N817	camelcase-imported-as-acronym	CamelCase {name} imported as acronym {asname}
N818	error-suffix-on-exception-name	Exception name {name} should be named with an Error suffix
N999	invalid-module-name	Invalid module name: '{name}'

Perflint (PERF)

For more, see Perflint on PyPI.

Code	Name	Message
PERF101	unnecessary-list-cast	Do not cast an iterable to list before iterating over it	🛠️
PERF102	incorrect-dict-iterator	When using only the {subset} of a dict use the {subset}() method	🛠️
PERF203	try-except-in-loop	try-except within a loop incurs performance overhead
PERF401	manual-list-comprehension	Use {message_str} to create a transformed list	🛠️
PERF402	manual-list-copy	Use list or list.copy to create a copy of a list
PERF403	manual-dict-comprehension	Use a dictionary comprehension instead of {modifier} for-loop	🛠️

pycodestyle (E, W)

For more, see pycodestyle on PyPI.

For related settings, see pycodestyle.

Error (E)

Code	Name	Message
E101	mixed-spaces-and-tabs	Indentation contains mixed spaces and tabs
E111	indentation-with-invalid-multiple	Indentation is not a multiple of {indent_width}	🧪
E112	no-indented-block	Expected an indented block	🧪
E113	unexpected-indentation	Unexpected indentation	🧪
E114	indentation-with-invalid-multiple-comment	Indentation is not a multiple of {indent_width} (comment)	🧪
E115	no-indented-block-comment	Expected an indented block (comment)	🧪
E116	unexpected-indentation-comment	Unexpected indentation (comment)	🧪
E117	over-indented	Over-indented (comment)	🧪
E201	whitespace-after-open-bracket	Whitespace after '{symbol}'	🧪🛠️
E202	whitespace-before-close-bracket	Whitespace before '{symbol}'	🧪🛠️
E203	whitespace-before-punctuation	Whitespace before '{symbol}'	🧪🛠️
E204	whitespace-after-decorator	Whitespace after decorator	🧪🛠️
E211	whitespace-before-parameters	Whitespace before '{bracket}'	🧪🛠️
E221	multiple-spaces-before-operator	Multiple spaces before operator	🧪🛠️
E222	multiple-spaces-after-operator	Multiple spaces after operator	🧪🛠️
E223	tab-before-operator	Tab before operator	🧪🛠️
E224	tab-after-operator	Tab after operator	🧪🛠️
E225	missing-whitespace-around-operator	Missing whitespace around operator	🧪🛠️
E226	missing-whitespace-around-arithmetic-operator	Missing whitespace around arithmetic operator	🧪🛠️
E227	missing-whitespace-around-bitwise-or-shift-operator	Missing whitespace around bitwise or shift operator	🧪🛠️
E228	missing-whitespace-around-modulo-operator	Missing whitespace around modulo operator	🧪🛠️
E231	missing-whitespace	Missing whitespace after {}	🧪🛠️
E241	multiple-spaces-after-comma	Multiple spaces after comma	🧪🛠️
E242	tab-after-comma	Tab after comma	🧪🛠️
E251	unexpected-spaces-around-keyword-parameter-equals	Unexpected spaces around keyword / parameter equals	🧪🛠️
E252	missing-whitespace-around-parameter-equals	Missing whitespace around parameter equals	🧪🛠️
E261	too-few-spaces-before-inline-comment	Insert at least two spaces before an inline comment	🧪🛠️
E262	no-space-after-inline-comment	Inline comment should start with #	🧪🛠️
E265	no-space-after-block-comment	Block comment should start with #	🧪🛠️
E266	multiple-leading-hashes-for-block-comment	Too many leading # before block comment	🧪🛠️
E271	multiple-spaces-after-keyword	Multiple spaces after keyword	🧪🛠️
E272	multiple-spaces-before-keyword	Multiple spaces before keyword	🧪🛠️
E273	tab-after-keyword	Tab after keyword	🧪🛠️
E274	tab-before-keyword	Tab before keyword	🧪🛠️
E275	missing-whitespace-after-keyword	Missing whitespace after keyword	🧪🛠️
E301	blank-line-between-methods	Expected {BLANK_LINES_NESTED_LEVEL:?} blank line, found 0	🧪🛠️
E302	blank-lines-top-level	Expected {expected_blank_lines:?} blank lines, found {actual_blank_lines}	🧪🛠️
E303	too-many-blank-lines	Too many blank lines ({actual_blank_lines})	🧪🛠️
E304	blank-line-after-decorator	Blank lines found after function decorator ({lines})	🧪🛠️
E305	blank-lines-after-function-or-class	Expected 2 blank lines after class or function definition, found ({blank_lines})	🧪🛠️
E306	blank-lines-before-nested-definition	Expected 1 blank line before a nested definition, found 0	🧪🛠️
E401	multiple-imports-on-one-line	Multiple imports on one line	🛠️
E402	module-import-not-at-top-of-file	Module level import not at top of cell
E501	line-too-long	Line too long ({width} > {limit})
E502	redundant-backslash	Redundant backslash	🧪🛠️
E701	multiple-statements-on-one-line-colon	Multiple statements on one line (colon)
E702	multiple-statements-on-one-line-semicolon	Multiple statements on one line (semicolon)
E703	useless-semicolon	Statement ends with an unnecessary semicolon	🛠️
E711	none-comparison	Comparison to None should be cond is None	🛠️
E712	true-false-comparison	Avoid equality comparisons to True; use {cond}: for truth checks	🛠️
E713	not-in-test	Test for membership should be not in	🛠️
E714	not-is-test	Test for object identity should be is not	🛠️
E721	type-comparison	Use is and is not for type comparisons, or isinstance() for isinstance checks
E722	bare-except	Do not use bare except
E731	lambda-assignment	Do not assign a lambda expression, use a def	🛠️
E741	ambiguous-variable-name	Ambiguous variable name: {name}
E742	ambiguous-class-name	Ambiguous class name: {name}
E743	ambiguous-function-name	Ambiguous function name: {name}
E902	io-error	{message}
E999	syntax-error	SyntaxError	❌

