[3.13] gh-126565: Skip `zipfile.Path.exists` check in write mode (GH-126576) (#126642)

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 <janhicken@users.noreply.github.com>

diff --git a/Lib/zipfile/_path/__init__.py b/Lib/zipfile/_path/__init__.py
index 5079db906480060907d9b5f76355e53bc65f1604..b7d4f8906e8bed046c2015fda042dc7f481a5f2d 100644 (file)
--- a/Lib/zipfile/_path/__init__.py
+++ b/Lib/zipfile/_path/__init__.py
@@ -339,7 +339,7 @@ class Path:
         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 (file)
index 0000000..2285857
--- /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.