rpc/jsonrpc: return InvalidParams for malformed sendRawTransaction RLP

[manusw7]

Summary

SendRawTransaction returns the bare DecodeWrappedTransaction error (rpc/jsonrpc/send_transaction.go:25). Since decode errors don't implement ErrorCode(), the dispatcher (forked from go-ethereum) falls back to errcodeDefault = -32000. Per JSON-RPC 2.0, malformed params should be -32602.

This wires the existing rpc.InvalidParamsError wrapper into the decode path. SendRawTransactionSync delegates to SendRawTransaction (send_transaction.go:97), so the fix applies transitively.

Changes

--- a/rpc/jsonrpc/send_transaction.go
@@ func (api *APIImpl) SendRawTransaction(...)
        txn, err := types.DecodeWrappedTransaction(encodedTx)
        if err != nil {
-               return common.Hash{}, err
+               return common.Hash{}, &rpc.InvalidParamsError{Message: err.Error()}
        }

rpc is already imported; message passes through unchanged.

Why -32602

The -32000 today is a fallback accident, not a deliberate choice. This matches where the spec is heading: execution-apis#817 (fjl: input-validation conditions on submit methods are just "invalid parameters") and #818 (drops the -32000 "Invalid input" group from eth_sendRawTransaction). Reth and Besu already return -32602 for RLP-decode failures; Erigon and geth default to -32000.

Test plan

Added TestSendRawTransaction_InvalidParams_OnMalformedRLP (rpc/jsonrpc/send_transaction_test.go): 5 decode-failure shapes (0xc0, 0xd4, 0x09c0, 0x03c0, 0x04c0), asserting ErrorCode() == -32602 via errors.As. SendRawTransactionSync covered transitively. All pass; make lint clean.

Out of scope

• Decoder message wording — unchanged.
• Non-decode paths (checkTxFee, AllowUnprotectedTxs, chainConfig, txpool Add): not param validation — -32000 stays.

Related

• go-ethereum companion: ethereum/go-ethereum#35129
• Nethermind: NethermindEth/nethermind#11921
• Spec: execution-apis#817, #818

[Copilot]

Pull request overview

Aligns eth_sendRawTransaction JSON-RPC error codes with JSON-RPC 2.0 by returning -32602 (InvalidParams) when the submitted raw transaction cannot be RLP-decoded, instead of falling back to the default -32000.

Changes:

• Wrap types.DecodeWrappedTransaction decode failures in rpc.InvalidParamsError in SendRawTransaction.
• Add a regression test covering multiple malformed-RLP inputs and asserting the returned RPC error code is -32602.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
rpc/jsonrpc/send_transaction.go	Wraps raw-tx decode failures with rpc.InvalidParamsError so the dispatcher emits -32602.
rpc/jsonrpc/send_transaction_test.go	Adds a test suite validating malformed RLP inputs map to InvalidParams error code.

---

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[yperbasis]

The mainnet-rpc-integ-tests failure on this PR is structural, not flaky: the erigontech/rpc-tests fixtures integration/mainnet/eth_sendRawTransaction/test_01..03.json (and integration/arb-sepolia/eth_sendRawTransaction/test_01.json) hardcode "code": -32000 — test_02/test_03 use the same 0xd4 vector as the new unit test. Hence the 9 "diff mismatch" failures (3 fixtures × http/http_comp/websocket).

Required to land:

• A companion rpc-tests PR updating the expected codes to -32602 (messages unchanged), then a new rpc-tests tag and an RPC_VERSION bump in .github/workflows/scripts/rpc_version.env (currently v2.13.0) in this PR, so both land together.
• A decision on the daily geth/nethermind comparison runs (qa-rpc-integration-tests-clients.yml), which use the same fixtures: geth still returns -32000 on the wire (ethereum/go-ethereum#35129 is unmerged), so updating the shared fixtures turns those runs red until upstream catches up.

Nits:

• send_transaction_test.go: the github.com/erigontech/erigon/rpc import is inserted out of alphabetical order (between execution/tests/blockgen and execution/types).
• require := require.New(t) is bound to the parent test but used inside t.Run subtests, so a failing assertion calls FailNow on the parent's t from the subtest goroutine. Bind assertions to the subtest's t instead.

[yperbasis]

mainnet-rpc-integ-tests is red