Changelog

Changes

All of these changes are highlights, there’s always smaller bugfixes included.

0.9.0 (2026-06-23)

  • Breaking: The mode selection had bugs in some cases. Now the mode selection is what was promised in 0.7.0: “default” by default when running zuban check and “mypy” when running zuban mypy. The language server uses the new mode “auto” that tries to detect Mypy settings. 0.7.0 tried to do this already but had some bugs. These are now fixed. There’s an explanation at modes.

  • Many bugfixes for typechecking

  • Added --extra-search-paths

  • Added Mypy’s --custom-typeshed-dir

  • Added --mode auto and mode = "auto" in the zuban config

0.8.2 (2026-06-09)

  • Added better support for pip install -t

0.8.1 (2026-06-08)

  • Adding support for some initializationOptions that are used in the new VSCode plugin:

    • typeCheckingMode can be auto (default), off, default or mypy. This is especially useful to disable type checking.

    • disableLanguageServices a boolean to disable all language services except type checking.

    • diagnosticMode can be open-files-only (default) or workspace. This makes Zuban report more errors in the workspace case.

    • pythonExecutable a string (path) to the python executable of an environment. The exact same option is available when executing zuban check --python-executable <path>.

  • Adding a custom status API that is used in the new VSCode plugin.

  • Added an sdist release (to PyPI)

0.8.0 (2026-06-01)

This release is only relevant for LSP (language server protocol) related changes. The type checker was not changed.

  • Zuban now uses heuristics for completions, goto, hover and signatures. This improves completions by a lot for untyped code. For example Zuban is now able to complete both of these:

    def foo(x):
  x.  # Zuban type checking thinks this
      # is Any, but completes `list`,
      # because it searches call sites.
  return x[0]

foo(['']).  # Zuban type checking thinks that this
            # is Any, but completes `str`, because
            # it follows the function call.

  • The sys path for LSP does now match what zuban check would find. Previously Zuban did just believe the LSP roots. However LSP clients are often wrong. The LSP roots are now only used as a hint.

  • Introduced many small improvements that are part of Jedi’s tests. Now Zuban passes about 92% of Jedi’s tests, where previously it would pass only 80%.

  • Zuban LSP works now in functions that Zuban/Mypy would typically not check because of the (default) flag --no-check-untyped-defs.

  • Zuban completions and goto now work on third-party modules that have no py.typed module inside them and are considered to be Any by the type checker.

0.7.2 (2026-05-03)

  • Implement sentinels

  • Fixes an annoying regression around abstractmethods

0.7.1 (2026-04-25)

  • Basic support for template strings (Python 3.14 t"..." syntax)

  • Upgrade typeshed

  • Completions in comments (LSP)

  • Implement disjoint_base (PEP 800)

  • Implement conditional fields for NamedTuple and TypedDict

  • Implement shell expansion for mypy_path in config

  • Fix finding typeshed for Debian based systems if installed as root

0.7.0 (2026-04-06)

  • Breaking: The default mode is now “default” even if there is Mypy specific config (e.g. mypy.ini). Previously the “mypy” mode would be chosen in such cases. Mypy config is still read, though. This does not matter if you run zmypy or zuban mypy. However if you want to use the language server you may want to add a mode = "mypy" to the [tool.zuban] section in pyproject.toml. The reason for this change is that the previous logic was too complicated for users to understand. Now it’s pretty simple: The mode is always “default” except if it’s explicitly chosen otherwise.

  • Django *_id attributes and completions now work

  • Error codes for overrides do now match Mypy’s error codes closer

  • Better hover for type aliases, type variables (LSP)

  • References are now sorted in a more useful way (LSP)

  • Removed the undocumented zubanls executable which was documented only in very early releases (before 0.0.20)

  • Improved support for typing_extensions usages

  • Improved speed a lot for some TypedDict matching

  • Fixed a lot of crashes

0.6.2 (2026-03-16)

  • Union matching for large literal unions (> 100 items) is now not exponential anymore and therefor exponentially faster :-)

  • sys.path improvements (mostly for uv users):

    • The src/ subfolder in a project is now added to the path

    • Nested folders with their own local imports are now also possible. The parent folder of the most outer __init__.py is assumed to be the package name

    • Added --explicit-package-bases, which Mypy also uses to disable these heuristics

    • $VIRTUAL_ENV now has lower priority than searching local folders for virtual envs. The problem is that this variable is quite unreliable in some cases, especially when zuban is run from a virtualenv itself

  • Better keyword argument completions (LSP)

  • Zuban is in general about 30% faster for large projects:

    • Imports are now a lot faster in large projects

    • The parser is now faster by a few percent

  • The parser had stalls due to exponential reparsing, which is now fixed

0.6.1 (2026-02-25)

  • Using zmypy is now possible from a subdir. It respects relative paths and will typecheck the whole project if no explicit paths are given

  • Fixed a problematic bug when working with nested workspaces. This was often problematic when using uv

  • Added a few more cases where inlay hints are useful when generics are present (LSP)

0.6.0 (2026-02-19)

  • Add pytest fixture inference, completions and goto

  • Added the code action to add # type: ignore[<error-code>] at the end of the line when errors are present

  • Code actions are now more gracious and give you actions for the full line even if the cursor is not directly on it

0.5.1 (2026-02-09)

  • Implemented Mypy’s ignore_errors = true correctly. This makes it possible to avoid showing diagnostics in a LSP process.

