From b377e2cdc9248e2559d1d9f76512b7aaeaac27bb Mon Sep 17 00:00:00 2001
From: Chris Lu <chrislusf@users.noreply.github.com>
Date: Thu, 22 Oct 2026 08:12:24 -0700
Subject: [PATCH] fuse integration: detect WinFsp mounts on Windows in
 mountedAt

A directory mount is a reparse point and a drive mount is a volume root; a plain directory is now refused instead of accepted.
---
 test/fuse_integration/mounted_unsupported.go |  2 +-
 test/fuse_integration/mounted_windows.go     | 34 ++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 test/fuse_integration/mounted_windows.go

diff --git a/test/fuse_integration/mounted_unsupported.go b/test/fuse_integration/mounted_unsupported.go
index c288b8c2e1..1d698e5241 100644
--- a/test/fuse_integration/mounted_unsupported.go
+++ b/test/fuse_integration/mounted_unsupported.go
@@ -1,4 +1,4 @@
-//go:build !unix
+//go:build !unix && !windows
 
 package fuse
 
diff --git a/test/fuse_integration/mounted_windows.go b/test/fuse_integration/mounted_windows.go
new file mode 100644
index 0000000000..4a8d199b3a
--- /dev/null
+++ b/test/fuse_integration/mounted_windows.go
@@ -0,0 +1,34 @@
+//go:build windows
+
+package fuse
+
+import (
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+// deviceID has no portable meaning here: reporting one device keeps
+// waitForMount from mistaking the plain pre-mount directory for a live mount.
+func deviceID(path string) (uint64, error) {
+	return 0, nil
+}
+
+// mountedAt reports whether path is a WinFsp mount: a directory mount is a
+// reparse point and a drive mount is a volume root, while a plain directory
+// is neither.
+func mountedAt(path string) bool {
+	abs, err := filepath.Abs(path)
+	if err != nil {
+		return false
+	}
+	if filepath.Dir(abs) == abs {
+		return true
+	}
+	info, err := os.Lstat(abs)
+	if err != nil {
+		return false
+	}
+	data, ok := info.Sys().(*syscall.Win32FileAttributeData)
+	return ok && data.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT != 0
+}