From ab2dbf2a681c49e8564c73c619629c46dc600792 Mon Sep 17 00:00:00 2001
From: Alan Bateman <alanb@openjdk.org>
Date: Thu, 6 Aug 2026 12:05:18 +0000
Subject: [PATCH] 8389112: (fs) BasicFileAttributes::isDirectory returns false
 for directory in OneDrive over SMB (win)

Reviewed-by: jpai
---
 .../classes/sun/nio/fs/WindowsConstants.java  |  3 ++
 .../sun/nio/fs/WindowsFileAttributes.java     | 54 ++++++++++++-------
 2 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/src/java.base/windows/classes/sun/nio/fs/WindowsConstants.java b/src/java.base/windows/classes/sun/nio/fs/WindowsConstants.java
index d8056f6f2fb..2c91bb01773 100644
--- a/src/java.base/windows/classes/sun/nio/fs/WindowsConstants.java
+++ b/src/java.base/windows/classes/sun/nio/fs/WindowsConstants.java
@@ -75,6 +75,9 @@ class WindowsConstants {
     public static final int IO_REPARSE_TAG_AF_UNIX              = 0x80000023;
     public static final int IO_REPARSE_TAG_MOUNT_POINT          = 0xA0000003;
     public static final int IO_REPARSE_TAG_SYMLINK              = 0xA000000C;
+    public static final int IO_REPARSE_TAG_DEDUP                = 0x80000013;
+    public static final int IO_REPARSE_TAG_CLOUD                = 0x9000001A;
+    public static final int IO_REPARSE_TAG_CLOUD_MASK           = 0x0000F000;
     public static final int MAXIMUM_REPARSE_DATA_BUFFER_SIZE    = 16 * 1024;
     public static final int SYMBOLIC_LINK_FLAG_DIRECTORY        = 0x1;
     public static final int SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE = 0x2;
diff --git a/src/java.base/windows/classes/sun/nio/fs/WindowsFileAttributes.java b/src/java.base/windows/classes/sun/nio/fs/WindowsFileAttributes.java
index 31ea68645ef..0b938bde54c 100644
--- a/src/java.base/windows/classes/sun/nio/fs/WindowsFileAttributes.java
+++ b/src/java.base/windows/classes/sun/nio/fs/WindowsFileAttributes.java
@@ -487,39 +487,57 @@ class WindowsFileAttributes
     }
 
     boolean isDirectoryLink() {
-        return isSymbolicLink() && ((fileAttrs & FILE_ATTRIBUTE_DIRECTORY) != 0);
+        return ((fileAttrs & FILE_ATTRIBUTE_DIRECTORY) != 0)
+                && isReparsePoint()
+                && (reparseTag == IO_REPARSE_TAG_SYMLINK);
     }
 
     boolean isDirectoryJunction() {
-        return reparseTag == IO_REPARSE_TAG_MOUNT_POINT;
+        return ((fileAttrs & FILE_ATTRIBUTE_DIRECTORY) != 0)
+                && isReparsePoint()
+                && (reparseTag == IO_REPARSE_TAG_MOUNT_POINT);
+    }
+
+    boolean isUnixDomainSocket() {
+        return isReparsePoint() && (reparseTag == IO_REPARSE_TAG_AF_UNIX);
     }
 
     @Override
     public boolean isSymbolicLink() {
-        return reparseTag == IO_REPARSE_TAG_SYMLINK;
-    }
-
-    boolean isUnixDomainSocket() {
-        return reparseTag == IO_REPARSE_TAG_AF_UNIX;
+        return isReparsePoint() && (reparseTag == IO_REPARSE_TAG_SYMLINK);
     }
 
     @Override
     public boolean isDirectory() {
-        return ((fileAttrs & FILE_ATTRIBUTE_DIRECTORY) != 0 &&
-                (fileAttrs & FILE_ATTRIBUTE_REPARSE_POINT) == 0);
-    }
-
-    @Override
-    public boolean isOther() {
-        if (isSymbolicLink())
-            return false;
-        // return true if device or reparse point
-        return ((fileAttrs & (FILE_ATTRIBUTE_DEVICE | FILE_ATTRIBUTE_REPARSE_POINT)) != 0);
+        return ((fileAttrs & FILE_ATTRIBUTE_DIRECTORY) != 0)
+                && !isSymbolicLink()
+                && !isDirectoryJunction();
     }
 
     @Override
     public boolean isRegularFile() {
-        return !isSymbolicLink() && !isDirectory() && !isOther();
+        if ((fileAttrs & FILE_ATTRIBUTE_DIRECTORY) != 0)
+            return false;
+        if ((fileAttrs & FILE_ATTRIBUTE_DEVICE) != 0)
+            return false;
+        if (!isReparsePoint())
+            return true;
+
+        // deduplicated file
+        if (reparseTag == IO_REPARSE_TAG_DEDUP)
+            return true;
+
+        // file in cloud storage (Microsoft defines a range of tags for this)
+        if ((reparseTag & ~IO_REPARSE_TAG_CLOUD_MASK) == IO_REPARSE_TAG_CLOUD)
+            return true;
+
+        // socket file or other non-directory reparse point
+        return false;
+    }
+
+    @Override
+    public boolean isOther() {
+        return !isRegularFile() && !isDirectory() && !isSymbolicLink();
     }
 
     @Override