[New-bugs-announce] [issue38688] Python 3.8 regression: endless loop in shutil.copytree

[Christian Boltz]

New submission from Christian Boltz <python-bugs at cboltz.de>:

The following test script works with Python 3.7 (and older), but triggers an endless loop with Python 3.8:


#!/usr/bin/python3

import shutil
import os

os.mkdir('/dev/shm/t')
os.mkdir('/dev/shm/t/pg')

with open('/dev/shm/t/pg/pol', 'w+') as f:
    f.write('pol')

shutil.copytree('/dev/shm/t/pg', '/dev/shm/t/pg/somevendor/1.0')


The important point is probably that 'pg' gets copied into a subdirectory of itsself. While this worked in Python up to 3.7, doing the same in Python 3.8 runs into an endless loop:

# python3 /home/abuild/rpmbuild/SOURCES/test.py
Traceback (most recent call last):
  File "/home/abuild/rpmbuild/SOURCES/test.py", line 15, in <module> 
    shutil.copytree('/dev/shm/t/pg', '/dev/shm/t/pg/somevendor/1.0')
  File "/usr/lib/python3.8/shutil.py", line 547, in copytree 
    return _copytree(entries=entries, src=src, dst=dst, symlinks=symlinks,
  File "/usr/lib/python3.8/shutil.py", line 486, in _copytree
    copytree(srcobj, dstname, symlinks, ignore, copy_function,
...
    copytree(srcobj, dstname, symlinks, ignore, copy_function,
  File "/usr/lib/python3.8/shutil.py", line 547, in copytree 
    return _copytree(entries=entries, src=src, dst=dst, symlinks=symlinks,
  File "/usr/lib/python3.8/shutil.py", line 449, in _copytree
    os.makedirs(dst, exist_ok=dirs_exist_ok)
  File "/usr/lib/python3.8/os.py", line 206, in makedirs 
    head, tail = path.split(name)
  File "/usr/lib/python3.8/posixpath.py", line 104, in split 
    sep = _get_sep(p)
  File "/usr/lib/python3.8/posixpath.py", line 42, in _get_sep 
    if isinstance(path, bytes):
RecursionError: maximum recursion depth exceeded while calling a Python object

I also reported this at https://bugzilla.opensuse.org/show_bug.cgi?id=1155839

----------
components: Library (Lib)
messages: 355981
nosy: cboltz
priority: normal
severity: normal
status: open
title: Python 3.8 regression: endless loop in shutil.copytree
type: crash
versions: Python 3.8

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue38688>
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