sync_tree turns Windows directory symlinks into file symlinks

[sebastianpoeplau]

When sync_tree is used to copy a directory containing Windows directory symlinks, the resulting copy unexpectedly contains file symlinks instead.

To reproduce the problem, set up a test directory in a Windows shell:

> mkdir test
> mkdir test/real
> cd test
> mklink /D link real
> dir
[...]
 Directory of C:\Users\itmgr\test

07/02/2024  04:07 PM    <DIR>          .
07/03/2024  08:42 AM    <DIR>          ..
07/02/2024  04:06 PM    <SYMLINKD>     link [real]
07/02/2024  04:06 PM    <DIR>          real
[...]

Note that the type of the link is SYMLINKD, indicating a directory link. (This corresponds to the flag SYMBOLIC_LINK_FLAG_DIRECTORY in the Windows API function CreateSymbolicLink.)

Now use sync_tree to copy the directory test somewhere else; the link type changes to SYMLINK:

[...]
 Directory of C:\Users\itmgr\synced

07/02/2024  04:07 PM    <DIR>          .
07/03/2024  08:42 AM    <DIR>          ..
07/02/2024  04:13 PM    <SYMLINK>      link [real]
07/02/2024  04:06 PM    <DIR>          real
[...]

The changed symlink causes the Windows function GetFinalPathNameByHandle to raise API error 123: "The filename, directory name, or volume label syntax is incorrect." The consequence is that the symlink breaks tools using Rust's fs::canonicalize or Python's os.path.realpath(..., strict=True). (The non-strict version of the Python function catches OS error 123 and uses a workaround to still read the link.)

[leocardao]

An MR is under review. I'll come back to you once it's merged. Thank you :)

[thvnx]

Hi, I'm guessing c021846 is a fix for this issue?

Just to let you know that the use of the strictargument in the call to realpath (in src/e3/fs.py) is only available after Python 3.10. The Python version on windows-latest CI machines in GitHub is 3.9.13, so master version of e3-core is no longer easily usable on Windows machines here.

[grouigrokon]

I think this issue is fixec by 8a7832e and c25985f
As for the use of strict parameter, I will make a fix.
I will also add a test to make sure this current issue (#738) is fixed.

[grouigrokon]

FYI, I will mark this issue as fixed. The test added by commit 0148b96 should prove it.

@thvnx , the use of parameter strict is now restricted to python version >= 10 See eda5c83. Thanks for pointing this out !

[thvnx]

Thanks for the quick fix!