  • Fixed the sys path when site-packages are used in a default environment

0.5.0 (2026-02-07)

  • By default enable –untyped-strict-optional in the default mode. This reduces a lot of false positives in untyped code.

  • Fixed many issues around untyped code

    • Muted errors for example around incomplete list generics, which are common in untyped code.

    • Does not infer generics for params anymore by default, this is too noisy for now.

  • try: ... except AttributeError now mutes errors in the case where an attribute exists on some parts of the union, but not on others.

  • In addition to specifying type: ignore you can now use zuban: ignore

  • Changed --mypy-compatible to --mode mypy and --no-mypy-compatible to --mode default

  • It is now possible to specify mode = "mypy" or mode = "default" in pyproject.toml

0.4.2 (2026-01-16)

  • Bugfixes

0.4.1 (2025-12-27)

  • Bugfixes

0.4.0 (2025-12-20)

  • Get a lot closer to passing conformance tests

0.3.0 (2025-12-02)

  • Add inlay hints (LSP)

  • Django model support, implements type checking and completions (LSP)

  • Added autocompletion resolve, which means documentation for completion items is now available (LSP)

  • Added support for Conda (that CONDA_PREFIX is now recognized)

  • Many fixes for crashes

0.2.3 (2025-11-17)

  • Added autoimport actions (LSP)

  • Better documentation Markdown formatting (LSP)

0.2.2 (2025-11-03)

  • Bug fixes

0.2.1 (2025-10-30)

  • Implemented semantic colors and selection ranges (LSP)

  • Fixed a problem that caused Zuban to not terminate

0.2.0 (2025-10-23)

  • Added Notebook support in LSP (completions, goto, rename, etc.)

0.1.2 (2025-10-22)

  • Added musllinux builds to the PyPI release:

    • armv7-unknown-linux-musleabihf

    • aarch64-unknown-linux-musl

    • x86_64-unknown-linux-musl

    • i686-unknown-linux-musl

0.1.1 (2025-10-15)

  • Added call signatures to LSP

0.1.0 (2025-10-10)

  • This is the Zuban Beta release, because it feels very stable now

  • Fix more crashes

0.0.25 (2025-10-07)

  • Full support for pattern matching (match and case narrowing)

  • The PYTHONPATH and MYPYPATH environment variables are now used for the sys.path

  • Fixes for many crashes and bugs

0.0.24 (2025-09-23)

  • Full support for TypedDict extra_items/closed (PEP 728)

  • Support for reporting deprecated usages of classes/functions, by using --enable-error-code deprecated

  • Support for LiteralString and Literal operations, "a" + "b" would result in the type Literal["ab"].

  • Support for the TypeVar(..., infer_variance=True) argument

  • Now all conformance tests are at least partially supported

0.0.23 (2025-09-12)

  • Better virtualenv support: In case where no $VIRTUAL_ENV is found

  • .pth file support, this enables for example uv workspaces

  • Added colors to the command line

  • Support for --pretty and the pretty = true to have more infos about the error location when running on the command line

  • Added support for typing.LiteralString and literal operations (e.g. "a" + "b" would result in the literal "ab"

  • Added support for __call__ in metaclasses

0.0.22 (2025-09-04)

  • pyproject.toml now supports [tool.zuban] for configuration

  • Various bug fixes

0.0.21 (2025-09-03)

  • Open Sourced with an AGPL license

0.0.20 (2025-08-28)

  • Performance optimizations (some multi-threading, generally about 20% faster)

  • zuban is now the main executable, zubanls and zmypy simply call zuban. To type check code, use zuban check or zuban mypy (to ensure Mypy-like behavior). To start the language server, you can simply use zuban server.

  • Fixing a lot of crashes

0.0.19 (2025-08-11)

  • Fix a lot of details around diagnostics to satisfy most conformance tests

0.0.18 (2025-07-31)

  • Add language server (LSP) capabilities for

    • Completions

    • Goto (definitions, declarations, implementations, type-definitions)

    • Hover

    • References / Document Highlights

    • Rename

  • Add type inference for untyped returns, when running zuban check. def foo(x): return [x] would be inferred as Callable[[T], list[T]]

0.0.1 - 0.0.17

  • Initial releases of zuban with basic type checking