Add additional checks for match class patterns #10587

cdce8p · 2025-09-24T20:25:24Z

Description

Followup to #10559

Add additional checks for match class patterns.

match-class-bind-self
match-class-positional-attributes

codecov · 2025-09-24T20:56:46Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.95%. Comparing base (68ab16f) to head (f420f28).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10587   +/-   ##
=======================================
  Coverage   95.95%   95.95%           
=======================================
  Files         176      176           
  Lines       19455    19469   +14     
=======================================
+ Hits        18668    18682   +14     
  Misses        787      787

Files with missing lines	Coverage Δ
pylint/checkers/match_statements_checker.py	`100.00% <100.00%> (ø)`

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cdce8p · 2025-09-24T22:09:30Z

pylint/checkers/match_statements_checker.py

+                inferred = safe_infer(node.cls)
+                if not (
+                    isinstance(inferred, nodes.ClassDef)
+                    and inferred.qname() in MATCH_CLASS_SELF_NAMES
+                ):
+                    self.add_message(
+                        "match-class-positional-attributes",
+                        node=node,
+                        confidence=HIGH,
+                    )


Looking at the sentry results, I do wonder if this is to strict and we'd end up emitting too many false positives. self matches also work for every subclass of the special builtin classes (as long as they don't implement __match_args__). Most notably NamedTuple.

Added some special casing for tuple that should handle it.

pylint/checkers/match_statements_checker.py

Pierre-Sassoulas · 2025-09-25T04:04:28Z

pylint/checkers/match_statements_checker.py

+            "can be avoided.",
+        ),
+        "R1906": (
+            "Use keyword attributes instead of positional ones",


Suggested change

"Use keyword attributes instead of positional ones",

"Use keyword attributes instead of positional ones ('%s')",

I think we can construct the expected here too. (And one day use it to autofix?)

pylint/checkers/match_statements_checker.py

Pierre-Sassoulas · 2025-09-25T04:06:04Z

tests/functional/ext/mccabe/mccabe.py

        case {"type": "user", "data": user_data}:
            match user_data:  # Nested match adds complexity
-                case {"name": str(name)}:
+                case {"name": str() as name}:


This check already making pylint better 😄

Fixed most of the pylint code in #10580 already. That's why there are "only" two instances in a test case left here.

github-actions · 2025-09-25T11:32:56Z

🤖 According to the primer, this change has no effect on the checked open source code. 🤖🎉

This comment was generated for commit f420f28

Pierre-Sassoulas · 2025-09-26T07:07:22Z

pylint/checkers/match_statements_checker.py

            "attribute in a class pattern.",
        ),
+        "R1905": (
+            "Use '%s() as %s' instead",


Suggested change

"Use '%s() as %s' instead",

"Use '%s() as %s' instead, if performance is a concern",

(This is a suggestion, the message is short, there's room for explanation in it, maybe ?)

Seems Daniel merged it before I saw your comment 😄
Anyway, not sure we need an extra comment here. I did think about moving these checks to an extension (e.g. CodeStyle. However, there are clear performance benefits which is why I decided to keep them always enabled.

If we get reports about them, we could still consider amending the message or moving the check.

Oops, sorry! I saw Pierre's approval and thought it was a comment from his earlier review.

Will be more careful next time!

No problem, it was good to merge which is why I approved in the first place 😄

Pierre-Sassoulas

LGTM, great checker !

nickdrozd · 2025-10-12T19:05:16Z

Just got a match-class-bind-self warning. It's a nice one, I didn't know about int() as x syntax.

The "What's New" page links to the wrong PR.

cdce8p · 2025-10-12T19:17:22Z

The "What's New" page links to the wrong PR.

Thanks for the hint @nickdrozd. Opened #10644 to fix it. Also changed the Github release docs.

