ethclient: fix BlockReceipts parameter encoding

[kandrianov]

There is an issue. After marshaling rpc.BlockNumberOrHash we have e.g. {"jsonrpc":"2.0","id":3,"method":"eth_getBlockReceipts","params":[{"blockNumber":"0x2"}]} instead of {"jsonrpc":"2.0","id":3,"method":"eth_getBlockReceipts","params":["0x2"]} and invalid response.

[jsvisa]

thanks, Please also add a test case

[MariusVanDerWijden]

Afaict the method we provide eth_getBlockReceipts will accept both [{"blockNumber":"0x2"}] and ["0x2"] so the marshalling should be okay for geth. Other clients might require the latter form, but I'm not sure

[ajsutton]

Doesn't this change result in block numbers being sent in decimal? ie it winds up executing

go-ethereum/rpc/types.go

Lines 222 to 225 in 9231770

	func (bnh *BlockNumberOrHash) String() string {
	if bnh.BlockNumber != nil {
	return strconv.Itoa(int(*bnh.BlockNumber))
	}

It also seems to be missing the encoding for labels like latest now. So I think this now only works for block hashes.

unit test demonstrating this (add to rpc/types_test.go:

func TestBlockNumberOrHash_WithNumber_StringAndUnmarshal(t *testing.T) {
	tests := []struct {
		name  string
		value BlockNumberOrHash
	}{
		{"max", BlockNumberOrHashWithNumber(math.MaxInt64)},
		{"pending", BlockNumberOrHashWithNumber(PendingBlockNumber)},
		{"latest", BlockNumberOrHashWithNumber(LatestBlockNumber)},
		{"earliest", BlockNumberOrHashWithNumber(EarliestBlockNumber)},
		{"0x20", BlockNumberOrHashWithNumber(32)},
		{"hash", BlockNumberOrHashWithHash(common.Hash{0xaa}, false)},
	}
	for _, test := range tests {
		test := test
		t.Run(test.name, func(t *testing.T) {
			bnh := test.value
			marshalled := []byte("\"" + bnh.String() + "\"")
			var unmarshalled BlockNumberOrHash
			err := json.Unmarshal(marshalled, &unmarshalled)
			if err != nil {
				t.Fatalf("cannot unmarshal (%v): %v", string(marshalled), err)
			}
			if !reflect.DeepEqual(bnh, unmarshalled) {
				t.Fatalf("wrong result: expected %v, got %v", bnh, unmarshalled)
			}
		})
	}
}