Pyrefly v0.26.0

Status: ALPHA

Release date: 2025-07-28

Pyrefly 0.26.0 bundles 179 commits from 24 contributors

📝 Changelog

Configuration

• Added a "disable-search-path-heuristics" to disable search path heuristics for users that want to configure all imports manually.
• Fixed issues with the --watch flag.
• Support .pyx, .pyd, and .pyw compiled files for module finding and globbing.
• Disabled imports from pycache to prevent incorrect imports.

Typechecking Features

• Fix several bugs with variable scopes.
• Warn on calling deprecated overloads.
• Added support for checking code snippets directly from the command line.
• Disallowed attribute assignment or deletion on super() objects.
• Emit an error when an uncalled function is used as the condition for an if statement.
• Improved new and init_subclass behavior.
• Enabled support for descriptors in dataclass fields.
• Fixed bugs related to TypedDict operations, including setitem and matching against PartialTypedDict.
• Fix bug with synthesized namedtuple constructors.

IDE

• Optimized autocomplete by filtering local variable results and providing a specialized path for builtins, effectively improving auto-import behavior.

Other

• Enhanced performance with caching for node packages and rust-cache.
• Improved display of default values and type information.
• Improved subscript error messages to indicate non-subscriptable types.
• Summary display is now more concise by default, with options for detailed or no summary.

📦 Upgrade

pip install --upgrade pyrefly==0.26.0

🖊️ Contributors this release

@grievejia @samwgoldman @stroxler @rchen152 @fangyi-zhou @ndmitchell @rubmary @kinto0 @arthaud @lolpack @migeed-z @darricklaidin @connernilsen @regexyl @danielocfb @WeixiMa @MaggieMoss @yangdanny97

Full Changelog: https://github.com/facebook/pyrefly/compare/0.25.0..0.26.0

Pyrefly v0.25.0

Status: ALPHA

Release date: 2025-07-22

Pyrefly 0.25.0 bundles 307 commits from 19 contributors

📝 Changelog

• Error Handling Improvements:
  • Avoid redundant error messages for positional arguments.
  • Show environment query errors and config loading errors in IDE.
• Class and Attribute Handling:
  • Changed semantics of class objects initialized on class bodies.
  • Improved handling of read-only class attributes.
• IDE Enhancements:
  • Support for "jump to definition" on hover.
  • Optimized module path sorting.
• Type System Enhancements:
  • Improve handling for typing.Self.
• Configuration and Migration:
  • Added support for ignore_missing_imports in Pyrefly config.
  • Improved config migration logic and added tests for various config options.
• Error and Warning Enhancements:
  • Warn on deprecated method calls and overloaded calls.
  • Improve error labeling and severity-based color coding.
• TypedDict Improvements:
  • Check keyword arguments in TypedDict initialization & makeself positional-only.
• Documentation and Usability:
  • Updated documentation for IDE settings and config options.
• Miscellaneous:
  • Raise error on variable use-before-assignment.
  • Improved mutable capture for global and nonlocal variables.

📦 Upgrade

pip install --upgrade pyrefly==0.25.0

🖊️ Contributors this release

@rchen152 @stroxler @ndmitchell @yangdanny97 @arthaud @kinto0 @connernilsen @SamChou19815 @rubmary @dluo @migeed-z @samwgoldman @fangyi-zhou @LyricalToxic @melvinhe @grievejia @lolpack

Full Changelog: 0.24.2...0.25.0

Pyrefly v0.24.2

Status: ALPHA

Release date: 2025-07-15

Pyrefly 0.24.2 bundles 290 commits from 26 contributors

📝 Changelog

• Type System Enhancements: Improved handling of type() and bool() for narrowing, and the behavior for match statements w/ class patterns
• Dataclass Transform: Full support for dataclass_transform
• Interpreter Query Optimization: Significant reduction in import times and memory usage by optimizing search path handling and deduplication of search path entries.
• Error Handling and Reporting: Introduced CLI flags to configure error severity for individual error codes (--error, --warn, --ignore) and improved error message clarity.
• Semantic Tokens: Fixed issues with semantic tokens on the first line and improved deduplication logic.
• Binop Support: Fixed issues with operations like float * bool and complex * bool.
• Workspace Symbols: Implemented workspace symbol support using the fuzzy search infrastructure for auto-import.
• Configuration Improvements: Added --typeshed-path CLI flag for custom typeshed modifications and improved config handling logic.

📦 Upgrade

pip install --upgrade pyrefly==0.24.2

🖊️ Contributors this release

@ndmitchell, @yangdanny97, @stroxler, @rchen152, @migeed-z, @connernilsen, @dluo, @MaggieMoss, @rubmary, @xaskii, @kinto0, @grievejia, @SamChou19815, @melvinhe, @lianne, @krikera, @dluo, @Abel981, @fangyi-zhou, @Alex-Aron, @zpao, @slawlor, @diliop, @arnav-jain1, @samwgoldman

v0.23.0

Pyrefly 0.23.0

Status: ALPHA
Release date: 2025-07-07

Pyrefly 0.23.0 bundles 186 commits from 24 contributors. This release introduces significant improvements in type checking, configuration handling, and error management.