Warning (W)

Code	Name	Message
W191	tab-indentation	Indentation contains tabs
W291	trailing-whitespace	Trailing whitespace	🛠️
W292	missing-newline-at-end-of-file	No newline at end of file	🛠️
W293	blank-line-with-whitespace	Blank line contains whitespace	🛠️
W391	too-many-newlines-at-end-of-file	Too many newlines at end of {domain}	🧪🛠️
W505	doc-line-too-long	Doc line too long ({width} > {limit})
W605	invalid-escape-sequence	Invalid escape sequence: \{ch}	🛠️

pydoclint (DOC)

For more, see pydoclint on PyPI.

For related settings, see pydoclint.

Code	Name	Message
DOC102	docstring-extraneous-parameter	Documented parameter {id} is not in the function's signature	🧪
DOC201	docstring-missing-returns	return is not documented in docstring	🧪
DOC202	docstring-extraneous-returns	Docstring should not have a returns section because the function doesn't return anything	🧪
DOC402	docstring-missing-yields	yield is not documented in docstring	🧪
DOC403	docstring-extraneous-yields	Docstring has a "Yields" section but the function doesn't yield anything	🧪
DOC501	docstring-missing-exception	Raised exception {id} missing from docstring	🧪
DOC502	docstring-extraneous-exception	Raised exception is not explicitly raised: {id}	🧪

pydocstyle (D)

For more, see pydocstyle on PyPI.

For related settings, see pydocstyle.

Code	Name	Message
D100	undocumented-public-module	Missing docstring in public module
D101	undocumented-public-class	Missing docstring in public class
D102	undocumented-public-method	Missing docstring in public method
D103	undocumented-public-function	Missing docstring in public function
D104	undocumented-public-package	Missing docstring in public package
D105	undocumented-magic-method	Missing docstring in magic method
D106	undocumented-public-nested-class	Missing docstring in public nested class
D107	undocumented-public-init	Missing docstring in __init__
D200	unnecessary-multiline-docstring	One-line docstring should fit on one line	🛠️
D201	blank-line-before-function	No blank lines allowed before function docstring (found {num_lines})	🛠️
D202	blank-line-after-function	No blank lines allowed after function docstring (found {num_lines})	🛠️
D203	incorrect-blank-line-before-class	1 blank line required before class docstring	🛠️
D204	incorrect-blank-line-after-class	1 blank line required after class docstring	🛠️
D205	missing-blank-line-after-summary	1 blank line required between summary line and description	🛠️
D206	docstring-tab-indentation	Docstring should be indented with spaces, not tabs
D207	under-indentation	Docstring is under-indented	🛠️
D208	over-indentation	Docstring is over-indented	🛠️
D209	new-line-after-last-paragraph	Multi-line docstring closing quotes should be on a separate line	🛠️
D210	surrounding-whitespace	No whitespaces allowed surrounding docstring text	🛠️
D211	blank-line-before-class	No blank lines allowed before class docstring	🛠️
D212	multi-line-summary-first-line	Multi-line docstring summary should start at the first line	🛠️
D213	multi-line-summary-second-line	Multi-line docstring summary should start at the second line	🛠️
D214	overindented-section	Section is over-indented ("{name}")	🛠️
D215	overindented-section-underline	Section underline is over-indented ("{name}")	🛠️
D300	triple-single-quotes	Use triple double quotes """	🛠️
D301	escape-sequence-in-docstring	Use r""" if any backslashes in a docstring	🛠️
D400	missing-trailing-period	First line should end with a period	🛠️
D401	non-imperative-mood	First line of docstring should be in imperative mood: "{first_line}"
D402	signature-in-docstring	First line should not be the function's signature
D403	first-word-uncapitalized	First word of the docstring should be capitalized: {} -> {}	🛠️
D404	docstring-starts-with-this	First word of the docstring should not be "This"
D405	non-capitalized-section-name	Section name should be properly capitalized ("{name}")	🛠️
D406	missing-new-line-after-section-name	Section name should end with a newline ("{name}")	🛠️
D407	missing-dashed-underline-after-section	Missing dashed underline after section ("{name}")	🛠️
D408	missing-section-underline-after-name	Section underline should be in the line following the section's name ("{name}")	🛠️
D409	mismatched-section-underline-length	Section underline should match the length of its name ("{name}")	🛠️
D410	no-blank-line-after-section	Missing blank line after section ("{name}")	🛠️
D411	no-blank-line-before-section	Missing blank line before section ("{name}")	🛠️
D412	blank-lines-between-header-and-content	No blank lines allowed between a section header and its content ("{name}")	🛠️
D413	missing-blank-line-after-last-section	Missing blank line after last section ("{name}")	🛠️
D414	empty-docstring-section	Section has no content ("{name}")
D415	missing-terminal-punctuation	First line should end with a period, question mark, or exclamation point	🛠️
D416	missing-section-name-colon	Section name should end with a colon ("{name}")	🛠️
D417	undocumented-param	Missing argument description in the docstring for {definition}: {name}
D418	overload-with-docstring	Function decorated with @overload shouldn't contain a docstring
D419	empty-docstring	Docstring is empty

