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Important work originally done by @emilyemorehouse two years ago and nearly ready to go in. This bug has affected many people and in some cases has been a dealbreaker to the adoption of the otherwise wonderful pathlib and PEP519. https://stackoverflow.com/questions/33625931/copy-file-with-pathlib-in-python. This adds the outstanding test request from that PR @vstinner (https://github.com/python/cpython/pull/5393). Test fails without the change, passes with it, along with every other test in test_shutil. Some variants were experimented with to make the one line change and the most performant one was picked. # Added Test for PathLike directory destination, the current fail case ``` Lib/test/test_shutil.py::TestMove::test_move_file_pathlike FAILED [100%] ============================================================== FAILURES =============================================================== __________________________________________________ TestMove.test_move_file_pathlike ___________________________________________________ self = <test.test_shutil.TestMove testMethod=test_move_file_pathlike> def test_move_file_pathlike(self): # Move a file to another location on the same filesystem. src = pathlib.Path(self.src_file) > self._check_move_file(src, self.dst_dir, self.dst_file) Lib/test/test_shutil.py:1563: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Lib/test/test_shutil.py:1545: in _check_move_file shutil.move(src, dst) /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/shutil.py:562: in move real_dst = os.path.join(dst, _basename(src)) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ path = PosixPath('/var/folders/r2/psq74t5x3nbfzlph8bh2pvdw0000gn/T/tmp9ie0wh9_/foo') def _basename(path): # A basename() variant which first strips the trailing slash, if present. # Thus we always get the last component of the path, even for directories. sep = os.path.sep + (os.path.altsep or '') > return os.path.basename(path.rstrip(sep)) E AttributeError: 'PosixPath' object has no attribute 'rstrip' /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/shutil.py:526: AttributeError ============================================== 1 failed, 102 deselected in 0.30 seconds =============================================== ``` After change: ``` ========================================================= test session starts ========================================================= platform darwin -- Python 3.7.4, pytest-5.0.1, py-1.8.0, pluggy-0.12.0 -- /Users/maxwellmckinnon/.venvs/TA3.7/bin/python3.7 cachedir: .pytest_cache rootdir: /Users/maxwellmckinnon/dev/cpython plugins: cov-2.7.1, mock-1.10.4 collected 103 items / 102 deselected / 1 selected Lib/test/test_shutil.py::TestMove::test_move_file_pathlike PASSED [100%] ============================================== 1 passed, 102 deselected in 0.06 seconds =============================================== ``` Running all the tests in test_shutil.py ``` ╰─ pytest Lib/test/test_shutil.py -v ========================================================= test session starts ========================================================= platform darwin -- Python 3.7.4, pytest-5.0.1, py-1.8.0, pluggy-0.12.0 -- /Users/maxwellmckinnon/.venvs/TA3.7/bin/python3.7 cachedir: .pytest_cache rootdir: /Users/maxwellmckinnon/dev/cpython plugins: cov-2.7.1, mock-1.10.4 collected 103 items Lib/test/test_shutil.py::TestShutil::test_chown PASSED [ 0%] Lib/test/test_shutil.py::TestShutil::test_copy PASSED [ 1%] ... Lib/test/test_shutil.py::TermsizeTests::test_stty_match SKIPPED [ 99%] Lib/test/test_shutil.py::PublicAPITests::test_module_all_attribute PASSED [100%] ================================================ 96 passed, 7 skipped in 1.25 seconds ================================================= ``` # Performance Considerations Is it considered poor form to get rid of _basename altogether and make use of pathlib in the move function? I'm not sure if the idea is for all these modules to strictly avoid circular dependencies. They are already using os.path which is just as much a citizen in 3.8 as pathlib right? e.g. `real_dst = os.path.join(dst, _basename(src))` becomes `real_dst = Path(dst) / Path(src).name` I've looked around and familiarized myself, and I now think importing pathlib here is fine. My only remaining concern is that of performance. Here's the performance difference for this step. ``` In [46]: %timeit real_dst = os.path.join("a/b/c", _basename('b/')) 2.71 µs ± 62.6 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each) In [47]: %timeit real_dst = Path("a/b/c") / Path('b/').name 12.4 µs ± 65.3 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each) ``` Is 10us significant or insignificant compared to the least expensive operation this function will do? I don't know. Let's find out. ``` In [55]: %timeit os.rename('/tmp/a/a.txt', '/tmp/a/b.txt'); os.rename('/tmp/a/b.txt', '/tmp/a/a.txt') 124 µs ± 2.18 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each) ``` 62us to rename. 10us seems significant enough that we wouldn't want to favor the Path sugar suggestion. 16% speed decrease from adding the 10us. What do people think? I was hoping to get to use pathlib.Path here, but I suspect for this low level move, it should be as fast as possible, and 16% is not worth one line of sugary code to me. https://bugs.python.org/issue32689 Automerge-Triggered-By: @gvanrossum |
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| .. | ||
| NEWS.d | ||
| ACKS | ||
| coverity_model.c | ||
| gdbinit | ||
| HISTORY | ||
| indent.pro | ||
| Porting | ||
| python-config.in | ||
| python-config.sh.in | ||
| python-embed.pc.in | ||
| python-wing3.wpr | ||
| python-wing4.wpr | ||
| python-wing5.wpr | ||
| python.man | ||
| python.pc.in | ||
| README | ||
| README.AIX | ||
| README.coverity | ||
| README.valgrind | ||
| SpecialBuilds.txt | ||
| svnmap.txt | ||
| valgrind-python.supp | ||
| vgrindefs | ||
Python Misc subdirectory
========================
This directory contains files that wouldn't fit in elsewhere. Some
documents are only of historic importance.
Files found here
----------------
ACKS Acknowledgements
gdbinit Handy stuff to put in your .gdbinit file, if you use gdb
HISTORY News from previous releases -- oldest last
indent.pro GNU indent profile approximating my C style
NEWS News for this release (for some meaning of "this")
Porting Mini-FAQ on porting to new platforms
python-config.in Python script template for python-config
python.man UNIX man page for the python interpreter
python.pc.in Package configuration info template for pkg-config
python-wing*.wpr Wing IDE project file
README The file you're reading now
README.AIX Information about using Python on AIX
README.coverity Information about running Coverity's Prevent on Python
README.valgrind Information for Valgrind users, see valgrind-python.supp
SpecialBuilds.txt Describes extra symbols you can set for debug builds
svnmap.txt Map of old SVN revs and branches to hg changeset ids,
help history-digging
valgrind-python.supp Valgrind suppression file, see README.valgrind
vgrindefs Python configuration for vgrind (a generic pretty printer)