This PR contains the following updates: | Package | Change | Age | Confidence | |---|---|---|---| | [pylint](https://github.com/pylint-dev/pylint) ([changelog](https://pylint.readthedocs.io/en/latest/whatsnew/3/)) | `<4.0.0,>=3.3.3` -> `<4.1.0,>=4.0.0` | [![age](https://developer.mend.io/api/mc/badges/age/pypi/pylint/4.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/pylint/3.3.9/4.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | --- ### Release Notes <details> <summary>pylint-dev/pylint (pylint)</summary> ### [`v4.0.0`](https://github.com/pylint-dev/pylint/releases/tag/v4.0.0) [Compare Source](pylint-dev/pylint@v3.3.9...v4.0.0) - Pylint now supports Python 3.14. - Pylint's inference engine (`astroid`) is now much more precise, understanding implicit booleanness and ternary expressions. (Thanks [@zenlyj](https://github.com/zenlyj)!) Consider this example: ```python class Result: errors: dict | None = None result = Result() if result.errors: result.errors[field_key] ### inference engine understands result.errors cannot be None ### pylint no longer raises unsubscriptable-object ``` The required `astroid` version is now 4.0.0. See the [astroid changelog](https://pylint.readthedocs.io/projects/astroid/en/latest/changelog.html#what-s-new-in-astroid-4-0-0) for additional fixes, features, and performance improvements applicable to pylint. - Handling of `invalid-name` at the module level was patchy. Now, module-level constants that are reassigned are treated as variables and checked against `--variable-rgx` rather than `--const-rgx`. Module-level lists, sets, and objects can pass against either regex. Here, `LIMIT` is reassigned, so pylint only uses `--variable-rgx`: ```python LIMIT = 500 # [invalid-name] if sometimes: LIMIT = 1 # [invalid-name] ``` If this is undesired, refactor using *exclusive* assignment so that it is evident that this assignment happens only once: ```python if sometimes: LIMIT = 1 else: LIMIT = 500 # exclusive assignment: uses const regex, no warning ``` Lists, sets, and objects still pass against either `const-rgx` or `variable-rgx` even if reassigned, but are no longer completely skipped: ```python MY_LIST = [] my_list = [] My_List = [] # [invalid-name] ``` Remember to adjust the [regexes](https://pylint.readthedocs.io/en/latest/user_guide/messages/convention/invalid-name.html) and [allow lists](https://pylint.readthedocs.io/en/latest/user_guide/configuration/all-options.html#good-names) to your liking. ## Breaking Changes - `invalid-name` now distinguishes module-level constants that are assigned only once from those that are reassigned and now applies `--variable-rgx` to the latter. Values other than literals (lists, sets, objects) can pass against either the constant or variable regexes (e.g. "LOGGER" or "logger" but not "LoGgEr"). Remember that `--good-names` or `--good-names-rgxs` can be provided to explicitly allow good names. Closes [#3585](pylint-dev/pylint#3585) - The unused `pylintrc` argument to `PyLinter.__init__()` is deprecated and will be removed. Refs [#6052](pylint-dev/pylint#6052) - Commented out code blocks such as `# bar() # TODO: remove dead code` will no longer emit `fixme`. Refs [#9255](pylint-dev/pylint#9255) - `pyreverse` `Run` was changed to no longer call `sys.exit()` in its `__init__`. You should now call `Run(args).run()` which will return the exit code instead. Having a class that always raised a `SystemExit` exception was considered a bug. Normal usage of pyreverse through the CLI will not be affected by this change. Refs [#9689](pylint-dev/pylint#9689) - The `suggestion-mode` option was removed, as pylint now always emits user-friendly hints instead of false-positive error messages. You should remove it from your conf if it's defined. Refs [#9962](pylint-dev/pylint#9962) - The `async.py` checker module has been renamed to `async_checker.py` since `async` is a Python keyword and cannot be imported directly. This allows for better testing and extensibility of the async checker functionality. Refs [#10071](pylint-dev/pylint#10071) - The message-id of `continue-in-finally` was changed from `E0116` to `W0136`. The warning is now emitted for every Python version since it will raise a syntax warning in Python 3.14. See [PEP 765 - Disallow return/break/continue that exit a finally block](https://peps.python.org/pep-0765/). Refs [#10480](pylint-dev/pylint#10480) - Removed