Pyflakes (F)

For more, see Pyflakes on PyPI.

Code	Name	Message
F401	unused-import	{name} imported but unused; consider using importlib.util.find_spec to test for availability	🛠️
F402	import-shadowed-by-loop-var	Import {name} from {row} shadowed by loop variable
F403	undefined-local-with-import-star	from {name} import * used; unable to detect undefined names
F404	late-future-import	from __future__ imports must occur at the beginning of the file
F405	undefined-local-with-import-star-usage	{name} may be undefined, or defined from star imports
F406	undefined-local-with-nested-import-star-usage	from {name} import * only allowed at module level
F407	future-feature-not-defined	Future feature {name} is not defined
F501	percent-format-invalid-format	%-format string has invalid format string: {message}
F502	percent-format-expected-mapping	%-format string expected mapping but got sequence
F503	percent-format-expected-sequence	%-format string expected sequence but got mapping
F504	percent-format-extra-named-arguments	%-format string has unused named argument(s): {message}	🛠️
F505	percent-format-missing-argument	%-format string is missing argument(s) for placeholder(s): {message}
F506	percent-format-mixed-positional-and-named	%-format string has mixed positional and named placeholders
F507	percent-format-positional-count-mismatch	%-format string has {wanted} placeholder(s) but {got} substitution(s)
F508	percent-format-star-requires-sequence	%-format string * specifier requires sequence
F509	percent-format-unsupported-format-character	%-format string has unsupported format character {char}
F521	string-dot-format-invalid-format	.format call has invalid format string: {message}
F522	string-dot-format-extra-named-arguments	.format call has unused named argument(s): {message}	🛠️
F523	string-dot-format-extra-positional-arguments	.format call has unused arguments at position(s): {message}	🛠️
F524	string-dot-format-missing-arguments	.format call is missing argument(s) for placeholder(s): {message}
F525	string-dot-format-mixing-automatic	.format string mixes automatic and manual numbering
F541	f-string-missing-placeholders	f-string without any placeholders	🛠️
F601	multi-value-repeated-key-literal	Dictionary key literal {name} repeated	🛠️
F602	multi-value-repeated-key-variable	Dictionary key {name} repeated	🛠️
F621	expressions-in-star-assignment	Too many expressions in star-unpacking assignment
F622	multiple-starred-expressions	Two starred expressions in assignment
F631	assert-tuple	Assert test is a non-empty tuple, which is always True
F632	is-literal	Use == to compare constant literals	🛠️
F633	invalid-print-syntax	Use of >> is invalid with print function
F634	if-tuple	If test is a tuple, which is always True
F701	break-outside-loop	break outside loop
F702	continue-outside-loop	continue not properly in loop
F704	yield-outside-function	{keyword} statement outside of a function
F706	return-outside-function	return statement outside of a function/method
F707	default-except-not-last	An except block as not the last exception handler
F722	forward-annotation-syntax-error	Syntax error in forward annotation: {parse_error}
F811	redefined-while-unused	Redefinition of unused {name} from {row}	🛠️
F821	undefined-name	Undefined name {name}. {tip}
F822	undefined-export	Undefined name {name} in __all__
F823	undefined-local	Local variable {name} referenced before assignment
F841	unused-variable	Local variable {name} is assigned to but never used	🛠️
F842	unused-annotation	Local variable {name} is annotated but never used
F901	raise-not-implemented	raise NotImplemented should be raise NotImplementedError	🛠️

pygrep-hooks (PGH)

For more, see pygrep-hooks on GitHub.

Code	Name	Message
PGH001	eval	No builtin eval() allowed	❌
PGH002	deprecated-log-warn	warn is deprecated in favor of warning	❌🛠️
PGH003	blanket-type-ignore	Use specific rule codes when ignoring type issues
PGH004	blanket-noqa	Use specific rule codes when using noqa	🛠️
PGH005	invalid-mock-access	Mock method should be called: {name}

Pylint (PL)

For more, see Pylint on PyPI.

