Prestwich/escalator fixes (#581)

* refactor: handle nonce-too-low cases indicating previous conf.

* feature: add sign_transaction to Middleware trait and fix escalation signing

ethers-middleware/src/signer.rs

@@ -167,6 +167,14 @@ where
         true
     }
 
+    async fn sign_transaction(
+        &self,
+        tx: &TypedTransaction,
+        _: Address,
+    ) -> Result<Signature, Self::Error> {
+        Ok(self.signer.sign_transaction(tx).await.map_err(SignerMiddlewareError::SignerError)?)
+    }
+
     /// Helper for filling a transaction's nonce using the wallet
     async fn fill_transaction(
         &self,

ethers-providers/src/lib.rs

@@ -315,7 +315,7 @@ pub trait Middleware: Sync + Send + Debug {
                 r
             })
             .map(|req| async move {
-                self.sign(req.rlp(chain_id), &self.default_sender().unwrap_or_default())
+                self.sign_transaction(&req, self.default_sender().unwrap_or_default())
                     .await
                     .map(|sig| req.rlp_signed(chain_id, &sig))
             })
@@ -456,6 +456,15 @@ pub trait Middleware: Sync + Send + Debug {
         self.inner().sign(data, from).await.map_err(FromErr::from)
     }
 
+    /// Sign a transaction via RPC call
+    async fn sign_transaction(
+        &self,
+        tx: &TypedTransaction,
+        from: Address,
+    ) -> Result<Signature, Self::Error> {
+        self.inner().sign_transaction(tx, from).await.map_err(FromErr::from)
+    }
+
     ////// Contract state
 
     async fn get_logs(&self, filter: &Filter) -> Result<Vec<Log>, Self::Error> {

ethers-providers/src/pending_escalator.rs

@@ -140,12 +140,19 @@ macro_rules! poll_broadcast_fut {
                 check_all_receipts!($cx, $this);
             }
             Poll::Ready(Err(e)) => {
+                // kludge. Prevents erroring on "nonce too low" which indicates
+                // a previous escalation confirmed during this broadcast attempt
+                if format!("{}", e).contains("nonce too low") {
+                    check_all_receipts!($cx, $this);
+                } else {
                     tracing::error!(
                         error = ?e,
                         "Error during transaction broadcast"
                     );
+
                     completed!($this, Err(e));
                 }
+            }
             Poll::Pending => return Poll::Pending,
         }
     };

ethers-providers/src/provider.rs

@@ -125,6 +125,9 @@ pub enum ProviderError {
 
     #[error("unsupported node client")]
     UnsupportedNodeClient,
+
+    #[error("Attempted to sign a transaction with no available signer. Hint: did you mean to use a SignerMiddleware?")]
+    SignerUnavailable,
 }
 
 /// Types of filters supported by the JSON-RPC.
@@ -517,6 +520,15 @@ impl<P: JsonRpcClient> Middleware for Provider<P> {
             .map_err(|e| ProviderError::CustomError(e.to_string()))?)
     }
 
+    /// Sign a transaction via RPC call
+    async fn sign_transaction(
+        &self,
+        _tx: &TypedTransaction,
+        _from: Address,
+    ) -> Result<Signature, Self::Error> {
+        Err(ProviderError::SignerUnavailable).map_err(FromErr::from)
+    }
+
     ////// Contract state
 
     /// Returns an array (possibly empty) of logs that match the filter