---

📝 Changelog

• Dataclass improvements: Added checks for dataclas field ordering, keyword arguments, and inheritance, aligning with Python's typing specification. Started implementing support for dataclass transforms.
• Error Handling and Suppression: Introduced more robust error handling and suppression options. Error suppression comments can now specify the type of error being suppressed, and are less sensitive to whitespace.
• Go-to-def Enhancements: Added support for resolving a single goto-def request to multiple definitions.
• Configuration and Environment Updates: Better error reporting and support for conda environments.
• Jupyter Notebook Integration: Pyrefly can now work on notebooks in Jupyter Lab, via the jupyterlab-lsp extension.

---

📦 Upgrade

pip install --upgrade pyrefly==0.23.0

🖊️ Contributors this release

@aahanaggarwal, @yangdanny97, @stroxler, @rchen152, @dluo, @ndmitchell, @connernilsen, @xaskii, @melvinhe, @migeed-z, @TheRustyPickle, @arnav-jain1, @InSyncWithFoo, @rubmary, @arthaud, @samwgoldman, @grievejia, @danielocfb-test, @MaggieMoss, @DavidTolnay, @junhao, @darricklaidin, @kinto0

v0.22.0

Pyrefly 0.22.0

Status : ALPHA

Release date: 30 Jun 2025

Pyrefly 0.22.0 bundles 216 commits from 23 contributors. This release includes significant improvements in type checking and performance enhancements.

---

✨ New & Improved

Area	What’s new
Type Checking	Implemented support for functools.total_ordering, allowing automatic generation of rich comparison methods.
IDE / LSP	Added support for textDocument/rename and textDocument/prepareRename in LSP.
Configuration	Introduced CLI flag for --conda-environment to manage Python environments more effectively.

---

🐛 Other bug fixes

• Fixed bugs in attribute narrowing and method overrides.
• Resolved issues with NamedTuple field ordering and TypedDict method synthesis.
• Values with type[tuple] can now be used as a tuple constructor
• Enums can now be subscripted with any str, not just literals.

---

📦 Upgrade

pip install --upgrade pyrefly==0.22.0

🖊️ Contributors this release

@Adist319, @adsi7698, @bigfootjon, @connernilsen, @CookieComputing, @dluo, @facebook-github-bot, @fangyi-zhou, @grievejia, @iwakitakuma33, @kinto0, @krathul, @melvinhe, @migeed-z, @ndmitchell, @pt2302, @rchen152, @SamChou19815, @stroxler, @vagabond-0, @xaskii, @yangdanny97, @zsol

Previous Release Notes

https://github.com/facebook/pyrefly/releases

Full Changelog: 0.21.0...0.22.0

v0.21.0

Pyrefly 0.21.0

Status : ALPHA
Release date: 23 June 2025

Pyrefly 0.21.0 delivers 176 commits from 20 contributors. We now support a number of highly requested features such as Semantic Highlighting, Signature Help, Document Highlights and Auto Import Completions! Follow along for more LSP functionality #344 ahead of our V1 release.

---

✨ New & Improved

Area	What’s new
IDE / LSP (Issue #344)	• Richer semantic highlighting – method calls, property accesses, and the expressions nested in them now get distinct token types, so editors like VS Code underline exactly what you expect (#344). • Added the defaultLibrary semantic-token modifier for symbols originating from builtins, typing, or typing_extensions; makes built-ins stand out in both dark/light themes.
Diagnostics	• Detailed override errors – incompatibilities between a subclass attribute and its parent now explain why they don’t match (“read-write vs read-only”, “int vs str”, etc.) on a second indented line.
Type-system smarts	• InitVar fields in @dataclass definitions are no longer treated as instance attributes, eliminating false “missing attribute” errors (PR [#437]). • Full support for Variance Inference in Generic Classes with PEP 695
Performance	• A pathological Callable | … union test that once blew up exponentially now checks in linear time.

---

🐛 Other bug fixes

• Multiple edge-case panics removed, including starred targets inside augmented assignments and cyclic class-type substitutions.
• Hover & go-to-definition in LSP no longer crash when traversing keyword-only or pattern-match bindings.
• Cargo / Rust nightly warnings cleaned up; WASM build green again.

---

🚨 Potentially breaking

• The new, more explicit override-mismatch diagnostics may fail code that relied on silent attribute-type changes.
• Editors that hard-code semantic-token kinds should be updated to recognise the new defaultLibrary modifier.