support for `nmp.NaN` alias for `numpy.NaN` being recognized in ':ref:`nan-comparison`'. Use `np` or `numpy` instead. Refs [#10583](pylint-dev/pylint#10583) - Version requirement for `isort` has been bumped to >=5.0.0. The internal compatibility for older `isort` versions exposed via `pylint.utils.IsortDriver` has been removed. Refs [#10637](pylint-dev/pylint#10637) ## New Features - `comparison-of-constants` now uses the unicode from the ast instead of reformatting from the node's values preventing some bad formatting due to `utf-8` limitation. The message now uses `"` instead of `'` to better work with what the python ast returns. Refs [#8736](pylint-dev/pylint#8736) - Enhanced pyreverse to properly distinguish between UML relationship types (association, aggregation, composition) based on object ownership semantics. Type annotations without assignment are now treated as associations, parameter assignments as aggregations, and object instantiation as compositions. Closes [#9045](pylint-dev/pylint#9045) Closes [#9267](pylint-dev/pylint#9267) - The `fixme` check can now search through docstrings as well as comments, by using `check-fixme-in-docstring = true` in the `[tool.pylint.miscellaneous]` section. Closes [#9255](pylint-dev/pylint#9255) - The `use-implicit-booleaness-not-x` checks now distinguish between comparisons used in boolean contexts and those that are not, enabling them to provide more accurate refactoring suggestions. Closes [#9353](pylint-dev/pylint#9353) - The verbose option now outputs the filenames of the files that have been checked. Previously, it only included the number of checked and skipped files. Closes [#9357](pylint-dev/pylint#9357) - colorized reporter now colorizes messages/categories that have been configured as `fail-on` in red inverse. This makes it easier to quickly find the errors that are causing pylint CI job failures. Closes [#9898](pylint-dev/pylint#9898) - Enhanced support for [@property](https://github.com/property) decorator in pyreverse to correctly display return types of annotated properties when generating class diagrams. Closes [#10057](pylint-dev/pylint#10057) - Add --max-depth option to pyreverse to control diagram complexity. A depth of 0 shows only top-level packages, 1 shows one level of subpackages, etc. This helps manage visualization of large codebases by limiting the depth of displayed packages and classes. Refs [#10077](pylint-dev/pylint#10077) - Handle deferred evaluation of annotations in Python 3.14. Closes [#10149](pylint-dev/pylint#10149) - Enhanced pyreverse to properly detect aggregations for comprehensions (list, dict, set, generator). Closes [#10236](pylint-dev/pylint#10236) - `pyreverse`: add support for colorized output when using output format `mmd` (MermaidJS) and `html`. Closes [#10242](pylint-dev/pylint#10242) - pypy 3.11 is now officially supported. Refs [#10287](pylint-dev/pylint#10287) - Add support for Python 3.14. Refs [#10467](pylint-dev/pylint#10467) - Add naming styles for `ParamSpec` and `TypeVarTuple` that align with the `TypeVar` style. Refs [#10541](pylint-dev/pylint#10541) ## New Checks - Add `match-statements` checker and the following message: `bare-name-capture-pattern`. This will emit an error message when a name capture pattern is used in a match statement which would make the remaining patterns unreachable. This code is a SyntaxError at runtime. Closes [#7128](pylint-dev/pylint#7128) - Add new check `async-context-manager-with-regular-with` to detect async context managers used with regular `with` statements instead of `async with`. Refs [#10408](pylint-dev/pylint#10408) - Add `break-in-finally` warning. Using `break` inside the `finally` clause will raise a syntax warning in Python 3.14. See `PEP 765 - Disallow return/break/continue that exit a finally block <https://peps.python.org/pep-0765/>`\_. Refs [#10480](pylint-dev/pylint#10480) - Add new checks for invalid uses of class patterns in :keyword:`match`. - :ref:`invalid-match-args-definition` is emitted if :py:data:`object.__match_args__` isn't a tuple of strings. - :ref:`too-many-positional-sub-patterns` if there are more positional sub-patterns than specified in :py:data:`object.