From a2172dc0b913c15eb701e644cf67e2db2a1b7f22 Mon Sep 17 00:00:00 2001
From: Cassondra Foesch <puellanivis@gmail.com>
Date: Thu, 27 Feb 2025 13:51:25 +0000
Subject: [PATCH] short-circuit File.Sync if not supported

---
 client.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/client.go b/client.go
index b747642..73f65cf 100644
--- a/client.go
+++ b/client.go
@@ -2122,6 +2122,13 @@ func (f *File) Sync() error {
 		return os.ErrClosed
 	}
 
+	if data, ok := f.c.HasExtension(openssh.ExtensionFSync().Name); !ok || data != "1" {
+		return &StatusError{
+			Code: sshFxOPUnsupported,
+			msg:  "fsync not supported",
+		}
+	}
+
 	id := f.c.nextID()
 	typ, data, err := f.c.sendPacket(context.Background(), nil, &sshFxpFsyncPacket{
 		ID:     id,