Convention (PLC)

Code	Name	Message
PLC0105	type-name-incorrect-variance	{kind} name "{param_name}" does not reflect its {variance}; consider renaming it to "{replacement_name}"
PLC0131	type-bivariance	{kind} cannot be both covariant and contravariant
PLC0132	type-param-name-mismatch	{kind} name {param_name} does not match assigned variable name {var_name}
PLC0205	single-string-slots	Class __slots__ should be a non-string iterable
PLC0206	dict-index-missing-items	Extracting value from dictionary without calling .items()
PLC0207	missing-maxsplit-arg	String is split more times than necessary	🛠️
PLC0208	iteration-over-set	Use a sequence type instead of a set when iterating over values	🛠️
PLC0414	useless-import-alias	Import alias does not rename original package	🛠️
PLC0415	import-outside-top-level	import should be at the top-level of a file
PLC1802	len-test	len({expression}) used as condition without comparison	🛠️
PLC1901	compare-to-empty-string	{existing} can be simplified to {replacement} as an empty string is falsey	🧪
PLC2401	non-ascii-name	{kind} name {name} contains a non-ASCII character
PLC2403	non-ascii-import-name	Module alias {name} contains a non-ASCII character
PLC2701	import-private-name	Private name import {name} from external module {module}	🧪
PLC2801	unnecessary-dunder-call	Unnecessary dunder call to {method}. {replacement}.	🧪🛠️
PLC3002	unnecessary-direct-lambda-call	Lambda expression called directly. Execute the expression inline instead.

Error (PLE)

Code	Name	Message
PLE0100	yield-in-init	__init__ method is a generator
PLE0101	return-in-init	Explicit return in __init__
PLE0115	nonlocal-and-global	Name {name} is both nonlocal and global
PLE0116	continue-in-finally	continue not supported inside finally clause
PLE0117	nonlocal-without-binding	Nonlocal name {name} found without binding
PLE0118	load-before-global-declaration	Name {name} is used prior to global declaration on {row}
PLE0237	non-slot-assignment	Attribute {name} is not defined in class's __slots__
PLE0241	duplicate-bases	Duplicate base {base} for class {class}	🛠️
PLE0302	unexpected-special-method-signature	The special method {} expects {}, {} {} given
PLE0303	invalid-length-return-type	__len__ does not return a non-negative integer
PLE0304	invalid-bool-return-type	__bool__ does not return bool	🧪
PLE0305	invalid-index-return-type	__index__ does not return an integer
PLE0307	invalid-str-return-type	__str__ does not return str
PLE0308	invalid-bytes-return-type	__bytes__ does not return bytes
PLE0309	invalid-hash-return-type	__hash__ does not return an integer
PLE0604	invalid-all-object	Invalid object in __all__, must contain only strings
PLE0605	invalid-all-format	Invalid format for __all__, must be tuple or list
PLE0643	potential-index-error	Expression is likely to raise IndexError
PLE0704	misplaced-bare-raise	Bare raise statement is not inside an exception handler
PLE1132	repeated-keyword-argument	Repeated keyword argument: {duplicate_keyword}
PLE1141	dict-iter-missing-items	Unpacking a dictionary in iteration without calling .items()	🧪🛠️
PLE1142	await-outside-async	await should be used within an async function
PLE1205	logging-too-many-args	Too many arguments for logging format string
PLE1206	logging-too-few-args	Not enough arguments for logging format string
PLE1300	bad-string-format-character	Unsupported format character '{format_char}'
PLE1307	bad-string-format-type	Format type does not match argument type
PLE1310	bad-str-strip-call	String {strip} call contains duplicate characters (did you mean {removal}?)
PLE1507	invalid-envvar-value	Invalid type for initial os.getenv argument; expected str
PLE1519	singledispatch-method	@singledispatch decorator should not be used on methods	🛠️
PLE1520	singledispatchmethod-function	@singledispatchmethod decorator should not be used on non-method functions	🛠️
PLE1700	yield-from-in-async-function	yield from statement in async function; use async for instead
PLE2502	bidirectional-unicode	Contains control characters that can permit obfuscated code
PLE2510	invalid-character-backspace	Invalid unescaped character backspace, use "\b" instead	🛠️
PLE2512	invalid-character-sub	Invalid unescaped character SUB, use "\x1a" instead	🛠️
PLE2513	invalid-character-esc	Invalid unescaped character ESC, use "\x1b" instead	🛠️
PLE2514	invalid-character-nul	Invalid unescaped character NUL, use "\0" instead	🛠️
PLE2515	invalid-character-zero-width-space	Invalid unescaped character zero-width-space, use "\u200B" instead	🛠️
PLE4703	modified-iterating-set	Iterated set {name} is modified within the for loop	🧪🛠️

Refactor (PLR)

