f switch to bool for accountable in PendingHTLCInfo and write default

To allow us to get rid of Option<bool>, we just persist false by
default for accountable signals. Moving away from the Option means that
we can't distinguish between no signal being set and a false one, but
we accept this for the sake of simplifying the code.

Author: carlaKC

lightning/src/ln/channelmanager.rs

@@ -429,7 +429,7 @@ pub struct PendingHTLCInfo {
 	pub skimmed_fee_msat: Option<u64>,
 	/// An experimental field indicating whether our node's reputation would be held accountable
 	/// for the timely resolution of the received HTLC.
-	pub incoming_accountable: Option<bool>,
+	pub incoming_accountable: bool,
 }
 
 #[derive(Clone, Debug)] // See FundedChannel::revoke_and_ack for why, tl;dr: Rust bug
@@ -15894,7 +15894,7 @@ impl_writeable_tlv_based!(PendingHTLCInfo, {
 	(8, outgoing_cltv_value, required),
 	(9, incoming_amt_msat, option),
 	(10, skimmed_fee_msat, option),
-	(11, incoming_accountable, option),
+	(11, incoming_accountable, (default_value, false)),
 });
 
 impl Writeable for HTLCFailureMsg {
@@ -19329,7 +19329,7 @@ mod tests {
 		if let Err(crate::ln::channelmanager::InboundHTLCErr { reason, .. }) =
 			create_recv_pending_htlc_info(hop_data, [0; 32], PaymentHash([0; 32]),
 				sender_intended_amt_msat - extra_fee_msat - 1, 42, None, true, Some(extra_fee_msat),
-				None, current_height)
+				false, current_height)
 		{
 			assert_eq!(reason, LocalHTLCFailureReason::FinalIncorrectHTLCAmount);
 		} else { panic!(); }
@@ -19352,7 +19352,7 @@ mod tests {
 		let current_height: u32 = node[0].node.best_block.read().unwrap().height;
 		assert!(create_recv_pending_htlc_info(hop_data, [0; 32], PaymentHash([0; 32]),
 			sender_intended_amt_msat - extra_fee_msat, 42, None, true, Some(extra_fee_msat),
-			None, current_height).is_ok());
+			false, current_height).is_ok());
 	}
 
 	#[test]
@@ -19377,7 +19377,7 @@ mod tests {
 				custom_tlvs: Vec::new(),
 			},
 			shared_secret: SharedSecret::from_bytes([0; 32]),
-		}, [0; 32], PaymentHash([0; 32]), 100, TEST_FINAL_CLTV + 1, None, true, None, None, current_height);
+		}, [0; 32], PaymentHash([0; 32]), 100, TEST_FINAL_CLTV + 1, None, true, None, false, current_height);
 
 		// Should not return an error as this condition:
 		// https://github.com/lightning/bolts/blob/4dcc377209509b13cf89a4b91fde7d478f5b46d8/04-onion-routing.md?plain=1#L334

lightning/src/ln/onion_payment.rs

@@ -249,7 +249,7 @@ pub(super) fn create_fwd_pending_htlc_info(
 pub(super) fn create_recv_pending_htlc_info(
 	hop_data: onion_utils::Hop, shared_secret: [u8; 32], payment_hash: PaymentHash,
 	amt_msat: u64, cltv_expiry: u32, phantom_shared_secret: Option<[u8; 32]>, allow_underpay: bool,
-	counterparty_skimmed_fee_msat: Option<u64>, incoming_accountable: Option<bool>, current_height: u32
+	counterparty_skimmed_fee_msat: Option<u64>, incoming_accountable: bool, current_height: u32
 ) -> Result<PendingHTLCInfo, InboundHTLCErr> {
 	let (
 		payment_data, keysend_preimage, custom_tlvs, onion_amt_msat, onion_cltv_expiry,