Replace eth_getBlockReceipts return type with Opt[T] instead of Optio…

…n[T]

reason:
Option[T] failed to compile when using nim v2
it is related to ref object. But also hard to reproduce outside
combination of nim-json-serialization + nim-json-rpc + something

tests/helpers/handlers.nim

@@ -81,16 +81,10 @@ proc installHandlers*(server: RpcServer) =
     if x != "-1".JsonString:
       result = decodeFromString(x, Quantity)
 
-  when NimMajor >= 2:
-    server.rpc("eth_getBlockReceipts") do(x: JsonString, blockId: RtBlockIdentifier) -> JsonString:
-      # TODO: cannot prove obj is not nil
-      let jsonBytes = JrpcConv.decode(x.string, string)
-      return jsonBytes.JsonString
-  else:
-    server.rpc("eth_getBlockReceipts") do(x: JsonString, blockId: RtBlockIdentifier) -> Option[seq[ReceiptObject]]:
-      if x != "-1".JsonString:
-        let r = decodeFromString(x, Option[seq[ReceiptObject]])
-        return r
+  server.rpc("eth_getBlockReceipts") do(x: JsonString, blockId: RtBlockIdentifier) -> Opt[seq[ReceiptObject]]:
+    if x != "-1".JsonString:
+      let r = decodeFromString(x, Opt[seq[ReceiptObject]])
+      return r
 
   server.rpc("eth_getBlockByNumber") do(x: JsonString, blockId: RtBlockIdentifier, fullTransactions: bool) -> BlockObject:
     var blk: BlockObject

web3/conversions.nim

@@ -14,6 +14,7 @@ import
   faststreams/textio,
   json_rpc/jsonmarshal,
   json_serialization/std/options,
+  json_serialization/stew/results,
   json_serialization,
   ./primitives,
   ./engine_api_types,
@@ -364,6 +365,26 @@ proc writeValue*(w: var JsonWriter[JrpcConv], v: SyncingStatus)
   else:
     w.writeValue(v.syncObject)
 
+# Somehow nim2 refuse to generate automatically
+proc readValue*(r: var JsonReader[JrpcConv], val: var Opt[seq[ReceiptObject]])
+       {.gcsafe, raises: [IOError, SerializationError].} =
+  mixin readValue
+
+  if r.tokKind == JsonValueKind.Null:
+    reset val
+    r.parseNull()
+  else:
+    val.ok r.readValue(seq[ReceiptObject])
+
+proc writeValue*(w: var JsonWriter[JrpcConv], v: Opt[seq[ReceiptObject]])
+      {.gcsafe, raises: [IOError].} =
+  mixin writeValue
+
+  if v.isOk:
+    w.writeValue v.get
+  else:
+    w.writeValue JsonString("null")
+
 func `$`*(v: Quantity): string {.inline.} =
   encodeQuantity(v.uint64)
 

web3/eth_api.nim

@@ -39,7 +39,7 @@ createRpcSigsFromNim(RpcClient):
   proc eth_getTransactionCount(data: Address, blockId: BlockIdentifier): Quantity
   proc eth_getBlockTransactionCountByHash(data: BlockHash): Quantity
   proc eth_getBlockTransactionCountByNumber(blockId: BlockIdentifier): Quantity
-  proc eth_getBlockReceipts(blockId: BlockIdentifier): Option[seq[ReceiptObject]]
+  proc eth_getBlockReceipts(blockId: BlockIdentifier): Opt[seq[ReceiptObject]]
   proc eth_getUncleCountByBlockHash(data: BlockHash): Quantity
   proc eth_getUncleCountByBlockNumber(blockId: BlockIdentifier): Quantity
   proc eth_getCode(data: Address, blockId: BlockIdentifier): seq[byte]