From: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Date: Sat, 18 Jan 2025 10:45:18 +0000 (+0100)
Subject: gh-118761: Improve import time for `csv` (#128858)
X-Git-Tag: v3.14.0a5~383
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=d5e9aa690a190bcfa9b43cd3858e26b7b2f72d4f;p=thirdparty%2FPython%2Fcpython.git

gh-118761: Improve import time for `csv` (#128858)

This reduces the import time of the `csv` module by up to five times,
by importing `re` on demand.

In particular, the `re` module is no more implicitly exposed as `csv.re`.
---

diff --git a/Lib/csv.py b/Lib/csv.py
index cd2026598738..0a627ba7a512 100644
--- a/Lib/csv.py
+++ b/Lib/csv.py
@@ -63,7 +63,6 @@ SETTINGS:
         written as two quotes
 """
 
-import re
 import types
 from _csv import Error, writer, reader, register_dialect, \
                  unregister_dialect, get_dialect, list_dialects, \
@@ -281,6 +280,7 @@ class Sniffer:
         If there is no quotechar the delimiter can't be determined
         this way.
         """
+        import re
 
         matches = []
         for restr in (r'(?P<delim>[^\w\n"\'])(?P<space> ?)(?P<quote>["\']).*?(?P=quote)(?P=delim)', # ,".*?",
diff --git a/Misc/NEWS.d/next/Library/2025-01-15-09-45-43.gh-issue-118761.TvAC8E.rst b/Misc/NEWS.d/next/Library/2025-01-15-09-45-43.gh-issue-118761.TvAC8E.rst
new file mode 100644
index 000000000000..38d18b7f4ca0
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-01-15-09-45-43.gh-issue-118761.TvAC8E.rst
@@ -0,0 +1,3 @@
+Reduce the import time of :mod:`csv` by up to five times, by importing
+:mod:`re` on demand. In particular, ``re`` is no more implicitly exposed
+as ``csv.re``. Patch by Bénédikt Tran.