fix(evmrpc): omit notifications from legacy JSON-RPC batch responses per spec

evmrpc/AGENTS.md

@@ -18,7 +18,7 @@ Several `eth_` prefixed endpoints have a `sei_` prefixed counterpart. `eth_` end
 
 The **`sei2`** namespace exposes the same **block** JSON-RPC shape as `sei` blocks, with **bank transfers** included in block payloads (HTTP only). There are seven `sei2_*` methods (block + block receipts + tx counts + `*ExcludeTraceFail` variants); there is no `sei2` transaction or filter API.
 
-Legacy **`sei_*` and `sei2_*`** JSON-RPC (EVM HTTP only) are **gated** by the same `[evm].enabled_legacy_sei_apis` list in `app.toml` (after `deny_list`). Enforcement is **centralized** in `wrapSeiLegacyHTTP` (see `sei_legacy_http.go`): it inspects the JSON-RPC `method` field only. Wired from `HTTPServer.EnableRPC` via `HTTPConfig.SeiLegacyAllowlist` — handlers do not duplicate gate logic. Both surfaces are **deprecated** and scheduled for removal; **only methods named in that array** are allowed. `seid init` / `DefaultConfig` pre-fill the three `sei_*` address/Cosmos helpers; other gated methods (including `sei2_*`) appear **commented** in the generated template. **Docker localnet** (`docker/localnode/config/app.toml`) enables **all** gated methods except **`sei_sign`**. **HTTP 200** for all responses. **Disabled** methods return JSON-RPC `error` code `-32601`, `message` explains not enabled + deprecated, `data` `"legacy_sei_deprecated"`. **Allowed** single-object bodies pass through **unchanged**; JSON **batches** may be subset-forwarded with responses merged by `id`. Optional deprecation signal: HTTP header `Sei-Legacy-RPC-Deprecation` (`SeiLegacyDeprecationHTTPHeader` in `sei_legacy.go`). Coverage: `evmrpc/sei_legacy_test.go` and `integration_test/evm_module/rpc_io_test/testdata/sei_legacy_deprecation/*.iox`.
+Legacy **`sei_*` and `sei2_*`** JSON-RPC (EVM HTTP only) are **gated** by the same `[evm].enabled_legacy_sei_apis` list in `app.toml` (after `deny_list`). Enforcement is **centralized** in `wrapSeiLegacyHTTP` (see `sei_legacy_http.go`): it inspects the JSON-RPC `method` field only. Wired from `HTTPServer.EnableRPC` via `HTTPConfig.SeiLegacyAllowlist` — handlers do not duplicate gate logic. Both surfaces are **deprecated** and scheduled for removal; **only methods named in that array** are allowed. `seid init` / `DefaultConfig` pre-fill the three `sei_*` address/Cosmos helpers; other gated methods (including `sei2_*`) appear **commented** in the generated template. **Docker localnet** (`docker/localnode/config/app.toml`) enables **all** gated methods except **`sei_sign`**. **HTTP 200** for all responses. **Disabled** methods return JSON-RPC `error` code `-32601`, `message` explains not enabled + deprecated, `data` `"legacy_sei_deprecated"`. **Allowed** single-object bodies pass through **unchanged**; JSON **batches** may be subset-forwarded with responses merged by `id` (for requests that include `id`). Per JSON-RPC 2.0, **notifications** (no `id` in the request) do not produce entries in the batch response array, so the merged array is **not** 1:1 with the request batch when notifications are present; if nothing would be returned, the gateway sends an **empty HTTP body** (not `[]`). Optional deprecation signal: HTTP header `Sei-Legacy-RPC-Deprecation` (`SeiLegacyDeprecationHTTPHeader` in `sei_legacy.go`). Coverage: `evmrpc/sei_legacy_test.go` and `integration_test/evm_module/rpc_io_test/testdata/sei_legacy_deprecation/*.iox`.
 
 ## `debug_` prefixed endpoints
 `debug_trace*` endpoints should faithfully replay historical execution. If a transaction encountered an error during its actual execution, a `debug_trace*` call for it should reflect so. If a transction consumed X amount of gas during its actual execution, a `debug_trace*` call should show that exact amount as well.

evmrpc/sei_legacy_http.go

@@ -13,6 +13,11 @@ import (
 // read more than the inner JSON-RPC stack will accept (see rpc.Server.SetHTTPBodyLimit).
 const seiLegacyHTTPMaxBody = 5 * 1024 * 1024
 
