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Remove unused FVS_* macros #160109
Description
Feature or enhancement
The macros FVS_MASK and FVS_HAVE_SPEC, which are defined in Include/ceval.h, are unused in the cpython code base. They are left over from the removal of the FORMAT_VALUE opcode in python 3.13: they were used to determine if an f-string had a format spec or not. I do not think they need a deprecation period: they were never documented, and any use of them would be unrelated to their original purpose.
I've discussed this with @vstinner who agreed that we don't need a deprecation period.
Has this already been discussed elsewhere?
This is a minor feature, which does not need previous discussion elsewhere
Links to previous discussion of this feature:
No response
Activity
vstinner commentedon Oct 22, 2026
IMO we can remove these macros in Python 3.16. But maybe it would help affected users to document the removal in a Changelog entry (if there are affected users).
anistark commentedon Oct 28, 2026
@ericvsmith I'd like to pick it up if nobody else is already working on it.
vstinner commentedon Nov 4, 2026
@ericvsmith: Do you plan to propose a PR to remove the macros?
moontc commentedon Nov 5, 2026
it seems no one has submitted a PR so far, let me try it
gh-160109: Remove unused FVS macros (#161403)
vstinner commentedon Nov 5, 2026
@moontc: Last week, @anistark already proposed working on a PR. Also, @ericvsmith is a core dev who created the issue, so it would be nice to wait for him to see if he wants to work on a PR. But well, it's not a big deal, the PR is straightforward, I just merged it.
moontc commentedon Nov 5, 2026
@vstinner oh, thanks. you are right, I was indeed a bit hasty, I will keep this in mind from now on. sorry @ericvsmith @anistark ...
ericvsmith commentedon Nov 7, 2026
No problem! I've been tied up on other things. Thanks, all!