gh-127541: Update os.walk example

[totosuki]

I updated the example to exclude __pycache__ directories instead of CVS.
While the issue suggested replacing CVS with .git, a comment pointed out that .git is usually found only in the root directory, making it not equivalent to CVS, which can appear in multiple subdirectories.
On the other hand, __pycache__ directories often appear across various levels of a directory tree, making them a more practical modern example!

• Issue: Update os.walk example to avoid .git subdirs instead of CVS subdirs #127541

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📚 Documentation preview 📚: https://cpython-previews--127765.org.readthedocs.build/

[ghost]

All commit authors signed the Contributor License Agreement.

[picnixz]

See my latest comment: https://github.com/python/cpython/pull/127765/files#r1876269560.

[serhiy-storchaka]

This is a better example. But look also at the fwalk() example and docstrings.

[bedevere-app]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[totosuki]

I have made the requested changes; please review again.

[bedevere-app]

Thanks for making the requested changes!

@serhiy-storchaka: please review the changes made to this pull request.

[serhiy-storchaka]

LGTM.

[totosuki]

Thank you!
You're absolutely right that going into .git isn't ideal. I'll update it to python/Lib/xml now.

[totosuki]

Hi @gpshead , just pinging in case this PR was missed. Appreciate any final review!

[gpshead]

thanks! and good practical idea to use __pycache__ for the example directory to skip.

[miss-islington-app]

Thanks @totosuki for the PR, and @gpshead for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖

[bedevere-app]

GH-131869 is a backport of this pull request to the 3.13 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 FreeBSD Refleaks 3.x (tier-3) has failed when building commit a594998.

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/#/builders/1613/builds/1042) and take a look at the build logs.
4. Check if the failure is related to this commit (a594998) 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/#/builders/1613/builds/1042

Failed tests:

• test.test_concurrent_futures.test_process_pool

Failed subtests:

• test_idle_process_reuse_one - test.test_concurrent_futures.test_process_pool.ProcessPoolSpawnProcessPoolExecutorTest.test_idle_process_reuse_one

Test leaking resources:

• test_process_pool: memory blocks

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

==

Click to see traceback logs

Traceback (most recent call last):
  File "/buildbot/buildarea/3.x.ware-freebsd.refleak/build/Lib/test/test_concurrent_futures/test_process_pool.py", line 146, in test_idle_process_reuse_one
    self.assertEqual(len(executor._processes), 1)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 2 != 1


Traceback (most recent call last):
  File "/buildbot/buildarea/3.x.ware-freebsd.refleak/build/Lib/test/support/__init__.py", line 814, in gc_collect
    gc.collect()
ResourceWarning: unclosed <ssl.SSLSocket fd=6, family=2, type=1, proto=0, laddr=('127.0.0.1', 40156)>
.


Traceback (most recent call last):
  File "/buildbot/buildarea/3.x.ware-freebsd.refleak/build/Lib/test/support/__init__.py", line 814, in gc_collect
    gc.collect()
ResourceWarning: unclosed <ssl.SSLSocket fd=7, family=2, type=1, proto=0, laddr=('127.0.0.1', 46237)>
.


Traceback (most recent call last):
  File "/buildbot/buildarea/3.x.ware-freebsd.refleak/build/Lib/test/support/__init__.py", line 814, in gc_collect
    gc.collect()
ResourceWarning: unclosed <ssl.SSLSocket fd=6, family=2, type=1, proto=0, laddr=('127.0.0.1', 39619)>
.test__all__ (test.test_ftplib.MiscTestCase.test__all__) ... ok

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 CentOS9 NoGIL Refleaks 3.13 (tier-1) has failed when building commit 9ffa80f.

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/#/builders/1605/builds/597) and take a look at the build logs.
4. Check if the failure is related to this commit (9ffa80f) 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/#/builders/1605/builds/597

Failed tests:

• test_free_threading

Test leaking resources:

• test_free_threading: memory blocks

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

==

Click to see traceback logs

remote: Enumerating objects: 7, done.        
remote: Counting objects:  14% (1/7)        
remote: Counting objects:  28% (2/7)        
remote: Counting objects:  42% (3/7)        
remote: Counting objects:  57% (4/7)        
remote: Counting objects:  71% (5/7)        
remote: Counting objects:  85% (6/7)        
remote: Counting objects: 100% (7/7)        
remote: Counting objects: 100% (7/7), done.        
remote: Total 7 (delta 6), reused 7 (delta 6), pack-reused 0 (from 0)        
From https://github.com/python/cpython
 * branch                    3.13       -> FETCH_HEAD
Note: switching to '9ffa80f21edcfec5092388b8b7f3cc7dd29692bb'.

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 9ffa80f21ed [3.13] gh-127541: Update os.walk example (GH-127765) (GH-131869)
Switched to and reset branch '3.13'

configure: WARNING: no system libmpdecimal found; falling back to bundled libmpdecimal (deprecated and scheduled for removal in Python 3.15)

make: *** [Makefile:2240: buildbottest] Error 2

[miss-islington-app]

Thanks @totosuki for the PR, and @gpshead for merging it 🌮🎉.. I'm working now to backport this PR to: 3.12.
🐍🍒⛏🤖

[bedevere-app]

GH-131873 is a backport of this pull request to the 3.12 branch.