Code	Name	Message
PLR0124	comparison-with-itself	Name compared with itself, consider replacing {actual}
PLR0133	comparison-of-constant	Two constants compared in a comparison, consider replacing {left_constant} {op} {right_constant}
PLR0202	no-classmethod-decorator	Class method defined without decorator	🧪🛠️
PLR0203	no-staticmethod-decorator	Static method defined without decorator	🧪🛠️
PLR0206	property-with-parameters	Cannot have defined parameters for properties
PLR0402	manual-from-import	Use from {module} import {name} in lieu of alias	🛠️
PLR0904	too-many-public-methods	Too many public methods ({methods} > {max_methods})	🧪
PLR0911	too-many-return-statements	Too many return statements ({returns} > {max_returns})
PLR0912	too-many-branches	Too many branches ({branches} > {max_branches})
PLR0913	too-many-arguments	Too many arguments in function definition ({c_args} > {max_args})
PLR0914	too-many-locals	Too many local variables ({current_amount}/{max_amount})	🧪
PLR0915	too-many-statements	Too many statements ({statements} > {max_statements})
PLR0916	too-many-boolean-expressions	Too many Boolean expressions ({expressions} > {max_expressions})	🧪
PLR0917	too-many-positional-arguments	Too many positional arguments ({c_pos}/{max_pos})	🧪
PLR1701	repeated-isinstance-calls	Merge isinstance calls: {expression}	❌🛠️
PLR1702	too-many-nested-blocks	Too many nested blocks ({nested_blocks} > {max_nested_blocks})	🧪
PLR1704	redefined-argument-from-local	Redefining argument with the local name {name}
PLR1706	and-or-ternary	Consider using if-else expression	❌
PLR1708	stop-iteration-return	Explicit raise StopIteration in generator	🧪
PLR1711	useless-return	Useless return statement at end of function	🛠️
PLR1714	repeated-equality-comparison	Consider merging multiple comparisons: {expression}. Use a set if the elements are hashable.	🛠️
PLR1716	boolean-chained-comparison	Contains chained boolean comparison that can be simplified	🛠️
PLR1722	sys-exit-alias	Use sys.exit() instead of {name}	🛠️
PLR1730	if-stmt-min-max	Replace if statement with {replacement}	🛠️
PLR1733	unnecessary-dict-index-lookup	Unnecessary lookup of dictionary value by key	🛠️
PLR1736	unnecessary-list-index-lookup	List index lookup in enumerate() loop	🛠️
PLR2004	magic-value-comparison	Magic value used in comparison, consider replacing {value} with a constant variable
PLR2044	empty-comment	Line with empty comment	🛠️
PLR5501	collapsible-else-if	Use elif instead of else then if, to reduce indentation	🛠️
PLR6104	non-augmented-assignment	Use {operator} to perform an augmented assignment directly	🧪🛠️
PLR6201	literal-membership	Use a set literal when testing for membership	🧪🛠️
PLR6301	no-self-use	Method {method_name} could be a function, class method, or static method	🧪

Warning (PLW)

Code	Name	Message
PLW0108	unnecessary-lambda	Lambda may be unnecessary; consider inlining inner function	🛠️
PLW0120	useless-else-on-loop	else clause on loop without a break statement; remove the else and dedent its contents	🛠️
PLW0127	self-assigning-variable	Self-assignment of variable {name}
PLW0128	redeclared-assigned-name	Redeclared variable {name} in assignment
PLW0129	assert-on-string-literal	Asserting on an empty string literal will never pass
PLW0131	named-expr-without-context	Named expression used without context
PLW0133	useless-exception-statement	Missing raise statement on exception	🛠️
PLW0177	nan-comparison	Comparing against a NaN value; use math.isnan instead
PLW0211	bad-staticmethod-argument	First argument of a static method should not be named {argument_name}
PLW0244	redefined-slots-in-subclass	Slot {slot_name} redefined from base class {base}	🧪
PLW0245	super-without-brackets	super call is missing parentheses	🛠️
PLW0406	import-self	Module {name} imports itself
PLW0602	global-variable-not-assigned	Using global for {name} but no assignment is done
PLW0603	global-statement	Using the global statement to update {name} is discouraged
PLW0604	global-at-module-level	global at module level is redundant
PLW0642	self-or-cls-assignment	Reassigned {} variable in {method_type} method
PLW0711	binary-op-exception	Exception to catch is the result of a binary and operation
PLW1501	bad-open-mode	{mode} is not a valid mode for open
PLW1507	shallow-copy-environ	Shallow copy of os.environ via copy.copy(os.environ)	🛠️
PLW1508	invalid-envvar-default	Invalid type for environment variable default; expected str or None
PLW1509	subprocess-popen-preexec-fn	preexec_fn argument is unsafe when using threads
PLW1510	subprocess-run-without-check	subprocess.run without explicit check argument	🛠️
PLW1514	unspecified-encoding	{function_name} in text mode without explicit encoding argument	🧪🛠️
PLW1641	eq-without-hash	Object does not implement __hash__ method
PLW2101	useless-with-lock	Threading lock directly created in with statement has no effect
PLW2901	redefined-loop-name	Outer {outer_kind} variable {name} overwritten by inner {inner_kind} target
PLW3201	bad-dunder-method-name	Dunder method {name} has no special meaning in Python 3	🧪
PLW3301	nested-min-max	Nested {func} calls can be flattened	🛠️

pyupgrade (UP)

For more, see pyupgrade on PyPI.