__match_args__`. - :ref:`multiple-class-sub-patterns` if there are multiple sub-patterns for the same attribute. Refs [#10559](pylint-dev/pylint#10559) - Add additional checks for suboptimal uses of class patterns in :keyword:`match`. - :ref:`match-class-bind-self` is emitted if a name is bound to `self` instead of using an `as` pattern. - :ref:`match-class-positional-attributes` is emitted if a class pattern has positional attributes when keywords could be used. Refs [#10587](pylint-dev/pylint#10587) - Add a `consider-math-not-float` message. `float("nan")` and `float("inf")` are slower than their counterpart `math.inf` and `math.nan` by a factor of 4 (notwithstanding the initial import of math) and they are also not well typed when using mypy. This check also catches typos in float calls as a side effect. The :ref:`pylint.extensions.code_style` need to be activated for this check to work. Refs [#10621](pylint-dev/pylint#10621) ## False Positives Fixed - Fix a false positive for `used-before-assignment` when a variable defined under an `if` and via a named expression (walrus operator) is used later when guarded under the same `if` test. Closes [#10061](pylint-dev/pylint#10061) - Fix :ref:`no-name-in-module` for members of `concurrent.futures` with Python 3.14. Closes [#10632](pylint-dev/pylint#10632) ## False Negatives Fixed - Fix false negative for `used-before-assignment` when a `TYPE_CHECKING` import is used as a type annotation prior to erroneous usage. Refs [#8893](pylint-dev/pylint#8893) - Match cases are now counted as edges in the McCabe graph and will increase the complexity accordingly. Refs [#9667](pylint-dev/pylint#9667) - Check module-level constants with type annotations for `invalid-name`. Remember to adjust `const-naming-style` or `const-rgx` to your liking. Closes [#9770](pylint-dev/pylint#9770) - Fix false negative where function-redefined (E0102) was not reported for functions with a leading underscore. Closes [#9894](pylint-dev/pylint#9894) - We now raise a `logging-too-few-args` for format string with no interpolation arguments at all (i.e. for something like `logging.debug("Awaiting process %s")` or `logging.debug("Awaiting process {pid}")`). Previously we did not raise for such case. Closes [#9999](pylint-dev/pylint#9999) - Fix false negative for `used-before-assignment` when a function is defined inside a `TYPE_CHECKING` guard block and used later. Closes [#10028](pylint-dev/pylint#10028) - Fix a false negative for `possibly-used-before-assignment` when a variable is conditionally defined and later assigned to a type-annotated variable. Closes [#10421](pylint-dev/pylint#10421) - Fix false negative for `deprecated-module` when a `__import__` method is used instead of `import` sentence. Refs [#10453](pylint-dev/pylint#10453) - Count match cases for `too-many-branches` check. Refs [#10542](pylint-dev/pylint#10542) - Fix false-negative where :ref:`unused-import` was not reported for names referenced in a preceding `global` statement. Refs [#10633](pylint-dev/pylint#10633) ## Other Bug Fixes - When displaying unicode with surrogates (or other potential `UnicodeEncodeError`), pylint will now display a '?' character (using `encode(encoding="utf-8", errors="replace")`) instead of crashing. The functional tests classes are also updated to handle this case. Closes [#8736](pylint-dev/pylint#8736) - Fixed unidiomatic-typecheck only checking left-hand side. Closes [#10217](pylint-dev/pylint#10217) - Fix a crash caused by malformed format strings when using `.format` with keyword arguments. Closes [#10282](pylint-dev/pylint#10282) - Fix false positive `inconsistent-return-statements` when using `quit()` or `exit()` functions. Closes [#10508](pylint-dev/pylint#10508) - Fix a crash in :ref:`nested-min-max` when using `builtins.min` or `builtins.max` instead of `min` or `max` directly. Closes [#10626](pylint-dev/pylint#10626) - Fixed a crash in :ref:`unnecessary-dict-index-lookup` when the index of an enumerated list was deleted inside a for loop. Closes [#10627](pylint-dev/pylint#10627) ## Other Changes - Remove support for launching pylint with Python 3.9. Code that supports Python 3.9 can still be linted with the `--py-version=3.9` setting. Refs [#10405](pylint-dev/pylint#10405) ## Internal Changes - Modified test framework to allow for different test output for different Python versions. Refs [#10382](pylint-dev/pylint#10382) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/repos/roboluke/pulls/384 Co-authored-by: renovate[bot] <[email protected]> Co-committed-by: renovate[bot] <[email protected]>

