Pytype is a fairly popular static type analyzer that was developed internally at Google to meet the company"s needs for testing Python code. It isn"t an official Google product but was widely used within the company to infer types even when explicit annotations are absent, without running the code. It is also available as a GitHub repository for members of the public to leverage, but it has now been discontinued.
In an update to the GitHub repository"s README file, the developers have announced that Python 3.12 will be the last supported version of the programming language. They have noted that while the tool was developed back in 2012 to meet the demands of Google developers for compile-time type checking, its bytecode-based architecture meant that there were numerous complexities associated with implementing features that accommodate new Python Enhancement Proposals (PEPs). This has been blamed on bytecode"s "inherent instability and propensity to change".
This is why the developers are shifting focus to other areas and frameworks, despite still being actively interested in the Python type checking space. It has also asked affected developers to search for other mature solutions to meet their type checking needs, especially considering that the ecosystem is much more robust now.
Pytype was primarily developed and supported for use on Linux, but it also worked on macOS and Windows (through the Windows Subsystem for Linux). It went through several iterations since its initial launch on 2012, which included a collaboration with Guido and mypy to create typeshed, a central repository for type annotations.
Pytype users on public forums have expressed sadness over the discontinuation but generally shared that they understand the reasons behind the decision. Several have also speculated that the writing has been on the wall for quite some time now since members of the Pytype development team were apparently laid off recently.