[mypyc] Enable free threading when compiling multiple modules #19541
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
p-sawicki
approved these changes
Jul 30, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Previously we used multi-phase initialization to enable free threading on Python builds that support it, but only if a single module was compiled in a group.
Implements it also for multiple modules in a group. Add support for multi-phase initialization in module shims and the shared library. It's still only used on free-threaded builds, and we fall back to the old approach on other Python versions/builds.
This enables compiling mypy and mypyc on free-threaded Python builds. At least almost all mypy and mypyc tests now pass when compiled and on 3.14.0b4 with free threading (only tested on macOS so far).