This PR contains the following updates: | Package | Change | Age | Confidence | |---|---|---|---| | [pylint](https://github.com/pylint-dev/pylint) ([changelog](https://pylint.readthedocs.io/en/latest/whatsnew/3/)) | `<4.0.0,>=3.3.3` -> `<4.1.0,>=4.0.0` | [![age](https://developer.mend.io/api/mc/badges/age/pypi/pylint/4.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/pylint/3.3.9/4.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | --- ### Release Notes <details> <summary>pylint-dev/pylint (pylint)</summary> ### [`v4.0.0`](https://github.com/pylint-dev/pylint/releases/tag/v4.0.0) [Compare Source](pylint-dev/pylint@v3.3.9...v4.0.0) - Pylint now supports Python 3.14. - Pylint's inference engine (`astroid`) is now much more precise, understanding implicit booleanness and ternary expressions. (Thanks [@zenlyj](https://github.com/zenlyj)!) Consider this example: ```python class Result: errors: dict | None = None result = Result() if result.errors: result.errors[field_key] ### inference engine understands result.errors cannot be None ### pylint no longer raises unsubscriptable-object ``` The required `astroid` version is now 4.0.0. See the [astroid changelog](https://pylint.readthedocs.io/projects/astroid/en/latest/changelog.html#what-s-new-in-astroid-4-0-0) for additional fixes, features, and performance improvements applicable to pylint. - Handling of `invalid-name` at the module level was patchy. Now, module-level constants that are reassigned are treated as variables and checked against `--variable-rgx` rather than `--const-rgx`. Module-level lists, sets, and objects can pass against either regex. Here, `LIMIT` is reassigned, so pylint only uses `--variable-rgx`: ```python LIMIT = 500 # [invalid-name] if sometimes: LIMIT = 1 # [invalid-name] ``` If this is undesired, refactor using *exclusive* assignment so that it is evident that this assignment happens only once: ```python if sometimes: LIMIT = 1 else: LIMIT = 500 # exclusive assignment: uses const regex, no warning ``` Lists, sets, and objects still pass against either `const-rgx` or `variable-rgx` even if reassigned, but are no longer completely skipped: ```python MY_LIST = [] my_list = [] My_List = [] # [invalid-name] ``` Remember to adjust the [regexes](https://pylint.readthedocs.io/en/latest/user_guide/messages/convention/invalid-name.html) and [allow lists](https://pylint.readthedocs.io/en/latest/user_guide/configuration/all-options.html#good-names) to your liking. ## Breaking Changes - `invalid-name` now distinguishes module-level constants that are assigned only once from those that are reassigned and now applies `--variable-rgx` to the latter. Values other than literals (lists, sets, objects) can pass against either the constant or variable regexes (e.g. "LOGGER" or "logger" but not "LoGgEr"). Remember that `--good-names` or `--good-names-rgxs` can be provided to explicitly allow good names. Closes [#3585](pylint-dev/pylint#3585) - The unused `pylintrc` argument to `PyLinter.__init__()` is deprecated and will be removed. Refs [#6052](pylint-dev/pylint#6052) - Commented out code blocks such as `# bar() # TODO: remove dead code` will no longer emit `fixme`. Refs [#9255](pylint-dev/pylint#9255) - `pyreverse` `Run` was changed to no longer call `sys.exit()` in its `__init__`. You should now call `Run(args).run()` which will return the exit code instead. Having a class that always raised a `SystemExit` exception was considered a bug. Normal usage of pyreverse through the CLI will not be affected by this change. Refs [#9689](pylint-dev/pylint#9689) - The `suggestion-mode` option was removed, as pylint now always emits user-friendly hints instead of false-positive error messages. You should remove it from your conf if it's defined. Refs [#9962](pylint-dev/pylint#9962) - The `async.py` checker module has been renamed to `async_checker.py` since `async` is a Python keyword and cannot be imported directly. This allows for better testing and extensibility of the async checker functionality. Refs [#10071](pylint-dev/pylint#10071) - The message-id of `continue-in-finally` was changed from `E0116` to `W0136`. The warning is now emitted for every Python version since it will raise a syntax warning in Python 3.14. See [PEP 765 - Disallow return/break/continue that exit a finally block](https://peps.python.org/pep-0765/). Refs [#10480](pylint-dev/pylint#10480) - Removed support for `nmp.NaN` alias for `numpy.NaN` being recognized in ':ref:`nan-comparison`'. Use `np` or `numpy` instead. Refs [#10583](pylint-dev/pylint#10583) - Version requirement for `isort` has been bumped to >=5.0.0. The internal compatibility for older `isort` versions exposed via `pylint.utils.IsortDriver` has been removed. Refs [#10637](pylint-dev/pylint#10637) ## New Features - `comparison-of-constants` now uses the unicode from the ast instead of reformatting from the node's values preventing some bad formatting due to `utf-8` limitation. The message now uses `"` instead of `'` to better work with what the python ast returns. Refs [#8736](pylint-dev/pylint#8736) - Enhanced pyreverse to properly distinguish between UML relationship types (association, aggregation, composition) based on object ownership semantics. Type annotations without assignment are now treated as associations, parameter assignments as aggregations, and object instantiation as compositions. Closes [#9045](pylint-dev/pylint#9045) Closes [#9267](pylint-dev/pylint#9267) - The `fixme` check can now search through docstrings as well as comments, by using `check-fixme-in-docstring = true` in the `[tool.pylint.miscellaneous]` section. Closes [#9255](pylint-dev/pylint#9255) - The `use-implicit-booleaness-not-x` checks now distinguish between comparisons used in boolean contexts and those that are not, enabling them to provide more accurate refactoring suggestions. Closes [#9353](pylint-dev/pylint#9353) - The verbose option now outputs the filenames of the files that have been checked. Previously, it only included the number of checked and skipped files. Closes [#9357](pylint-dev/pylint#9357) - colorized reporter now colorizes messages/categories that have been configured as `fail-on` in red inverse. This makes it easier to quickly find the errors that are causing pylint CI job failures. Closes [#9898](pylint-dev/pylint#9898) - Enhanced support for [@property](https://github.com/property) decorator in pyreverse to correctly display return types of annotated properties when generating class diagrams. Closes [#10057](pylint-dev/pylint#10057) - Add --max-depth option to pyreverse to control diagram complexity. A depth of 0 shows only top-level packages, 1 shows one level of subpackages, etc. This helps manage visualization of large codebases by limiting the depth of displayed packages and classes. Refs [#10077](pylint-dev/pylint#10077) - Handle deferred evaluation of annotations in Python 3.14. Closes [#10149](pylint-dev/pylint#10149) - Enhanced pyreverse to properly detect aggregations for comprehensions (list, dict, set, generator). Closes [#10236](pylint-dev/pylint#10236) - `pyreverse`: add support for colorized output when using output format `mmd` (MermaidJS) and `html`. Closes [#10242](pylint-dev/pylint#10242) - pypy 3.11 is now officially supported. Refs [#10287](pylint-dev/pylint#10287) - Add support for Python 3.14. Refs [#10467](pylint-dev/pylint#10467) - Add naming styles for `ParamSpec` and `TypeVarTuple` that align with the `TypeVar` style. Refs [#10541](pylint-dev/pylint#10541) ## New Checks - Add `match-statements` checker and the following message: `bare-name-capture-pattern`. This will emit an error message when a name capture pattern is used in a match statement which would make the remaining patterns unreachable. This code is a SyntaxError at runtime. Closes [#7128](pylint-dev/pylint#7128) - Add new check `async-context-manager-with-regular-with` to detect async context managers used with regular `with` statements instead of `async with`. Refs [#10408](pylint-dev/pylint#10408) - Add `break-in-finally` warning. Using `break` inside the `finally` clause will raise a syntax warning in Python 3.14. See `PEP 765 - Disallow return/break/continue that exit a finally block <https://peps.python.org/pep-0765/>`\_. Refs [#10480](pylint-dev/pylint#10480) - Add new checks for invalid uses of class patterns in :keyword:`match`. - :ref:`invalid-match-args-definition` is emitted if :py:data:`object.__match_args__` isn't a tuple of strings. - :ref:`too-many-positional-sub-patterns` if there are more positional sub-patterns than specified in :py:data:`object.