LWPCookieJar.save() gives unexpected results in 3.11.0

[sebdelsol]

Bug report

LWPCookieJar.save() doesn't truncate the file.
So removing cookies from an existing jar file then saving it gives unexpected results :

from http.cookiejar import LWPCookieJar
from urllib.request import Request, urlopen

lwp = LWPCookieJar("cookies.lwp")

# get some cookies & save
request = Request("https://www.scoopmeacookie.com/give-me-more/")
with urlopen(request) as response:
 lwp.extract_cookies(response, request)
# here's some cookies
print(f"Extracted : {lwp}")
lwp.save()

# clear the jar & save
lwp.clear()
# the jar is now empty
print(f"Clear : {lwp}")
lwp.save()

# are those cookies really gone ?
lwp.load()
# they're back ! that would be great IRL
# LWPCookieJar.save() didn't truncate the file (os.O_TRUNC is missing)
print(f"Reload : {lwp}")

Environment

• Python 3.11.0 (main, Oct 24 2022, 18:26:48) [MSC v.1933 64 bit (AMD64)]
• Windows 10 64 bits 22H2

Linked PRs

• gh-99576: Fix cookiejar file that was not truncated for some classes #99616
• [3.11] gh-99576: Fix cookiejar file that was not truncated for some classes (GH-99616) #100377

[ambv]

Fixed for release in 3.11.2 and 3.12.0.

[ambv]

Thanks for the fix, @sobolevn! ✨ 🍰 ✨