Improve performance of name normalization by jaraco · Pull Request #533 · python/importlib_metadata · GitHub
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Improve performance of name normalization #533

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Merged
jaraco merged 7 commits into from
Mar 20, 2026
+52 −2
Merged

Improve performance of name normalization #533

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3e7f3ac
gh-143658: importlib.metadata: Use `str.translate` to improve perform…
hugovk Jan 13, 2026
001db0d
gh-143658: Use `str.lower` and `replace` to further improve performan…
hugovk Feb 6, 2026
852e44f
Remove CPython news fragments.
jaraco Mar 20, 2026
1b0be12
Use parameterize fixture for parameterized tests.
jaraco Mar 20, 2026
a77d0d1
Add performance test for Prepared.normalize.
jaraco Mar 20, 2026
cbadafc
Repeat the operation to get performance visibility.
jaraco Mar 20, 2026
27169dc
Move behavior description into the docstring. Remove references to in…
jaraco Mar 20, 2026
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10 changes: 10 additions & 0 deletions exercises.py
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12 changes: 10 additions & 2 deletions importlib_metadata/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -636,7 +636,8 @@ def _read_files_egginfo_installed(self):
return

paths = (
py311.relative_fix((subdir / name).resolve())
py311
.relative_fix((subdir / name).resolve())
.relative_to(self.locate_file('').resolve(), walk_up=True)
.as_posix()
for name in text.splitlines()
Expand Down Expand Up @@ -928,8 +929,15 @@ def __init__(self, name: str | None):
def normalize(name):
"""
PEP 503 normalization plus dashes as underscores.

Specifically avoids ``re.sub`` as prescribed for performance
benefits (see python/cpython#143658).
"""
return re.sub(r"[-_.]+", "-", name).lower().replace('-', '_')
value = name.lower().replace("-", "_").replace(".", "_")
# Condense repeats
while "__" in value:
value = value.replace("__", "_")
return value

@staticmethod
def legacy_normalize(name):
Expand Down
32 changes: 32 additions & 0 deletions tests/test_api.py
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