For related settings, see pyupgrade.

Code	Name	Message
UP001	useless-metaclass-type	__metaclass__ = type is implied	🛠️
UP003	type-of-primitive	Use {} instead of type(...)	🛠️
UP004	useless-object-inheritance	Class {name} inherits from object	🛠️
UP005	deprecated-unittest-alias	{alias} is deprecated, use {target}	🛠️
UP006	non-pep585-annotation	Use {to} instead of {from} for type annotation	🛠️
UP007	non-pep604-annotation-union	Use X | Y for type annotations	🛠️
UP008	super-call-with-parameters	Use super() instead of super(__class__, self)	🛠️
UP009	utf8-encoding-declaration	UTF-8 encoding declaration is unnecessary	🛠️
UP010	unnecessary-future-import	Unnecessary __future__ import {import} for target Python version	🛠️
UP011	lru-cache-without-parameters	Unnecessary parentheses to functools.lru_cache	🛠️
UP012	unnecessary-encode-utf8	Unnecessary call to encode as UTF-8	🛠️
UP013	convert-typed-dict-functional-to-class	Convert {name} from TypedDict functional to class syntax	🛠️
UP014	convert-named-tuple-functional-to-class	Convert {name} from NamedTuple functional to class syntax	🛠️
UP015	redundant-open-modes	Unnecessary mode argument	🛠️
UP017	datetime-timezone-utc	Use datetime.UTC alias	🛠️
UP018	native-literals	Unnecessary {literal_type} call (rewrite as a literal)	🛠️
UP019	typing-text-str-alias	{}.Text is deprecated, use str	🛠️
UP020	open-alias	Use builtin open	🛠️
UP021	replace-universal-newlines	universal_newlines is deprecated, use text	🛠️
UP022	replace-stdout-stderr	Prefer capture_output over sending stdout and stderr to PIPE	🛠️
UP023	deprecated-c-element-tree	cElementTree is deprecated, use ElementTree	🛠️
UP024	os-error-alias	Replace aliased errors with OSError	🛠️
UP025	unicode-kind-prefix	Remove unicode literals from strings	🛠️
UP026	deprecated-mock-import	mock is deprecated, use unittest.mock	🛠️
UP027	unpacked-list-comprehension	Replace unpacked list comprehension with a generator expression	❌
UP028	yield-in-for-loop	Replace yield over for loop with yield from	🛠️
UP029	unnecessary-builtin-import	Unnecessary builtin import: {import}	🛠️
UP030	format-literals	Use implicit references for positional format fields	🛠️
UP031	printf-string-formatting	Use format specifiers instead of percent format	🛠️
UP032	f-string	Use f-string instead of format call	🛠️
UP033	lru-cache-with-maxsize-none	Use @functools.cache instead of @functools.lru_cache(maxsize=None)	🛠️
UP034	extraneous-parentheses	Avoid extraneous parentheses	🛠️
UP035	deprecated-import	Import from {target} instead: {names}	🛠️
UP036	outdated-version-block	Version block is outdated for minimum Python version	🛠️
UP037	quoted-annotation	Remove quotes from type annotation	🛠️
UP038	non-pep604-isinstance	Use X | Y in {} call instead of (X, Y)	❌🛠️
UP039	unnecessary-class-parentheses	Unnecessary parentheses after class definition	🛠️
UP040	non-pep695-type-alias	Type alias {name} uses {type_alias_method} instead of the type keyword	🛠️
UP041	timeout-error-alias	Replace aliased errors with TimeoutError	🛠️
UP042	replace-str-enum	Class {name} inherits from both str and enum.Enum	🛠️
UP043	unnecessary-default-type-args	Unnecessary default type arguments	🛠️
UP044	non-pep646-unpack	Use * for unpacking	🛠️
UP045	non-pep604-annotation-optional	Use X | None for type annotations	🛠️
UP046	non-pep695-generic-class	Generic class {name} uses Generic subclass instead of type parameters	🛠️
UP047	non-pep695-generic-function	Generic function {name} should use type parameters	🛠️
UP049	private-type-parameter	Generic {} uses private type parameters	🛠️
UP050	useless-class-metaclass-type	Class {name} uses metaclass=type, which is redundant	🛠️

refurb (FURB)

For more, see refurb on PyPI.

