GH-101362: Call join() only when >1 argument supplied to pathlib.PurePath()

[barneygale]

This reduces the time taken to run PurePath("foo") by ~15%

[hauntsaninja]

Looks great! (By far the majority of Paths in the codebases I work on are constructed with a single argument)

[AlexWaygood]

Fantastic work @barneygale! Sorry for the delay on this

[barneygale]

Thanks so much, both! :D

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot s390x SLES 3.x has failed when building commit 3572c86.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/all/#builders/540/builds/4693) and take a look at the build logs.
4. Check if the failure is related to this commit (3572c86) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/all/#builders/540/builds/4693

Summary of the results of the build (if available):

== Tests result: ENV CHANGED ==

415 tests OK.

10 slowest tests:

• test_tools: 3 min 6 sec
• test_concurrent_futures: 2 min 32 sec
• test_multiprocessing_spawn: 2 min 5 sec
• test_asyncio: 1 min 44 sec
• test_math: 1 min 30 sec
• test_multiprocessing_forkserver: 1 min 26 sec
• test_multiprocessing_fork: 1 min 15 sec
• test_signal: 1 min 13 sec
• test_capi: 1 min 5 sec
• test_gdb: 1 min 2 sec

1 test altered the execution environment:
test_asyncio

18 tests skipped:
test_check_c_globals test_devpoll test_ioctl test_kqueue
test_launcher test_msilib test_nis test_peg_generator
test_perf_profiler test_startfile test_tix test_tkinter test_ttk
test_winconsoleio test_winreg test_winsound test_wmi
test_zipfile64

Total duration: 6 min 9 sec

Click to see traceback logs

remote: Enumerating objects: 9, done.        
remote: Counting objects:  12% (1/8)        
remote: Counting objects:  25% (2/8)        
remote: Counting objects:  37% (3/8)        
remote: Counting objects:  50% (4/8)        
remote: Counting objects:  62% (5/8)        
remote: Counting objects:  75% (6/8)        
remote: Counting objects:  87% (7/8)        
remote: Counting objects: 100% (8/8)        
remote: Counting objects: 100% (8/8), done.        
remote: Compressing objects:  16% (1/6)        
remote: Compressing objects:  33% (2/6)        
remote: Compressing objects:  50% (3/6)        
remote: Compressing objects:  66% (4/6)        
remote: Compressing objects:  83% (5/6)        
remote: Compressing objects: 100% (6/6)        
remote: Compressing objects: 100% (6/6), done.        
remote: Total 9 (delta 2), reused 2 (delta 2), pack-reused 1        
From https://github.com/python/cpython
 * branch                  main       -> FETCH_HEAD
Note: switching to '3572c861d8e8f03c34793608e7e2221e116aaec0'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

HEAD is now at 3572c861d8 GH-101362: Call join() only when >1 argument supplied to pathlib.PurePath() (#101665)
Switched to and reset branch 'main'

make: *** [Makefile:1938: buildbottest] Error 3

[AlexWaygood]

Hi! The buildbot s390x SLES 3.x has failed when building commit 3572c86.

From the logs, it looks like this is just test_asyncio being flaky again. Nothing for us to worry about, I don't think :)