+const (
+	invalidRequestCode = -32600
+	internalErrorCode  = -32603
+)
+
 // wrapSeiLegacyHTTP wraps the EVM JSON-RPC HTTP handler to enforce [evm].enabled_legacy_sei_apis for
 // gated sei_* and sei2_* methods. Disallowed calls get a JSON-RPC error without invoking the inner handler.
 // Single-object allowed calls pass through unchanged; batches forward a filtered subset and merge inner
@@ -152,15 +157,8 @@ func (g *seiLegacyHTTPGate) handleBatch(w http.ResponseWriter, r *http.Request,
 		}
 	}
 	if len(forward) == 0 {
-		outArr := make([]json.RawMessage, len(msgs))
-		for i := range msgs {
-			if invalidReq[i] {
-				outArr[i] = json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), -32600, seiLegacyBatchInvalidReqMsg))
-				continue
-			}
-			outArr[i] = json.RawMessage(marshalBlockedResponse(orNullID(ids[i]), blockedErr[i]))
-		}
-		writeJSONArrayResponse(w, http.StatusOK, outArr)
+		outArr := seiLegacyBatchResponsesNoForward(invalidReq, blockedErr, ids, len(msgs))
+		writeJSONRPCBatchResponse(w, http.StatusOK, outArr)
 		return
 	}
 	forwardBody, err := json.Marshal(forward)
@@ -194,15 +192,38 @@ func (g *seiLegacyHTTPGate) handleBatch(w http.ResponseWriter, r *http.Request,
 	if forwardLegacy {
 		w.Header().Set(SeiLegacyDeprecationHTTPHeader, SeiLegacyDeprecationMessage)
 	}
-	writeJSONArrayResponse(w, rec.Code, outArr)
+	writeJSONRPCBatchResponse(w, rec.Code, outArr)
 }
 
 const seiLegacyBatchInternalErr = "invalid or incomplete JSON-RPC batch response from server"
 
 const seiLegacyBatchInvalidReqMsg = "Invalid Request"
 
-// mergeSeiLegacyHTTPBatch builds one response per original batch index: gate errors, -32600 invalid slots,
-// then inner results matched by id (notifications use leftover inner items in order).
+// seiLegacyBatchResponsesNoForward builds the batch JSON-RPC response when nothing is forwarded to the
+// inner server: invalid slots yield -32600, blocked gated methods yield gate errors, and notifications
+// are omitted (JSON-RPC 2.0: no response for notifications, including in batches).
+func seiLegacyBatchResponsesNoForward(
+	invalidReq []bool,
+	blockedErr []error,
+	ids []json.RawMessage,
+	lenMsgs int,
+) []json.RawMessage {
+	out := make([]json.RawMessage, 0, lenMsgs)
+	for i := range lenMsgs {
+		if invalidReq[i] {
+			out = append(out, marshalJSONRPCError(orNullID(ids[i]), invalidRequestCode, seiLegacyBatchInvalidReqMsg))
+			continue
+		}
+		if isJSONRPCNotificationID(ids[i]) {
+			continue
+		}
+		out = append(out, marshalBlockedResponse(orNullID(ids[i]), blockedErr[i]))
+	}
+	return out
+}
+
+// mergeSeiLegacyHTTPBatch merges inner batch results with gate/invalid slots. Output is ordered like the
+// original batch but omits entries for JSON-RPC notifications (no id), per JSON-RPC 2.0 batch rules.
 func mergeSeiLegacyHTTPBatch(
 	invalidReq []bool,
 	blocked []bool,
@@ -211,38 +232,34 @@ func mergeSeiLegacyHTTPBatch(
 	lenMsgs int,
 	innerBody []byte,
 ) []json.RawMessage {
-	outArr := make([]json.RawMessage, lenMsgs)
-	var innerArr []json.RawMessage
-	if err := json.Unmarshal(innerBody, &innerArr); err != nil {
+	appendMergeFailure := func() []json.RawMessage {
+		out := make([]json.RawMessage, 0, lenMsgs)
 		for i := 0; i < lenMsgs; i++ {
 			switch {
 			case invalidReq[i]:
-				outArr[i] = json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), -32600, seiLegacyBatchInvalidReqMsg))
+				out = append(out, json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), invalidRequestCode, seiLegacyBatchInvalidReqMsg)))
+			case isJSONRPCNotificationID(ids[i]):
+				continue
 			case blocked[i]:
-				outArr[i] = json.RawMessage(marshalBlockedResponse(orNullID(ids[i]), blockedErr[i]))
+				out = append(out, json.RawMessage(marshalBlockedResponse(orNullID(ids[i]), blockedErr[i])))
 			default:
-				outArr[i] = json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), -32603, seiLegacyBatchInternalErr))
+				out = append(out, json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), internalErrorCode, seiLegacyBatchInternalErr)))
 			}
 		}
-		return outArr
+		return out
+	}
+
+	var innerArr []json.RawMessage
+	if err := json.Unmarshal(innerBody, &innerArr); err != nil {
+		return appendMergeFailure()
 	}
 
 	entries := make([]json.RawMessage, len(innerArr))
 	idToIdx := make(map[string]int, len(innerArr))
 	for j, raw := range innerArr {
 		idRaw, hasKey, err := jsonRPCObjectIDKey(raw)
 		if err != nil {
-			for i := range lenMsgs {
-				switch {
-				case invalidReq[i]:
-					outArr[i] = json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), -32600, seiLegacyBatchInvalidReqMsg))
-				case blocked[i]:
-					outArr[i] = json.RawMessage(marshalBlockedResponse(orNullID(ids[i]), blockedErr[i]))
-				default:
-					outArr[i] = json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), -32603, seiLegacyBatchInternalErr))
-				}
-			}
-			return outArr
+			return appendMergeFailure()
 		}
 		entries[j] = raw
 		if !hasKey || isJSONRPCNotificationID(idRaw) {
@@ -252,74 +269,38 @@ func mergeSeiLegacyHTTPBatch(
 		if firstIdx, ok := idToIdx[k]; ok {
 			// Duplicate id with different bodies: fail the merge.
 			if !bytes.Equal(entries[firstIdx], raw) {
-				for i := 0; i < lenMsgs; i++ {
-					switch {
-					case invalidReq[i]:
-						outArr[i] = json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), -32600, seiLegacyBatchInvalidReqMsg))
-					case blocked[i]:
-						outArr[i] = json.RawMessage(marshalBlockedResponse(orNullID(ids[i]), blockedErr[i]))
-					default:
-						outArr[i] = json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), -32603, seiLegacyBatchInternalErr))
-					}
-				}
-				return outArr
+				return appendMergeFailure()
 			}
 			continue
 		}
 		idToIdx[k] = j
 	}
 
+	out := make([]json.RawMessage, 0, lenMsgs)
 	used := make([]bool, len(innerArr))
 	for i := 0; i < lenMsgs; i++ {
 		if invalidReq[i] {
-			outArr[i] = json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), -32600, seiLegacyBatchInvalidReqMsg))
-			continue
-		}
-		if blocked[i] {
-			outArr[i] = json.RawMessage(marshalBlockedResponse(orNullID(ids[i]), blockedErr[i]))
-			continue
-		}
-		if !isJSONRPCNotificationID(ids[i]) {
-			k := rpcIDKey(ids[i])
-			idx, ok := idToIdx[k]
-			if !ok || used[idx] {
-				outArr[i] = json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), -32603, seiLegacyBatchInternalErr))
-				continue
-			}
-			used[idx] = true
-			outArr[i] = json.RawMessage(patchJSONRPCResponseIDIfNeeded(entries[idx], ids[i]))
+			out = append(out, json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), invalidRequestCode, seiLegacyBatchInvalidReqMsg)))
 			continue
 		}
-	}
-
-	var fifo []int
-	for j := range entries {
-		if used[j] {
+		if isJSONRPCNotificationID(ids[i]) {
 			continue
 		}
-		fifo = append(fifo, j)
-	}
-
-	notifSlots := make([]int, 0)
-	for i := 0; i < lenMsgs; i++ {
-		if blocked[i] || invalidReq[i] || !isJSONRPCNotificationID(ids[i]) {
+		if blocked[i] {
+			out = append(out, json.RawMessage(marshalBlockedResponse(orNullID(ids[i]), blockedErr[i])))
 			continue
 		}
-		notifSlots = append(notifSlots, i)
-	}
-	fifoPos := 0
-	for _, i := range notifSlots {
-		if fifoPos >= len(fifo) {
-			outArr[i] = json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), -32603, seiLegacyBatchInternalErr))
+		k := rpcIDKey(ids[i])
+		idx, ok := idToIdx[k]
+		if !ok || used[idx] {
+			out = append(out, json.RawMessage(marshalJSONRPCError(orNullID(ids[i]), internalErrorCode, seiLegacyBatchInternalErr)))
 			continue
 		}
-		idx := fifo[fifoPos]
-		fifoPos++
 		used[idx] = true
-		outArr[i] = json.RawMessage(patchJSONRPCResponseIDIfNeeded(entries[idx], ids[i]))
+		out = append(out, json.RawMessage(patchJSONRPCResponseIDIfNeeded(entries[idx], ids[i])))
 	}
 
-	return outArr
+	return out
 }
 
 func rpcIDKey(id json.RawMessage) string {
@@ -388,6 +369,16 @@ func copyHTTPHeader(dst, src http.Header) {
 	}
 }
 
+// writeJSONRPCBatchResponse writes a JSON-RPC batch response. Per JSON-RPC 2.0, if there are no
+// response objects, the server must not return an empty JSON array — use an empty HTTP body instead.
+func writeJSONRPCBatchResponse(w http.ResponseWriter, code int, arr []json.RawMessage) {
+	if len(arr) == 0 {
+		w.WriteHeader(code)
+		return
+	}
+	writeJSONArrayResponse(w, code, arr)
+}
+
 func writeJSONArrayResponse(w http.ResponseWriter, code int, arr []json.RawMessage) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(code)
@@ -407,7 +398,7 @@ func marshalBlockedResponse(id json.RawMessage, gateErr error) []byte {
 			"jsonrpc": "2.0",
 			"id":      id,
 			"error": map[string]interface{}{
-				"code":    -32603,
+				"code":    internalErrorCode,
 				"message": gateErr.Error(),
 			},
 		})