---

📦 Upgrade

pip install --upgrade pyrefly==0.21.0

🖊️ Contributors this release

@yangdanny97 @Adist319 @grievejia @connernilsen @migeed-z @ndmitchell @xl4624 @stroxler @rchen152 @TheRustyPickle @dluo @kinto0 @pt2302 @SamChou19815 @ducdetronquito @xaskii @Alex-Aron @hugovk @grantlouisherman @rubmary

v0.20.0

Pyrefly 0.20.0

Status : ALPHA
Release date: 16 June 2025

Pyrefly 0.20.0 represents 165 commits from 21 contributors and focuses on stability, friendlier diagnostics, and CLI quality-of-life.

Special thanks to @TheRustyPickle, @ducdetronquito, @pt2302, @akmalsoliev and every reviewer, tester and bug-reporter who helped make this release!

---

✨ New & Improved

Area	What’s new
Diagnostics & error messages	•We now print a snippet of source code in each message, highlighting the error location. You can control error message verbosity with the new --output-format=min-text and --output-format=full-text options. •Add tests to keep Error Kinds in sync with documentation, in addition to reclassifying Error Kinds previously reported as Unknown (#477). • Import errors are now shown on separate lines with source hints, thanks to the new BindingsBuilder::error_multiline helper (commit 2bba00f). •TypeVar reveal output is shorter and clearer – no more variance=PInvariant noise (#225).
Editor support	•Basic support for Semantic Highlighting, a highly requested feature (#218). More improvements to come in future releases.
Configuration / CLI	• New flags --replace-imports-with-any and --ignore-missing-source let you suppress noisy import errors without editing config files (#480 → closes #460 & #462).
Type-system smarts	• Conflicting Required/NotRequired qualifiers in a single TypedDict field now surface an explicit error (#447→ fixes #414).
Project workflow	• pyrefly init edits an existing pyproject.toml in-place instead of appending duplicate [tool.pyrefly] sections (#336).

---

🐛 Other notable bug fixes

• Panics fixed:
  • Missing NoneType stub when running with --python-version 3.9 (#56).
  • Starred targets in augmented assignments no longer crash the checker (#468).
• Hover & go-to-definition no longer crash the LSP on keyword-only or pattern-match bindings.
• Build is quiet again on nightly Rust; cleaned up stray clippy warnings.

---

🚨 Potentially breaking

• Flag & message renames – some diagnostics switched from snake-case to kebab-case and new CLI flags were introduced (#480). Update any scripts that parse pyrefly check --help or grep error kinds.
• The TypedDict qualifier rule (#447) may surface new errors where both Required and NotRequired were previously accepted.

---

📦 Upgrade

pip install --upgrade pyrefly==0.20.0

---

🖊️ Contributors in this release

@rchen152, @grievejia, @stroxler, @ajaymiranda, @connernilsen, @pt2302, @kinto0, @yangdanny97, @ndmitchell, @migeed-z, @hugovk, @dtolnay, @Alex-Aron, @Adist319, @zachmullen, @grantlouisherman, @rubmary, @dluo, @MaggieMoss, @kinto0, @SamChou19815

v0.19.0

Pyrefly 0.19.0

Status : ALPHA

Release date: 9 June 2025

Pyrefly 0.19.0 packs a week’s worth of fixes and quality‑of‑life improvements into 128 commits from 19 contributors, touching 153 files.

Thank you @ajaymiranda @Adist319 @Alex-Aron @zachmullen for your contributions!

---

✨ New & Improved

Area	What’s new
Editor support	• Neovim integration — first‑class LSP support plus a helper command to install/update the server (#227). • Neovim now respects pyrefly.toml and remote config overrides (#442).
Configuration UX	• Eliminates misleading “Extra keys” parse errors in pyrefly.toml (#441). • Added validation that a TypedDict field cannot be both Required and NotRequired (#414).
Diagnostics	• reveal_type messages are now INFO‑level instead of errors, so they no longer fail CI runs when you’re just inspecting types (#304). • isinstance() checks involving Union[...] are now inferred correctly (#426).
Type‑system smarts	• Better handling of Self generics in chained method calls (#152). • Fixed constrained TypeVar attribute access (#318). • Fixed failure when calling methods on a plain TypeVar (#150).
Stub & third‑party typing	• Works with inline stub files that live beside their implementation (#419). • Correctly recognises pandas-stubs generic aliases such as Index without type arguments (#427).

---

🐛 Other notable bug fixes

• Duplicate “NoReturn / Never” return‑annotation error reduced to a single authoritative report (#425).
• Numerous minor LSP crashes and hover glitches fixed.
• Documentation on website and CLI cleanup

---

🚨 Potentially breaking

• The new TypedDict qualifier rule (#414) will surface errors in code that previously passed silently.
• If you relied on reveal_type raising an error exit status, update scripts to look for an info‑level diagnostic instead (#304).

---

📦 Upgrade

pip install --upgrade pyrefly==0.19.0

🖊️ Contributors in this release

@Adist319, @Alex-Aron, @connernilsen, @yangdanny97, @dluo , @dtolnay, @hugovk, @grantlouisherman, @grievejia, @kinto0, @MaggieMoss, @ndmitchell, @rchen152, @rubmary, @SamChou19815, @stroxler, @migeed-z