potential way to handle the bad f64->u64 conversion

Author: gakonst

crates/interledger-service-util/src/exchange_rates_service.rs

@@ -99,9 +99,13 @@ where
 
             match outgoing_amount {
                 Ok(outgoing_amount) => {
-                    // NOTE: If the f64 amount could not fit in a u64, then the
-                    // typecast makes the outgoing amount 0.
-                    request.prepare.set_amount(outgoing_amount as u64);
+                    let outgoing_amount_u64 =
+                        if outgoing_amount != 0.0 && outgoing_amount as u64 == 0 {
+                            std::u64::MAX
+                        } else {
+                            outgoing_amount as u64
+                        };
+                    request.prepare.set_amount(outgoing_amount_u64);
                     trace!("Converted incoming amount of: {} {} (scale {}) from account {} to outgoing amount of: {} {} (scale {}) for account {}",
                         request.original_amount, request.from.asset_code(), request.from.asset_scale(), request.from.id(),
                         outgoing_amount, request.to.asset_code(), request.to.asset_scale(), request.to.id());
@@ -110,11 +114,12 @@ where
                     return Box::new(err(RejectBuilder {
                         code: ErrorCode::F08_AMOUNT_TOO_LARGE,
                         message: format!(
-                            "Could not convert exchange rate from {}:{} to: {}:{}",
+                            "Could not convert exchange rate from {}:{} to: {}:{}. Got incoming amount: {}",
                             request.from.asset_code(),
                             request.from.asset_scale(),
                             request.to.asset_code(),
                             request.to.asset_scale(),
+                            request.prepare.amount(),
                         )
                         .as_bytes(),
                         triggered_by: Some(&self.ilp_address),