firehose: Try to be more consistent in parsing to address

chain/ethereum/src/codec.rs

@@ -192,19 +192,7 @@ impl<'a> TryInto<web3::types::Transaction> for TransactionTraceAt<'a> {
                     .from
                     .try_decode_proto("transaction from address")?,
             ),
-            to: match self.trace.calls.len() {
-                0 => Some(self.trace.to.try_decode_proto("transaction to address")?),
-                _ => {
-                    match CallType::from_i32(self.trace.calls[0].call_type).ok_or_else(|| {
-                        format_err!("invalid call type: {}", self.trace.calls[0].call_type,)
-                    })? {
-                        CallType::Create => {
-                            None // we don't want the 'to' address on a transaction that creates the contract, to align with RPC behavior
-                        }
-                        _ => Some(self.trace.to.try_decode_proto("transaction to")?),
-                    }
-                }
-            },
+            to: get_to_address(self.trace)?,
             value: self.trace.value.as_ref().map_or(U256::zero(), |x| x.into()),
             gas_price: self.trace.gas_price.as_ref().map(|x| x.into()),
             gas: U256::from(self.trace.gas_limit),
@@ -353,7 +341,7 @@ impl TryInto<EthereumBlockWithCalls> for &Block {
                                     .logs_bloom
                                     .try_decode_proto("transaction logs bloom")?,
                                 from: t.from.try_decode_proto("transaction from")?,
-                                to: Some(t.to.try_decode_proto("transaction to")?),
+                                to: get_to_address(t)?,
                                 transaction_type: None,
                                 effective_gas_price: None,
                             })
@@ -540,3 +528,18 @@ mod test {
         );
     }
 }
+
+fn get_to_address(trace: &TransactionTrace) -> Result<Option<H160>, Error> {
+    // Try to detect contract creation transactions, which have no 'to' address
+    let is_contract_creation = trace.to.len() == 0
+        || trace.calls.get(0).map_or(false, |call| {
+            CallType::from_i32(call.call_type)
+                .map_or(false, |call_type| call_type == CallType::Create)
+        });
+
+    if is_contract_creation {
+        Ok(None)
+    } else {
+        Ok(Some(trace.to.try_decode_proto("transaction to address")?))
+    }
+}