[newlib-cygwin] Cygwin: path_conv: do not get confused by a directory with `.lnk` suffix

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=bd4fdcc0593468237d77035e0f39a0155d17e5bf

commit bd4fdcc0593468237d77035e0f39a0155d17e5bf
Author: Johannes Schindelin <johannes.schindelin@gmx.de>
Date:   Mon Jan 17 21:20:45 2022 +0100

    Cygwin: path_conv: do not get confused by a directory with `.lnk` suffix
    
    When trying to create a directory called `xyz` in the presence of a
    directory `xyz.lnk`, the Cygwin runtime errors out with an `ENOENT`.
    
    The root cause is actually a bit deeper: the `symlink_info::check()`
    method tries to figure out whether the given path refers to a symbolic
    link as emulated via `.lnk` files, but since it is a directory, that is
    not the case, and that hypothesis is rejected.
    
    However, the `fileattr` field is not cleared, so that a later
    `.exists()` call on the instance mistakenly thinks that the symlink
    actually exists. Let's clear that field.
    
    This fixes https://github.com/msys2/msys2-runtime/issues/81
    
    Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Diff:
---
 winsup/cygwin/path.cc | 1 +
 1 file changed, 1 insertion(+)

diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc
index 5ab75f105..87ac2404a 100644
--- a/winsup/cygwin/path.cc
+++ b/winsup/cygwin/path.cc
@@ -3336,6 +3336,7 @@ restart:
 	 hasn't been found. */
       if (ext_tacked_on && !had_ext && (fileattr & FILE_ATTRIBUTE_DIRECTORY))
 	{
+	  fileattr = INVALID_FILE_ATTRIBUTES;
 	  set_error (ENOENT);
 	  continue;
 	}