f - account for shared input when calculating change

Author: jkczyz

lightning/src/ln/channel.rs

@@ -2960,7 +2960,7 @@ where
 		};
 		let change_value_opt = calculate_change_output_value(
 			&self.funding_negotiation_context,
-			None,
+			shared_funding_input.as_ref().map(|input| input.local_owned()),
 			&shared_funding_output.script_pubkey,
 			&funding_outputs,
 			change_script.minimal_non_dust().to_sat(),

lightning/src/ln/interactivetxs.rs

@@ -1270,6 +1270,10 @@ impl SharedOwnedInput {
 		Self { input, prev_output, local_owned }
 	}
 
+	pub fn local_owned(&self) -> u64 {
+		self.local_owned
+	}
+
 	fn remote_owned(&self) -> u64 {
 		self.prev_output.value.to_sat().saturating_sub(self.local_owned)
 	}