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Commit35d8ac7

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GH-120754: Disable buffering in Path.read_bytes (#122111)
`Path.read_bytes()` is used to read a whole file. buffering /BufferedIO is focused around making small, possibly interleaved,read/write efficient which doesn't add value in this case.On my Mac, running the benchmark:```pythonimport pyperffrom pathlib import Pathdef read_all(all_paths): for p in all_paths: p.read_bytes()def read_file(path_obj): path_obj.read_bytes()all_rst = list(Path("Doc").glob("**/*.rst"))all_py = list(Path(".").glob("**/*.py"))assert all_rst, "Should have found rst files"assert all_py, "Should have found python source files"runner = pyperf.Runner()runner.bench_func("read_file_small", read_file, Path("Doc/howto/clinic.rst"))runner.bench_func("read_file_large", read_file, Path("Doc/c-api/typeobj.rst"))```before:```python.....................read_file_small: Mean +- std dev: 6.80 us +- 0.07 us.....................read_file_large: Mean +- std dev: 10.8 us +- 0.2 us````after:```python.....................read_file_small: Mean +- std dev: 5.67 us +- 0.05 us.....................read_file_large: Mean +- std dev: 9.77 us +- 0.52 us```
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‎Lib/pathlib/_abc.py

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@@ -585,7 +585,7 @@ def read_bytes(self):
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"""
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Open the file in bytes mode, read it, and close the file.
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"""
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withself.open(mode='rb')asf:
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withself.open(mode='rb',buffering=0)asf:
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returnf.read()
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defread_text(self,encoding=None,errors=None,newline=None):

‎Lib/test/test_pathlib/test_pathlib_abc.py

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@@ -1464,7 +1464,7 @@ def stat(self, *, follow_symlinks=True):
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defopen(self,mode='r',buffering=-1,encoding=None,
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errors=None,newline=None):
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ifbuffering!=-1:
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ifbuffering!=-1andnot (buffering==0and'b'inmode):
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raiseNotImplementedError
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path_obj=self.resolve()
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path=str(path_obj)
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``Pathlib.read_bytes`` no longer opens the file in Python's buffered I/O mode. This reduces overheads as the code reads a file in whole leading to a modest speedup.

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