Incorrect shutil.copytree() behaviour with symlinks

[76c5dc72-c29b-4d12-862d-ff204cd56a78]

BPO	47049
Nosy	@vajdaz
PRs	python/cpython#31967

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields: ```python assignee = None closed_at = None created_at = labels = ['type-bug', 'library', '3.11'] title = 'Incorrect shutil.copytree() behaviour with symlinks' updated_at = user = 'https://github.com/vajdaz' ``` bugs.python.org fields: ```python activity = actor = 'vajdaz' assignee = 'none' closed = False closed_date = None closer = None components = ['Library (Lib)'] creation = creator = 'vajdaz' dependencies = [] files = [] hgrepos = [] issue_num = 47049 keywords = ['patch'] message_count = 2.0 messages = ['415437', '416700'] nosy_count = 1.0 nosy_names = ['vajdaz'] pr_nums = ['31967'] priority = 'normal' resolution = None stage = 'patch review' status = 'open' superseder = None type = 'behavior' url = 'https://bugs.python.org/issue47049' versions = ['Python 3.11'] ```

[76c5dc72-c29b-4d12-862d-ff204cd56a78]

shutil.copytree incorrectly does not copy symlink contents if called with symlink=False and ignore_dangling_symlinks=True.

The wrong behaviour can be reproduced like this:

$ tree
.
└── a
    ├── a.txt
    └── b
        └── a.txt -> ../a.txt

$ python3 -c "import shutil;shutil.copytree('a/b', 'c', symlinks=False, ignore_dangling_symlinks=True)"

As a result directoy c will be created but it will remain empty. Expected result is a file c/a.txt with the contents of a/b/a.txt.

[76c5dc72-c29b-4d12-862d-ff204cd56a78]

Because I am a first contributor, the automatic quality checks on GitHub have to be manually started by somebody. How can I reqest this and by whom?

[eakr9014]

This still seems to be an issue even though the underlying PR was closed. Even though ignore_dangling_symlinks is passed to recursive calls of copy_tree now, the function will still incorrectly classify symlinks as dangling even if they aren't because it attempts to do a os.readlink relative to the current working directory, not the copied directory

[dabuahoid]

The issue is still present in Python 3.12.5 and must be fixed since copied data with enabled option symlinks=False and ignore_dangling_symlinks=True misses all resolved symbolic links file contents.

[dabuahoid]

Fix in shutil _copytree could look like:

linkPath = linkto if os.path.isabs(linkto) else os.path.join(os.path.dirname(srcname), linkto)
# ignore dangling symlink if the flag is on
if not os.path.exists(linkPath) and ignore_dangling_symlinks: