Close Phase 4 overlay and Unix forwarding gaps

crates/geth-pipe/src/lib.rs

@@ -47,6 +47,18 @@ pub enum PipeError {
     InvalidUnixSocketPath(String),
 }
 
+pub const UNIX_FORWARD_UNSUPPORTED_MESSAGE: &str = "Unix socket forwarding is only supported on Unix platforms; use TCP forwarding on this platform";
+
+#[must_use]
+pub const fn unix_forward_supported() -> bool {
+    cfg!(unix)
+}
+
+#[must_use]
+pub fn unix_forward_unsupported_message() -> &'static str {
+    UNIX_FORWARD_UNSUPPORTED_MESSAGE
+}
+
 pub fn validate_pipe_name(name: &str) -> Result<(), PipeError> {
     if name.is_empty()
         || !name
@@ -124,6 +136,12 @@ mod tests {
         assert!(validate_tcp_forward_target_addr("192.0.2.10:22").is_err());
     }
 
+    #[test]
+    fn unix_forward_support_is_explicit_for_platforms() {
+        assert_eq!(unix_forward_supported(), cfg!(unix));
+        assert!(unix_forward_unsupported_message().contains("Unix socket forwarding"));
+    }
+
     #[test]
     fn unix_forward_paths_must_be_absolute_without_parent_components() {
         assert!(validate_unix_forward_path(Path::new("/tmp/geth.sock")).is_ok());