Code	Name	Message
FURB101	read-whole-file	Path.open() followed by read() can be replaced by {filename}.{suggestion}	🧪🛠️
FURB103	write-whole-file	Path.open() followed by write() can be replaced by {filename}.{suggestion}	🧪🛠️
FURB105	print-empty-string	Unnecessary empty string passed to print	🛠️
FURB110	if-exp-instead-of-or-operator	Replace ternary if expression with or operator	🛠️
FURB113	repeated-append	Use {suggestion} instead of repeatedly calling {name}.append()	🧪🛠️
FURB116	f-string-number-format	Replace {function_name} call with {display}	🛠️
FURB118	reimplemented-operator	Use operator.{operator} instead of defining a {target}	🧪🛠️
FURB122	for-loop-writes	Use of {}.write in a for loop	🛠️
FURB129	readlines-in-for	Instead of calling readlines(), iterate over file object directly	🛠️
FURB131	delete-full-slice	Prefer clear over deleting a full slice	🧪🛠️
FURB132	check-and-remove-from-set	Use {suggestion} instead of check and remove	🛠️
FURB136	if-expr-min-max	Replace if expression with {min_max} call	🛠️
FURB140	reimplemented-starmap	Use itertools.starmap instead of the generator	🧪🛠️
FURB142	for-loop-set-mutations	Use of set.{}() in a for loop	🧪🛠️
FURB145	slice-copy	Prefer copy method over slicing	🧪🛠️
FURB148	unnecessary-enumerate	enumerate value is unused, use for x in range(len(y)) instead	🧪🛠️
FURB152	math-constant	Replace {literal} with math.{constant}	🧪🛠️
FURB154	repeated-global	Use of repeated consecutive {}	🧪🛠️
FURB156	hardcoded-string-charset	Use of hardcoded string charset	🧪🛠️
FURB157	verbose-decimal-constructor	Verbose expression in Decimal constructor	🛠️
FURB161	bit-count	Use of bin({existing}).count('1')	🛠️
FURB162	fromisoformat-replace-z	Unnecessary timezone replacement with zero offset	🛠️
FURB163	redundant-log-base	Prefer math.{log_function}({arg}) over math.log with a redundant base	🛠️
FURB164	unnecessary-from-float	Verbose method {method_name} in {constructor} construction	🧪🛠️
FURB166	int-on-sliced-str	Use of int with explicit base={base} after removing prefix	🛠️
FURB167	regex-flag-alias	Use of regular expression alias re.{}	🛠️
FURB168	isinstance-type-none	Prefer is operator over isinstance to check if an object is None	🛠️
FURB169	type-none-comparison	When checking against None, use {} instead of comparison with type(None)	🛠️
FURB171	single-item-membership-test	Membership test against single-item container	🛠️
FURB177	implicit-cwd	Prefer Path.cwd() over Path().resolve() for current-directory lookups	🛠️
FURB180	meta-class-abc-meta	Use of metaclass=abc.ABCMeta to define abstract base class	🧪🛠️
FURB181	hashlib-digest-hex	Use of hashlib's .digest().hex()	🛠️
FURB187	list-reverse-copy	Use of assignment of reversed on list {name}	🛠️
FURB188	slice-to-remove-prefix-or-suffix	Prefer str.removeprefix() over conditionally replacing with slice.	🛠️
FURB189	subclass-builtin	Subclassing {subclass} can be error prone, use collections.{replacement} instead	🧪🛠️
FURB192	sorted-min-max	Prefer min over sorted() to compute the minimum value in a sequence	🧪🛠️

Ruff-specific rules (RUF)

