mypy 2.x for Debian ------------------- Mypy 2.x include a rust-based native parser that is not yet packaged in Debian. Until that library is packaged [1], the Debian package of mypy 2.x does not have both the native parser and parallel parsing features, and their command-line options (`--native-parser`, `--num-workers`) are silently accepted and ignored. The parallel parsing feature requires the native parser, so it had to also be disabled. [1] The mypy native parsing Python library "ast_serialize" requires private Rust crates from "ruff" that are not published independently (on crates.io or similar) nor distributed (vendored) by ast_serialize itself. The Debian package for ruff[2] is quite behind the version pinned by ast_serialize and is currently (2026-05-15) not even in Debian's "testing" distribution. Additionally, it is likely that whatever is blocking the ruff packagers from upgrading to more recent releases would be a challenge for packaging the specific private crates needed by ast_serialize. https://github.com/mypyc/ast_serialize/issues/49 https://bugs.debian.org/1074734 Latest update on ruff packaging [2] https://tracker.debian.org/pkg/ruff -- Michael R. Crusoe , Fri, 15 May 2026 12:09:17 +0200