https://github.com/python/cpython/commit/cea2d2475d3eec9f4fd350ef9eb2ba43da1943a5 commit: cea2d2475d3eec9f4fd350ef9eb2ba43da1943a5 branch: main author: Heikki Toivonen <[email protected]> committer: vstinner <[email protected]> date: 2026-01-08T16:28:02+01:00 summary:
gh-143445: Optimize deepcopy for 1.04x speedup (#143449) Gains according to pyperformance: ``` deepcopy: Mean +- std dev: 411 us +- 2 us -> 396 us +- 3 us: 1.04x faster Significant (t=28.94) deepcopy_reduce: Mean +- std dev: 4.38 us +- 0.05 us -> 4.23 us +- 0.04 us: 1.04x faster Significant (t=20.05) ``` Co-authored-by: Bénédikt Tran <[email protected]> files: A Misc/NEWS.d/next/Library/2026-01-05-12-20-42.gh-issue-143445.rgxnbL.rst M Lib/copy.py M Misc/ACKS diff --git a/Lib/copy.py b/Lib/copy.py index fff7e93c2a1b89..4c024ab5311d2d 100644 --- a/Lib/copy.py +++ b/Lib/copy.py @@ -230,7 +230,7 @@ def _reconstruct(x, memo, func, args, *, deepcopy=deepcopy): deep = memo is not None if deep and args: - args = (deepcopy(arg, memo) for arg in args) + args = [deepcopy(arg, memo) for arg in args] y = func(*args) if deep: memo[id(x)] = y diff --git a/Misc/ACKS b/Misc/ACKS index 671fcf88c75af9..63ddfb89071c0b 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -1931,6 +1931,7 @@ James Tocknell Bennett Todd R Lindsay Todd Eugene Toder +Heikki Toivonen Erik Tollerud Stephen Tonkin Matias Torchinsky diff --git a/Misc/NEWS.d/next/Library/2026-01-05-12-20-42.gh-issue-143445.rgxnbL.rst b/Misc/NEWS.d/next/Library/2026-01-05-12-20-42.gh-issue-143445.rgxnbL.rst new file mode 100644 index 00000000000000..f5dea2e49afe2a --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-01-05-12-20-42.gh-issue-143445.rgxnbL.rst @@ -0,0 +1 @@ +Speed up :func:`copy.deepcopy` by 1.04x. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