Code	Name	Message
RUF001	ambiguous-unicode-character-string	String contains ambiguous {}. Did you mean {}?
RUF002	ambiguous-unicode-character-docstring	Docstring contains ambiguous {}. Did you mean {}?
RUF003	ambiguous-unicode-character-comment	Comment contains ambiguous {}. Did you mean {}?
RUF005	collection-literal-concatenation	Consider {expression} instead of concatenation	🛠️
RUF006	asyncio-dangling-task	Store a reference to the return value of {expr}.{method}
RUF007	zip-instead-of-pairwise	Prefer itertools.pairwise() over zip() when iterating over successive pairs	🛠️
RUF008	mutable-dataclass-default	Do not use mutable default values for dataclass attributes
RUF009	function-call-in-dataclass-default-argument	Do not perform function call {name} in dataclass defaults
RUF010	explicit-f-string-type-conversion	Use explicit conversion flag	🛠️
RUF011	ruff-static-key-dict-comprehension	Dictionary comprehension uses static key	❌
RUF012	mutable-class-default	Mutable default value for class attribute
RUF013	implicit-optional	PEP 484 prohibits implicit Optional	🛠️
RUF015	unnecessary-iterable-allocation-for-first-element	Prefer next({iterable}) over single element slice	🛠️
RUF016	invalid-index-type	Slice in indexed access to type {value_type} uses type {index_type} instead of an integer
RUF017	quadratic-list-summation	Avoid quadratic list summation	🛠️
RUF018	assignment-in-assert	Avoid assignment expressions in assert statements
RUF019	unnecessary-key-check	Unnecessary key check before dictionary access	🛠️
RUF020	never-union	{never_like} | T is equivalent to T	🛠️
RUF021	parenthesize-chained-operators	Parenthesize a and b expressions when chaining and and or together, to make the precedence clear	🛠️
RUF022	unsorted-dunder-all	__all__ is not sorted	🛠️
RUF023	unsorted-dunder-slots	{}.__slots__ is not sorted	🛠️
RUF024	mutable-fromkeys-value	Do not pass mutable objects as values to dict.fromkeys	🛠️
RUF026	default-factory-kwarg	default_factory is a positional-only argument to defaultdict	🛠️
RUF027	missing-f-string-syntax	Possible f-string without an f prefix	🧪🛠️
RUF028	invalid-formatter-suppression-comment	This suppression comment is invalid because {}	🛠️
RUF029	unused-async	Function {name} is declared async, but doesn't await or use async features.	🧪
RUF030	assert-with-print-message	print() call in assert statement is likely unintentional	🛠️
RUF031	incorrectly-parenthesized-tuple-in-subscript	Use parentheses for tuples in subscripts	🧪🛠️
RUF032	decimal-from-float-literal	Decimal() called with float literal argument	🛠️
RUF033	post-init-default	__post_init__ method with argument defaults	🛠️
RUF034	useless-if-else	Useless if-else condition
RUF035	ruff-unsafe-markup-use	Unsafe use of {name} detected	❌
RUF036	none-not-at-end-of-union	None not at the end of the type annotation.	🧪
RUF037	unnecessary-empty-iterable-within-deque-call	Unnecessary empty iterable within a deque call	🛠️
RUF038	redundant-bool-literal	Literal[True, False, ...] can be replaced with Literal[...] | bool	🧪🛠️
RUF039	unraw-re-pattern	First argument to {call} is not raw string	🧪🛠️
RUF040	invalid-assert-message-literal-argument	Non-string literal used as assert message
RUF041	unnecessary-nested-literal	Unnecessary nested Literal	🛠️
RUF043	pytest-raises-ambiguous-pattern	Pattern passed to match= contains metacharacters but is neither escaped nor raw
RUF045	implicit-class-var-in-dataclass	Assignment without annotation found in dataclass body	🧪
RUF046	unnecessary-cast-to-int	Value being cast to int is already an integer	🛠️
RUF047	needless-else	Empty else clause	🧪🛠️
RUF048	map-int-version-parsing	__version__ may contain non-integral-like elements
RUF049	dataclass-enum	An enum class should not be decorated with @dataclass
RUF051	if-key-in-dict-del	Use pop instead of key in dict followed by del dict[key]	🛠️
RUF052	used-dummy-variable	Local dummy variable {} is accessed	🧪🛠️
RUF053	class-with-mixed-type-vars	Class with type parameter list inherits from Generic	🛠️
RUF054	indented-form-feed	Indented form feed	🧪
RUF055	unnecessary-regular-expression	Plain string pattern passed to re function	🧪🛠️
RUF056	falsy-dict-get-fallback	Avoid providing a falsy fallback to dict.get() in boolean test positions. The default fallback None is already falsy.	🧪🛠️
RUF057	unnecessary-round	Value being rounded is already an integer	🛠️
RUF058	starmap-zip	itertools.starmap called on zip iterable	🛠️
RUF059	unused-unpacked-variable	Unpacked variable {name} is never used	🛠️
RUF060	in-empty-collection	Unnecessary membership test on empty collection
RUF061	legacy-form-pytest-raises	Use context-manager form of pytest.{}()	🛠️
RUF063	access-annotations-from-class-dict	Use {suggestion} instead of __dict__ access	🧪
RUF064	non-octal-permissions	Non-octal mode	🛠️
RUF065	logging-eager-conversion	Unnecessary oct() conversion when formatting with %s. Use %#o instead of %s	🧪
RUF066	property-without-return	{name} is a property without a return statement	🧪
RUF067	non-empty-init-module	__init__ module should not contain any code	🧪
RUF068	duplicate-entry-in-dunder-all	__all__ contains duplicate entries	🧪🛠️
RUF069	float-equality-comparison	Unreliable floating point equality comparison {left} {operator} {right}	🧪
RUF100	unused-noqa	Unused {}	🛠️
RUF101	redirected-noqa	{original} is a redirect to {target}	🛠️
RUF102	invalid-rule-code	Invalid rule code in {}: {}	🛠️
RUF103	invalid-suppression-comment	Invalid suppression comment: {msg}	🛠️
RUF104	unmatched-suppression-comment	Suppression comment without matching #ruff:enable comment
RUF200	invalid-pyproject-toml	Failed to parse pyproject.toml: {message}

tryceratops (TRY)

For more, see tryceratops on PyPI.

Code	Name	Message
TRY002	raise-vanilla-class	Create your own exception
TRY003	raise-vanilla-args	Avoid specifying long messages outside the exception class
TRY004	type-check-without-type-error	Prefer TypeError exception for invalid type
TRY200	reraise-no-cause	Use raise from to specify exception cause	❌
TRY201	verbose-raise	Use raise without specifying exception name	🛠️
TRY203	useless-try-except	Remove exception handler; error is immediately re-raised
TRY300	try-consider-else	Consider moving this statement to an else block
TRY301	raise-within-try	Abstract raise to an inner function
TRY400	error-instead-of-exception	Use logging.exception instead of logging.error	🛠️
TRY401	verbose-log-message	Redundant exception object included in logging.exception call