gh-143658: Use str.lower and replace to further improve performance of importlib.metadata.Prepared.normalized

[hugovk]

Follow on from #143660 which replaced re.sub with str.translate.

@henryiii discovered that whilst that is an improvement on Python 3.10-3.11 and 3.14, the performance of str.translate is much worse on Python 3.12 and 3.13, and can be worse than the original re.sub.

Further, his fix in pypa/packaging#1064 to replace str.translate with str.lower and str.replace calls is better than both the other options across all Python versions, to varying degrees.

I benchmarked all three across all available Python Build Standalone versions from 3.10-3.15 on macOS:

I also benchmarked Windows and Ubuntu it's the same pattern.

Whilst the improvement isn't as large for CPython 3.15 as it is for libraries such as packaging that support a wide range of Pythons, importlib.metadata does have a backport, and I'll update python/importlib_metadata#529 once this is merged.

• Issue: importlib.metadata: Use str.translate to improve performance of importlib.metadata.Prepared.normalized #143658

[hugovk]

Attached code for benchmarking and making the chart, and the results data from my macOS machine:

bench.zip

And charts and data of benchmarking on macOS, Ubuntu and Windows via GitHub Actions:

macos-ubuntu-windows.zip

[sergey-miryanov]

LGTM

[hugovk]

This packaging change has been in version 26.0 for 16 days now with 306,207,835 downloads no problems, let's merge :)

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 FreeBSD Refleaks 3.x (tier-3) has failed when building commit 28fb13c.

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/2796) and take a look at the build logs.
4. Check if the failure is related to this commit (28fb13c) 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/2796

Test leaking resources:

• test_events: memory blocks
• test_events: references

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/support/__init__.py", line 947, in gc_collect
    gc.collect()
    ~~~~~~~~~~^^
ResourceWarning: unclosed <socket.socket fd=9, family=2, type=1, proto=6, laddr=('127.0.0.1', 20202), raddr=('127.0.0.1', 20203)>
Task was destroyed but it is pending!
task: <Task pending name='Task-2918' coro=<BaseSelectorEventLoop._accept_connection2() done, defined at /buildbot/buildarea/3.x.ware-freebsd.refleak/build/Lib/asyncio/selector_events.py:217> wait_for=<Future pending cb=[Task.task_wakeup()]>>
Warning -- Unraisable exception
Exception ignored while calling deallocator <function _SelectorTransport.__del__ at 0x8470965d0>:
Traceback (most recent call last):
  File "/buildbot/buildarea/3.x.ware-freebsd.refleak/build/Lib/asyncio/selector_events.py", line 873, in __del__
    _warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
    ~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ResourceWarning: unclosed transport <_SelectorSocketTransport closing fd=9>
k


Traceback (most recent call last):
  File "/buildbot/buildarea/3.x.ware-freebsd.refleak/build/Lib/test/support/__init__.py", line 947, in gc_collect
    gc.collect()
    ~~~~~~~~~~^^
ResourceWarning: unclosed <socket.socket fd=10, family=2, type=1, proto=6, laddr=('127.0.0.1', 14643), raddr=('127.0.0.1', 14644)>
Task was destroyed but it is pending!
task: <Task pending name='Task-98' coro=<BaseSelectorEventLoop._accept_connection2() done, defined at /buildbot/buildarea/3.x.ware-freebsd.refleak/build/Lib/asyncio/selector_events.py:217> wait_for=<Future pending cb=[Task.task_wakeup()]>>
Warning -- Unraisable exception
Exception ignored while calling deallocator <function _SelectorTransport.__del__ at 0x8428925d0>:
Traceback (most recent call last):
  File "/buildbot/buildarea/3.x.ware-freebsd.refleak/build/Lib/asyncio/selector_events.py", line 873, in __del__
    _warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
    ~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ResourceWarning: unclosed transport <_SelectorSocketTransport closing fd=10>
k