bpo-43012: remove pathlib._Accessor by barneygale · Pull Request #25701 · python/cpython (original) (raw)

Bravo! I didn't realize yesterday with #25699 that it was temp code. I had seen your commits and misunderstood. I thought somehow your intent was to add a class in between Path and PurePath which leveraged moving all cwd, resolve, open, touch, into the accessor.

I had done some performance testing that move of cwd, resolve, open, touch into the accessor and noted that it resulted in a significant slow down doing so.

cwd()
python3.9 -m timeit -r 5 -n 100000 -s 'from pathlib import Path' 'Path.cwd()'
100000 loops, best of 5: 4.03 usec per loop
python3.10-with-accessor -m timeit -r 5 -n 100000 -s 'from pathlib import Path' 'Path.cwd()'
100000 loops, best of 5: 206 usec per loop

resolve()
python3.9 -m timeit -r 5 -n 50000 -s 'from pathlib import PosixPath' -s 'p = PosixPath("/usr/bin/python")' 'p.resolve()'
50000 loops, best of 5: 15.4 usec per loop
python3.10-with-accessor -m timeit -r 5 -n 50000 -s 'from pathlib import PosixPath' -s 'p = PosixPath("/usr/bin/python")' 'p.resolve()'
50000 loops, best of 5: 429 usec per loop

open()
python3.9 -m timeit -r 5 -n 100000 -s 'from pathlib import PosixPath' -s 'p = PosixPath("/var/tmp/tmpfile.txt")' 'with open(p, "w"): pass'
100000 loops, best of 5: 14 usec per loop
python3.10-with-accessor -m timeit -r 5 -n 100000 -s 'from pathlib import PosixPath' -s 'p = PosixPath("/var/tmp/tmpfile.txt")' 'with open(p, "w"): pass'
100000 loops, best of 5: 163 usec per loop

touch()
python3.9 -m timeit -r 5 -n 100000 -s 'from pathlib import PosixPath' -s 'p = PosixPath("/var/tmp/tmpfile.txt")' 'p.touch()'
100000 loops, best of 5: 1.89 usec per loop
python3.10-with-accessor -m timeit -r 5 -n 100000 -s 'from pathlib import PosixPath' -s 'p = PosixPath("/var/tmp/tmpfile.txt")' 'p.touch()'
100000 loops, best of 5: 26.1 usec per loop

I have to imagine that moving everything out will do the exact opposite and make all of these slow down go away and speed up all of the other functions that had used the accessor. That said, I'm just a guy out there who happens to be using pathlib, but I think this is brilliant.

Myself, I had been wondering about changing the name of accessor to common (or something similar) having also seen Pitrou's comment to you, since it seemed like a vestigial abstraction. But I like taking it out entirely even better. Remove the cruft and make it faster - this seems like a win!