__match_args__`. - :ref:`multiple-class-sub-patterns` if there are multiple sub-patterns for the same attribute. Refs [#10559](pylint-dev/pylint#10559) - Add additional checks for suboptimal uses of class patterns in :keyword:`match`. - :ref:`match-class-bind-self` is emitted if a name is bound to `self` instead of using an `as` pattern. - :ref:`match-class-positional-attributes` is emitted if a class pattern has positional attributes when keywords could be used. Refs [#10587](pylint-dev/pylint#10587) - Add a `consider-math-not-float` message. `float("nan")` and `float("inf")` are slower than their counterpart `math.inf` and `math.nan` by a factor of 4 (notwithstanding the initial import of math) and they are also not well typed when using mypy. This check also catches typos in float calls as a side effect. The :ref:`pylint.extensions.code_style` need to be activated for this check to work. Refs [#10621](pylint-dev/pylint#10621) ## False Positives Fixed - Fix a false positive for `used-before-assignment` when a variable defined under an `if` and via a named expression (walrus operator) is used later when guarded under the same `if` test. Closes [#10061](pylint-dev/pylint#10061) - Fix :ref:`no-name-in-module` for members of `concurrent.futures` with Python 3.14. Closes [#10632](pylint-dev/pylint#10632) ## False Negatives Fixed - Fix false negative for `used-before-assignment` when a `TYPE_CHECKING` import is used as a type annotation prior to erroneous usage. Refs [#8893](pylint-dev/pylint#8893) - Match cases are now counted as edges in the McCabe graph and will increase the complexity accordingly. Refs [#9667](pylint-dev/pylint#9667) - Check module-level constants with type annotations for `invalid-name`. Remember to adjust `const-naming-style` or `const-rgx` to your liking. Closes [#9770](pylint-dev/pylint#9770) - Fix false negative where function-redefined (E0102) was not reported for functions with a leading underscore. Closes [#9894](pylint-dev/pylint#9894) - We now raise a `logging-too-few-args` for format string with no interpolation arguments at all (i.e. for something like `logging.debug("Awaiting process %s")` or `logging.debug("Awaiting process {pid}")`). Previously we did not raise for such case. Closes [#9999](pylint-dev/pylint#9999) - Fix false negative for `used-before-assignment` when a function is defined inside a `TYPE_CHECKING` guard block and used later. Closes [#10028](pylint-dev/pylint#10028) - Fix a false negative for `possibly-used-before-assignment` when a variable is conditionally defined and later assigned to a type-annotated variable. Closes [#10421](pylint-dev/pylint#10421) - Fix false negative for `deprecated-module` when a `__import__` method is used instead of `import` sentence. Refs [#10453](pylint-dev/pylint#10453) - Count match cases for `too-many-branches` check. Refs [#10542](pylint-dev/pylint#10542) - Fix false-negative where :ref:`unused-import` was not reported for names referenced in a preceding `global` statement. Refs [#10633](pylint-dev/pylint#10633) ## Other Bug Fixes - When displaying unicode with surrogates (or other potential `UnicodeEncodeError`), pylint will now display a '?' character (using `encode(encoding="utf-8", errors="replace")`) instead of crashing. The functional tests classes are also updated to handle this case. Closes [#8736](pylint-dev/pylint#8736) - Fixed unidiomatic-typecheck only checking left-hand side. Closes [#10217](pylint-dev/pylint#10217) - Fix a crash caused by malformed format strings when using `.format` with keyword arguments. Closes [#10282](pylint-dev/pylint#10282) - Fix false positive `inconsistent-return-statements` when using `quit()` or `exit()` functions. Closes [#10508](pylint-dev/pylint#10508) - Fix a crash in :ref:`nested-min-max` when using `builtins.min` or `builtins.max` instead of `min` or `max` directly. Closes [#10626](pylint-dev/pylint#10626) - Fixed a crash in :ref:`unnecessary-dict-index-lookup` when the index of an enumerated list was deleted inside a for loop. Closes [#10627](pylint-dev/pylint#10627) ## Other Changes - Remove support for launching pylint with Python 3.9. Code that supports Python 3.9 can still be linted with the `--py-version=3.9` setting. Refs [#10405](pylint-dev/pylint#10405) ## Internal Changes - Modified test framework to allow for different test output for different Python versions. Refs [#10382](pylint-dev/pylint#10382) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/repos/epage/pulls/168 Co-authored-by: renovate[bot] <[email protected]> Co-committed-by: renovate[bot] <[email protected]>

cdce8p added this to the 4.0.0 milestone Sep 24, 2025

cdce8p added Enhancement ✨ Improvement to a component Match case labels Sep 24, 2025

Add additional checks for match class patterns

42b289d

cdce8p force-pushed the additional-match-checks branch from f6d8d9d to 42b289d Compare September 24, 2025 20:29

Fix functional tests

279e8cc