f Acutally only return required features

Author: tnull

lightning/src/ln/features.rs

@@ -802,7 +802,7 @@ impl<T: sealed::Context> Features<T> {
 			};
 
 			if byte & (REQUIRED_FEATURES & unknown_features) != 0 {
-				for bit in 0..8 {
+				for bit in (0..8).step_by(2) {
 					if byte >> bit & 1 == 1 {
 						unknown_bits.push(i * 8 + bit);
 					}
@@ -1070,6 +1070,13 @@ mod tests {
 		assert!(!features.requires_unknown_bits());
 		assert!(features.supports_unknown_bits());
 		assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![]);
+
+		let mut features = ChannelFeatures::empty();
+		features.set_unknown_feature_optional();
+		features.set_custom_bit(123456786).unwrap();
+		assert!(features.requires_unknown_bits());
+		assert!(features.supports_unknown_bits());
+		assert_eq!(features.required_unknown_bits_from(&ChannelFeatures::empty()), vec![123456786]);
 	}
 
 	#[test]