Remove overloaded UInt256.fromJson (#74)

* Remove overloaded UInt256.fromJson

Rely instead on UInt256.fromJson from nim-serde, which deserializes an empty string for ?UInt256 into UInt256.none. Previously, empty strings were deserialized into 0.u256. BlockNumber was using this deserialization, and it appears that deserializing a missing block number from a TransactionReceipt into 0 might actually cause some issues when waiting on block confirmations.

* bump version of serde

* Remove "v" from version in `.nimble`

* Fix nimble serde version again ¯\_(ツ)_/¯

ethers.nimble

@@ -9,7 +9,7 @@ requires "chronos >= 4.0.0 & < 4.1.0"
 requires "contractabi >= 0.6.0 & < 0.7.0"
 requires "questionable >= 0.10.2 & < 0.11.0"
 requires "json_rpc >= 0.4.0 & < 0.5.0"
-requires "serde >= 0.1.1 & < 0.2.0"
+requires "serde >= 1.2.1 & < 1.3.0"
 requires "stint"
 requires "stew"
 requires "eth"

ethers/providers/jsonrpc/conversions.nim

@@ -47,11 +47,6 @@ func fromJson(_: type Address, json: JsonNode): ?!Address =
 func `%`*(integer: UInt256): JsonNode =
   %("0x" & toHex(integer))
 
-func fromJson*(_: type UInt256, json: JsonNode): ?!UInt256 =
-  without result =? UInt256.fromHex(json.getStr()).catch, error:
-    return UInt256.failure error.msg
-  success result
-
 # Transaction
 
 # TODO: add option that ignores none Option[T]

testmodule/providers/jsonrpc/testConversions.nim

@@ -26,8 +26,7 @@ suite "JSON Conversions":
     json["number"] = newJString("")
 
     let blk2 = !Block.fromJson(json)
-    check blk2.number.isSome
-    check blk2.number.get.isZero
+    check blk2.number.isNone
 
   test "missing block hash in Block isNone":
 
@@ -78,8 +77,7 @@ suite "JSON Conversions":
     json["blockNumber"] = newJString("")
     without receipt2 =? TransactionReceipt.fromJson(json):
       fail
-    check receipt2.blockNumber.isSome
-    check receipt2.blockNumber.get.isZero
+    check receipt2.blockNumber.isNone
 
   test "missing block hash in TransactionReceipt isNone":
     let json = %*{