From b44f9eefb020da6bcc9b5bb22ec450002d2ee44b Mon Sep 17 00:00:00 2001
From: Roman Khimov <roman@nspcc.ru>
Date: Sat, 16 Oct 2021 21:09:29 +0300
Subject: [PATCH] rpc: correctly handle RPC invocations with no arguments, fix
 #2219

In N3 no arguments passed should be treated as empty arguments array not as
missing array of arguments, because the array must be present even for
functions that accept no parameters.
---
 pkg/rpc/request/txBuilder.go       | 3 +++
 pkg/rpc/request/tx_builder_test.go | 4 ++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/pkg/rpc/request/txBuilder.go b/pkg/rpc/request/txBuilder.go
index f56803428..f8a64b1de 100644
--- a/pkg/rpc/request/txBuilder.go
+++ b/pkg/rpc/request/txBuilder.go
@@ -127,6 +127,9 @@ func CreateFunctionInvocationScript(contract util.Uint160, method string, params
 			emit.Opcodes(script.BinWriter, opcode.PACK)
 		}
 	}
+	if len(params) == 0 {
+		emit.Opcodes(script.BinWriter, opcode.NEWARRAY0)
+	}
 
 	emit.AppCallNoArgs(script.BinWriter, contract, method, callflag.All)
 	return script.Bytes(), nil
diff --git a/pkg/rpc/request/tx_builder_test.go b/pkg/rpc/request/tx_builder_test.go
index c8e6b69ab..9bc6a8214 100644
--- a/pkg/rpc/request/tx_builder_test.go
+++ b/pkg/rpc/request/tx_builder_test.go
@@ -22,10 +22,10 @@ func TestInvocationScriptCreationGood(t *testing.T) {
 		script string
 	}{{
 		ps:     Params{{Type: StringT, Value: "transfer"}},
-		script: "1f0c087472616e736665720c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "c21f0c087472616e736665720c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
 	}, {
 		ps:     Params{{Type: NumberT, Value: 42}},
-		script: "1f0c0234320c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
+		script: "c21f0c0234320c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",
 	}, {
 		ps:     Params{{Type: StringT, Value: "m"}, {Type: BooleanT, Value: true}},
 		script: "11db201f0c016d0c146f459162ceeb248b071ec157d9e4f6fd26fdbe5041627d5b52",