shutil.copytree() fails to override existing symbolic links

[SPnRD]

Bug report

Per documentation shutil.copytree() with dirs_exist_ok=True should override all the files. However, shutil.copytree() fails to override existing symbolic links to files in the directory structure.

Resulting error:

*Exception has occurred: Error
[('src/dir/link', 'dst/dir/link', "[Errno 17] File exists: '../top.txt' -> 'dst/dir/link'")]
  File "/home/bdudykevych/projects/89220/BatchScripts/bug.py", line 17, in <module>
    shutil.copytree('src', 'dst', symlinks=True, ignore=None, dirs_exist_ok=True, ignore_dangling_symlinks=True)
shutil.Error: [('src/dir/link', 'dst/dir/link', "[Errno 17] File exists: '../top.txt' -> 'dst/dir/link'")]*

Code to reproduce the issue:

import os
import shutil
#cleanup
if os.path.isdir('src'):
	shutil.rmtree('src')
if os.path.isdir('dst'):
	shutil.rmtree('dst')
os.mkdir('src')
os.mkdir('src/dir')
os.mkdir('dst')
with open('src/top.txt', "w") as constrs:
	constrs.write("dummy")
if not os.path.exists('src/dir/link'):
	if os.path.isfile(os.path.join(os.getcwd(),'src/top.txt')):
		os.symlink('../top.txt', 'src/dir/link')
#Inital copy to empty location. Here it works as there is no link in the destination
shutil.copytree('src', 'dst', symlinks=True, ignore=None, dirs_exist_ok=True, ignore_dangling_symlinks=True)
#2nd launch, fails to override the symlink and results in an error
shutil.copytree('src', 'dst', symlinks=True, ignore=None, dirs_exist_ok=True, ignore_dangling_symlinks=True)

Environment

• Python versions tested on: 3.11.2,
• Operating system : RHEL 7.9 (Maipo), 3.10.0-1160.76.1.el7.x86_64

Linked PRs

• gh-105919 fix shutil.copytree() failing to override existing symbolic links #106893

[terryjreedy]

@SPnRD Use triple backticks ``` above and below code and traceback blocks to format properly, including indents.
I redid both above. Click ... on title bar and select `edit` to see raw text.

[gaitovrat]

@terryjreedy Any progress here?

[athre4t]

@terryjreedy Any progress here?

[terryjreedy]

My participation was strictly as triager helping OP format code.
@giampaolo still active?
One of you should use git blame to see who has worked on shutil more recently than giampaolo. (I likely have never done so.) When found, ping here and request review on the PR.

[gaitovrat]

@barneygale could you review the PR?

[Rid1FZ]

I am also having this issue. This is counter intuitive as in documentation it is said that dirs_exist_ok=True will overwrite anything if exists. But I am getting error where it is not being able to overwrite symlinks to files(I didn't checked symlinks to directories). I am getting similar error saying that file already exists...

---------------------------------------------------------------------------
Error                                     Traceback (most recent call last)
File ~/repos/test/python-test/test.py:3
      1 import shutil
----> 3 shutil.copytree(
      4     "./profile.d",
      5     "./profile.d.bak",
      6     symlinks=True,
      7     dirs_exist_ok=True,
      8     copy_function=shutil.copy2,
      9     ignore_dangling_symlinks=True,
     10 )

File ~/.mamba/lib/python3.12/shutil.py:600, in copytree(src, dst, symlinks, ignore, copy_function, ignore_dangling_symlinks, dirs_exist_ok)
    598 with os.scandir(src) as itr:
    599     entries = list(itr)
--> 600 return _copytree(entries=entries, src=src, dst=dst, symlinks=symlinks,
    601                  ignore=ignore, copy_function=copy_function,
    602                  ignore_dangling_symlinks=ignore_dangling_symlinks,
    603                  dirs_exist_ok=dirs_exist_ok)

File ~/.mamba/lib/python3.12/shutil.py:554, in _copytree(entries, src, dst, symlinks, ignore, copy_function, ignore_dangling_symlinks, dirs_exist_ok)
    552         errors.append((src, dst, str(why)))
    553 if errors:
--> 554     raise Error(errors)
    555 return dst

Error: [('./profile.d/functions.zsh', './profile.d.bak/functions.zsh', "[Errno 17] File exists: 'plugins.sh' -> './profile.d.bak/functions.zsh'"), ('./profile.d/aliases.zsh', './profile.d.bak/aliases.zsh', "[Errno 17] File exists: 'aliases.sh' -> './profile.d.bak/aliases.zsh'"), ('./profile.d/env_vars.zsh', './profile.d.bak/env_vars.zsh', "[Errno 17] File exists: 'env_vars.sh' -> './profile.d.bak/env_vars.zsh'")]