From dd027bbd285936d0c2d321e6f1ea9909b13dba22 Mon Sep 17 00:00:00 2001
From: Jake Bailey <5341706+jakebailey@users.noreply.github.com>
Date: Mon, 3 Nov 2025 19:16:28 -0800
Subject: [PATCH 1/2] Replace Realpath with more efficient GetFileAttributesEx

---
 internal/vfs/internal/internal.go     | 14 +++++++-------
 internal/vfs/osvfs/os.go              |  4 ++--
 internal/vfs/osvfs/symlink_other.go   | 10 ++++++++++
 internal/vfs/osvfs/symlink_windows.go | 28 +++++++++++++++++++++++++++
 4 files changed, 47 insertions(+), 9 deletions(-)
 create mode 100644 internal/vfs/osvfs/symlink_other.go
 create mode 100644 internal/vfs/osvfs/symlink_windows.go

diff --git a/internal/vfs/internal/internal.go b/internal/vfs/internal/internal.go
index c761e20388..5376a91182 100644
--- a/internal/vfs/internal/internal.go
+++ b/internal/vfs/internal/internal.go
@@ -13,8 +13,8 @@ import (
 )
 
 type Common struct {
-	RootFor  func(root string) fs.FS
-	Realpath func(path string) string
+	RootFor             func(root string) fs.FS
+	IsSymlinkOrJunction func(path string) bool
 }
 
 func RootLength(p string) int {
@@ -93,12 +93,12 @@ func (vfs *Common) GetAccessibleEntries(path string) (result vfs.Entries) {
 			continue
 		}
 
-		if entryType&fs.ModeIrregular != 0 && vfs.Realpath != nil {
-			// Could be a Windows junction. Try Realpath.
-			// TODO(jakebailey): use syscall.Win32FileAttributeData instead
+		if entryType&fs.ModeIrregular != 0 && vfs.IsSymlinkOrJunction != nil {
+			// Could be a Windows junction or other reparse point.
+			// Check using the OS-specific helper.
 			fullPath := path + "/" + entry.Name()
-			if realpath := vfs.Realpath(fullPath); fullPath != realpath {
-				if stat := vfs.Stat(realpath); stat != nil {
+			if vfs.IsSymlinkOrJunction(fullPath) {
+				if stat := vfs.Stat(fullPath); stat != nil {
 					addToResult(entry.Name(), stat.Mode())
 				}
 			}
diff --git a/internal/vfs/osvfs/os.go b/internal/vfs/osvfs/os.go
index d811d6ff71..fd37954693 100644
--- a/internal/vfs/osvfs/os.go
+++ b/internal/vfs/osvfs/os.go
@@ -21,8 +21,8 @@ func FS() vfs.FS {
 
 var osVFS vfs.FS = &osFS{
 	common: internal.Common{
-		RootFor:  os.DirFS,
-		Realpath: osFSRealpath,
+		RootFor:             os.DirFS,
+		IsSymlinkOrJunction: isSymlinkOrJunction,
 	},
 }
 
diff --git a/internal/vfs/osvfs/symlink_other.go b/internal/vfs/osvfs/symlink_other.go
new file mode 100644
index 0000000000..19909e5cf5
--- /dev/null
+++ b/internal/vfs/osvfs/symlink_other.go
@@ -0,0 +1,10 @@
+//go:build !windows
+
+package osvfs
+
+// isSymlinkOrJunction always returns false on non-Windows platforms.
+// On Unix-like systems, symlinks are already properly detected by the
+// fs.ModeSymlink bit in the directory entry type, so this check is not needed.
+func isSymlinkOrJunction(path string) bool {
+	return false
+}
diff --git a/internal/vfs/osvfs/symlink_windows.go b/internal/vfs/osvfs/symlink_windows.go
new file mode 100644
index 0000000000..9a4ffc921d
--- /dev/null
+++ b/internal/vfs/osvfs/symlink_windows.go
@@ -0,0 +1,28 @@
+package osvfs
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// isSymlinkOrJunction checks if the given path is a symlink or junction point
+// on Windows by checking the FILE_ATTRIBUTE_REPARSE_POINT attribute.
+// This is more efficient than calling realpath and comparing paths.
+func isSymlinkOrJunction(path string) bool {
+	pathUTF16, err := syscall.UTF16PtrFromString(path)
+	if err != nil {
+		return false
+	}
+
+	var data syscall.Win32FileAttributeData
+	err = syscall.GetFileAttributesEx(
+		pathUTF16,
+		syscall.GetFileExInfoStandard,
+		(*byte)(unsafe.Pointer(&data)),
+	)
+	if err != nil {
+		return false
+	}
+
+	return data.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT != 0
+}

From 84a02445d1914f6c35193348581cce52560e0847 Mon Sep 17 00:00:00 2001
From: Jake Bailey <5341706+jakebailey@users.noreply.github.com>
Date: Mon, 3 Nov 2025 19:29:40 -0800
Subject: [PATCH 2/2] Nil it out, comment

---
 internal/vfs/osvfs/symlink_other.go   | 5 +----
 internal/vfs/osvfs/symlink_windows.go | 1 -
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/internal/vfs/osvfs/symlink_other.go b/internal/vfs/osvfs/symlink_other.go
index 19909e5cf5..799c60e22f 100644
--- a/internal/vfs/osvfs/symlink_other.go
+++ b/internal/vfs/osvfs/symlink_other.go
@@ -2,9 +2,6 @@
 
 package osvfs
 
-// isSymlinkOrJunction always returns false on non-Windows platforms.
 // On Unix-like systems, symlinks are already properly detected by the
 // fs.ModeSymlink bit in the directory entry type, so this check is not needed.
-func isSymlinkOrJunction(path string) bool {
-	return false
-}
+var isSymlinkOrJunction func(path string) bool
diff --git a/internal/vfs/osvfs/symlink_windows.go b/internal/vfs/osvfs/symlink_windows.go
index 9a4ffc921d..66581fccce 100644
--- a/internal/vfs/osvfs/symlink_windows.go
+++ b/internal/vfs/osvfs/symlink_windows.go
@@ -7,7 +7,6 @@ import (
 
 // isSymlinkOrJunction checks if the given path is a symlink or junction point
 // on Windows by checking the FILE_ATTRIBUTE_REPARSE_POINT attribute.
-// This is more efficient than calling realpath and comparing paths.
 func isSymlinkOrJunction(path string) bool {
 	pathUTF16, err := syscall.UTF16PtrFromString(path)
 	if err != nil {