From af91c8cd04820e15c383b72305d0a2bac2feccba Mon Sep 17 00:00:00 2001 From: Jan Hicken Date: Fri, 8 Nov 2024 10:24:22 +0100 Subject: [PATCH] gh-126565: Skip `zipfile.Path.exists` check in write mode 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. --- 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 c0e53e273cfaac..5ae16ec970dda4 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.