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Rules

Ruff supports over 800 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.

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;
🛠️
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.
🛠️

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
🛠️

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 is resolved before function call; consider _("string %s") % arg
INT002 format-in-get-text-func-call format method argument is resolved before function call; consider _("string %s") % arg
INT003 printf-in-get-text-func-call printf-style format is resolved before function call; consider _("string %s") % arg

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
🛠️

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 Replace with {suggested_split_type}(..., maxsplit=1).
🧪🛠️
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 open and read should be replaced by Path({filename}).{suggestion}
🧪🛠️
FURB103 write-whole-file open and write should be replaced by Path({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 class attributes should be annotated with typing.ClassVar
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
🧪
RUF100 unused-noqa Unused noqa directive
🛠️
RUF101 redirected-noqa {original} is a redirect to {target}
🛠️
RUF102 invalid-rule-code Invalid rule code in # noqa: {}
🧪🛠️
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