v9.1.1

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pytest 9.1.1 (2026-06-19)

Bug fixes

• #​14220: Fixed a logic bug in pytest.RaisesGroup which would might cause it to display incorrect "It matches FooError() which was paired with BarError" messages.
• #​14591: Fixed a regression in pytest 9.1.0 which caused overriding a parametrized fixture with an indirect @​pytest.mark.parametrize to fail with "duplicate parametrization of '<fixture name>'".
• #​14606: Fixed list-item typing errors from mypy in @pytest.mark.parametrize <pytest.mark.parametrize ref> argvalues parameter.
• #​14608: Fixed a regression in pytest 9.1.0 where conftest.py files located in <invocation dir>/test* were no longer loaded as initial conftests when invoked without arguments.
  This could cause certain hooks (like pytest_addoption) in these files to not fire.

v0.15.18

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Released on 2026-06-18.

Preview features

• Handle nested ruff:ignore comments (#​25791)
• Stop displaying severity in output (#​26050)
• Use human-readable names in CLI output (#​25937)
• Use human-readable names in LSP and playground diagnostics (#​26058)
• [pydocstyle] Prevent property docstrings starting with verbs (D421) (#​23775)
• [flake8-pyi] Extend PYI033 to Python files (#​26129)

Bug fixes

• Detect equivalent numeric mapping keys (#​26009)
• Detect mapping keys equivalent to booleans (#​25982)
• Detect repeated signed and complex dictionary keys (#​26007)

Rule changes

• [flake8-pyi] Rename PYI033 to legacy-type-comment (#​26131)

Performance

• Use ThinVec for call keywords (#​25999)
• Inline parser recovery context checks (#​26038)
• Match parser keywords as bytes (#​26037)
• Move value parsing out of lexing (#​25360)

Server

• Render subdiagnostics and secondary annotations as related information (#​26011)

Documentation

• Update fix availability for always-fixable rules (#​26091)
• [flake8-tidy-imports] Add fix safety section (TID252) (#​17491)

Parser

• Reject __debug__ lambda parameters (#​26022)
• Reject _ as a match-pattern target (#​25977)
• Reject multiple starred names in sequence patterns (#​25976)
• Reject parenthesized star imports (#​26021)
• Reject starred comprehension targets (#​26023)
• Reject unparenthesized generator expressions in class bases (#​25978)
• Reject yield expressions after commas (#​26024)
• Validate function type parameter default order (#​25981)

Playground

• Make diagnostic links clickable (#​26104)
• Use diagnostic tags (#​26105)

Contributors

• @​AlexWaygood
• @​ntBre
• @​gtkacz
• @​MichaReiser
• @​charliermarsh
• @​Kalmaegi

v0.0.51

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Released on 2026-06-18.

Bug fixes

• Fix bound TypeVar default cycle recovery (#​26124)
• Support Annotated[Any, ...] as a class base (#​26133)

LSP server

• Suggest keyword-only arguments between variadic parameters (#​26134)

Core type checking

• Avoid assuming classes with Any or Unknown bases are descriptors (#​26120)
• Infer simpler types in complex lambda cycles (#​26137)
• Preserve exact class objects during identity narrowing (#​26117)

Diagnostics

• Preserve unpacking diagnostics for nested assignment targets (#​26121)

Performance

• Compact indexed AST node storage (#​25998)
• Discard dead DNF branches in intersection building (#​26144)

Documentation

• Remove broken gradual guarantee link (#​3806)

Contributors

• @​charliermarsh
• @​ibraheemdev
• @​carljm
• @​MichaReiser
• @​sharkdp

v0.0.50

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Released on 2026-06-17.

Bug fixes

• Avoid cross-TypeVar leakage in generic inference (#​26099)
• Fix panic from oscillating collection-use constraints (#​26031)
• Preserve type variables in fixed tuple aliases (#​26041)
• Respect ParamSpec binding contexts (#​25993)
• Show bare Final as a special form on hover (#​26029)
• Support options in functional dataclass calls (#​25989)

LSP server

• Add context-sensitive keyword completions (#​26036)
• Fix wildcard import symbol range (#​25740)
• Highlight decorated methods consistently (#​26003)
• Preserve narrowing after qualified TYPE_CHECKING (#​26051)
• Respect client's content format preference (#​25957)
• Retain all diagnostic annotations in the server (#​26006)
• Track unused-binding captures across nested scopes (#​25536)

Diagnostics

• Fix override diagnostics for decorated methods (#​25671)
• Improve duplicate-base diagnostics (#​26107)
• Reject invalid dataclass flag combinations (#​25985)
• Reject legacy TypeVars in PEP 695 class bases (#​25975)
• Reject legacy TypeVars in PEP 695 functions (#​25979)
• Respect @no_type_check in function validation (#​25994)

Performance

• Avoid rebuilding unchanged specializations (#​25826)
• Avoid redundant equality intersections (#​26057)
• Avoid retaining empty use-def tables (#​26018)
• Compact retained definition inference extras (#​25838)
• Deduplicate retained scope inference types (#​25846)
• Disable LRU tracking for one-shot checks (#​26106)
• Fast path collection literals with exact type contexts (#​25878)
• Flatten retained declaration states (#​25912)
• Improve flow snapshot performance (#​26012)
• Skip stub package checks in stub-free search paths (#​25963)
• Speed up large-union narrowing (#​26048)
• Speed up module resolution for projects with many search paths (#​25962)
• Store cumulative binding end offsets (#​25913)
• Use compact frozen representation for narrowing constraints (#​25990)

Core type checking

• Annotate intersection and negation types using & and ~ (#​26035)
• Diagnose zero-step slices on lists (#​25966)
• Full-scope bidirectional inference for non-empty collection literals (#​25280)
• Improve equality-based narrowing for ==, !=, and match (#​25788)
• Infer precise values for standard-library enums (#​26103)
• Make equality evaluation cycle-aware (#​26055)
• Narrow equality across IntEnum classes (#​26079)
• Narrow tuple expression match subjects (#​25874)
• Preserve literal types for loop variables over literal collections (#​25083)
• Preserve negative narrowing for starred sequence patterns (#​25927)
• Preserve non-final types in Hashable unions (#​26039)
• Support enum literals as tagged-union discriminants (#​25855)
• Sync vendored typeshed stubs (#​25952). Typeshed diff
• Sync vendored typeshed stubs (#​25997). Typeshed diff
• Synthesize NamedTuple __match_args__ (#​25934)
• Treat assigned enum hooks conservatively (#​25958)
• Validate deprecated warning categories (#​26025)

Contributors

• @​AlexWaygood
• @​MichaReiser
• @​ankddev
• @​sqqueak
• @​lerebear
• @​sharkdp
• @​denyszhak
• @​ibraheemdev
• @​charliermarsh