feat(fix-nonce-gap): add support to pending nonce (#728)

* fix-nonce-gap: add support to pending nonce

* small fixes

* move mitm script to script folder

Author: tclemos

cmd/fixnoncegap/fixnoncegap.go

@@ -115,14 +115,12 @@ func fixNonceGap(cmd *cobra.Command, args []string) error {
 	var maxNonce uint64
 	if inputFixNonceGapArgs.maxNonce != 0 {
 		maxNonce = inputFixNonceGapArgs.maxNonce
+		log.Info().Uint64("maxNonce", maxNonce).Msg("maxNonce loaded from --max-nonce flag")
 	} else {
-		maxNonce, err = getMaxNonceFromTxPool(addr)
+		log.Info().Msg("--max-nonce flag not set")
+		maxNonce, err = getMaxNonce(addr)
 		if err != nil {
-			if strings.Contains(err.Error(), "the method txpool_content does not exist/is not available") {
-				log.Error().Err(err).Msg("The RPC doesn't provide access to txpool_content, please check --help for more information about --max-nonce")
-				return nil
-			}
-			log.Error().Err(err).Msg("Unable to get max nonce from txpool")
+			log.Error().Err(err).Msg("Unable to get max nonce, please check --help for more information about --max-nonce")
 			return err
 		}
 	}
@@ -132,7 +130,11 @@ func fixNonceGap(cmd *cobra.Command, args []string) error {
 		log.Info().Stringer("addr", addr).Msg("There is no nonce gap.")
 		return nil
 	}
-	log.Info().Stringer("addr", addr).Msgf("Nonce gap found. Max nonce: %d", maxNonce)
+	log.Info().
+		Stringer("addr", addr).
+		Uint64("currentNonce", currentNonce).
+		Uint64("maxNonce", maxNonce).
+		Msg("Nonce gap found")
 
 	gasPrice, err := rpcClient.SuggestGasPrice(cmd.Context())
 	if err != nil {
@@ -273,6 +275,26 @@ func WaitMineTransaction(ctx context.Context, client *ethclient.Client, tx *type
 	}
 }
 
+func getMaxNonce(addr common.Address) (uint64, error) {
+	log.Info().Msg("getting max nonce from txpool_content")
+	maxNonce, err := getMaxNonceFromTxPool(addr)
+	if err == nil {
+		log.Info().Uint64("maxNonce", maxNonce).Msg("maxNonce loaded from txpool_content")
+		return maxNonce, nil
+	}
+	log.Warn().Err(err).Msg("unable to get max nonce from txpool_content")
+
+	log.Info().Msg("getting max nonce from pending nonce")
+	// if the error is not about txpool_content, falls back to PendingNonceAt
+	maxNonce, err = rpcClient.PendingNonceAt(context.Background(), addr)
+	if err != nil {
+		return 0, err
+	}
+
+	log.Info().Uint64("maxNonce", maxNonce).Msg("maxNonce loaded from pending nonce")
+	return maxNonce, nil
+}
+
 func getMaxNonceFromTxPool(addr common.Address) (uint64, error) {
 	var result PoolContent
 	err := rpcClient.Client().Call(&result, "txpool_content")
@@ -299,6 +321,7 @@ func getMaxNonceFromTxPool(addr common.Address) (uint64, error) {
 			nonceInt, ok := new(big.Int).SetString(nonce, 10)
 			if !ok {
 				err = fmt.Errorf("invalid nonce found: %s", nonce)
+				log.Warn().Err(err).Msg("unable to get txpool_content")
 				return 0, err
 			}
 

scripts/mitm/fake_mitm_override.py

@@ -0,0 +1,38 @@
+# fake_mitm_override_fixed.py
+# this is a mitm proxy script to be used to fake certain JSON-RPC responses from an Ethereum node
+import json, time
+from mitmproxy import http
+
+def _serialize_params(p):
+    if p is None:
+        return None
+    return json.dumps(p, separators=(",", ":"), sort_keys=True)
+
+# keys: (method, params_json_or_None)
+OVERRIDES = {
+    ("txpool_content", None): {"error": {"code": -32601, "message": "Method not found"}},
+    # ("txpool_content", None): {"jsonrpc": "2.0","id": 1,"result": {"pending": {"0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266": {"40": {}}}},
+    # ("eth_getTransactionCount", _serialize_params(["0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266", "latest"])): {"jsonrpc": "2.0", "id": 1, "result": "0xa"},
+    ("eth_getTransactionCount", _serialize_params(["0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266", "pending"])): {"jsonrpc": "2.0", "id": 1, "result": "0x100"},
+}
+
+def request(flow: http.HTTPFlow):
+    body_text = flow.request.get_text()
+    try:
+        j = json.loads(body_text)
+        method = j.get("method")
+        params = j.get("params")
+        req_id = j.get("id")
+        print(f"[{time.time():.3f}] REQ method={method} id={req_id} params={_serialize_params(params)}")
+    except Exception:
+        # malformed JSON: log truncated raw body and let it pass
+        print(f"[{time.time():.3f}] REQ malformed body: {body_text[:200]!r}")
+        return
+
+    key_exact = (method, _serialize_params(params))
+    key_any = (method, None)
+    override = OVERRIDES.get(key_exact) or OVERRIDES.get(key_any)
+    if override is not None:
+        resp = {"jsonrpc": "2.0", "id": req_id}
+        resp.update(override)
+        flow.response = http.Response.make(200, json.dumps(resp), {"Content-Type": "application/json"})