bug#51773: 28.0.60; Issue writing files over WebDAV on MS-Windows

[Ioannis Kappas]

Hi,

There appears to be an issue with Emacs on MS-Windows that prevents
writing to files over WebDAV with the following error message:

  Getting ACLs: Input/output error, //<server>//...//<filename>

To reproduce

1. C-x f to a UNC path or mapped drive pointing to a WebDAV server.
2. Insert some text and C-x s to save the file.
3. The above error message appears, the buffer is still marked as
modified and any other attempt to save the file fails with the same
error.

Analysis to follow.

In GNU Emacs 28.0.60 (build 2, x86_64-w64-mingw32)
 of 2021-11-11
Repository revision: 6dae01ad6da1bcbced062c0d46a6759c7a0570e4
Repository branch: emacs-28
Windowing system distributor 'Microsoft Corp.', version 10