From ab1d6d795fe1e1611529dd2001737c26f72f8dea Mon Sep 17 00:00:00 2001 From: Jan Hicken Date: Sun, 10 Nov 2024 15:57:24 +0100 Subject: [PATCH] gh-126565: Skip `zipfile.Path.exists` check in write mode (GH-126576) When `zipfile.Path.open` is called, the implementation will check whether the path already exists in the ZIP file. However, this check is only required when the ZIP file is in read mode. By swapping arguments of the `and` operator, the short-circuiting will prevent the check from being run in write mode. This change will improve the performance of `open()`, because checking whether a file exists is slow in write mode, especially when the archive has many members. (cherry picked from commit 160758a574d12bf0d965d8206136e7da4f4fd6c3) Co-authored-by: Jan Hicken --- Lib/zipfile/_path/__init__.py | 2 +- .../next/Library/2024-11-08-11-06-14.gh-issue-126565.dFFO22.rst | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) create mode 100644 Misc/NEWS.d/next/Library/2024-11-08-11-06-14.gh-issue-126565.dFFO22.rst diff --git a/Lib/zipfile/_path/__init__.py b/Lib/zipfile/_path/__init__.py index 5079db90648006..b7d4f8906e8bed 100644 --- a/Lib/zipfile/_path/__init__.py +++ b/Lib/zipfile/_path/__init__.py @@ -339,7 +339,7 @@ def open(self, mode='r', *args, pwd=None, **kwargs): if self.is_dir(): raise IsADirectoryError(self) zip_mode = mode[0] - if not self.exists() and zip_mode == 'r': + if zip_mode == 'r' and not self.exists(): raise FileNotFoundError(self) stream = self.root.open(self.at, zip_mode, pwd=pwd) if 'b' in mode: diff --git a/Misc/NEWS.d/next/Library/2024-11-08-11-06-14.gh-issue-126565.dFFO22.rst b/Misc/NEWS.d/next/Library/2024-11-08-11-06-14.gh-issue-126565.dFFO22.rst new file mode 100644 index 00000000000000..22858570bbe03c --- /dev/null +++ b/Misc/NEWS.d/next/Library/2024-11-08-11-06-14.gh-issue-126565.dFFO22.rst @@ -0,0 +1 @@ +Improve performances of :meth:`zipfile.Path.open` for non-reading modes.