feat: add separator to rpc block_results to identify msg & response…

… pair (gnolang#2063)

related to gnolang#2055 

I'm opening this pr to get some ideas.


Currently, keeper does make response data with `\n` as separator to
separate number of responses for single function.

https://github.com/gnolang/gno/blob/80575054429e07c221f1453104dd0ad29e33291c/gno.land/pkg/sdk/vm/keeper.go#L307-L312

If single function returns 2 string, response may look like this
```text
("1" string)
("2" string)
```

However as describe in gnolang#2055, response for single tx with multi-msg
really doesn't separate response values.

So this pr adds `\n\n` as a separator for every function.


### sample contract
```go
package returns

func FuncNo() {}

func Func2() (string, uint64) {
	return "asd", 123
}

func Func3() (int64, string, uint64) {
	return -1, "hmm", 78978
}

```

### call with multi-msg
```javascript
await adena.DoContract({
  messages: [
    {
      "type": "/vm.m_call",
      "value": {
        "caller": "g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5",
        "send": "",
        "pkg_path": "gno.land/r/r3v4/returns",
        "func": "FuncNo",
        "args": []
      }
    },
    {
      "type": "/vm.m_call",
      "value": {
        "caller": "g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5",
        "send": "",
        "pkg_path": "gno.land/r/r3v4/returns",
        "func": "Func2",
        "args": []
      }
    },
    {
      "type": "/vm.m_call",
      "value": {
        "caller": "g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5",
        "send": "",
        "pkg_path": "gno.land/r/r3v4/returns",
        "func": "FuncNo",
        "args": []
      }
    },
    {
      "type": "/vm.m_call",
      "value": {
        "caller": "g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5",
        "send": "",
        "pkg_path": "gno.land/r/r3v4/returns",
        "func": "Func3",
        "args": []
      }
    },
    {
      "type": "/vm.m_call",
      "value": {
        "caller": "g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5",
        "send": "",
        "pkg_path": "gno.land/r/r3v4/returns",
        "func": "FuncNo",
        "args": []
      }
    }
  ],
  gasFee: 1, 
  gasWanted: 2000000
});
```
### block_results from rpc with b64 encoded
```
KCJhc2QiIHN0cmluZykKKDEyMyB1aW50NjQpKC0xIGludDY0KQooImhtbSIgc3RyaW5nKQooNzg5NzggdWludDY0KQ
```
### b64 decoded
```
("asd" string)
(123 uint64)(-1 int64)
("hmm" string)
(78978 uint64)
```
two problem exists with above response
1. It needs to do something about function that doesn't return any value
2. It needs to divide results string for each function


### in this pr response b64 encoded
```
CgooImFzZCIgc3RyaW5nKQooMTIzIHVpbnQ2NCkKCgoKKC0xIGludDY0KQooImhtbSIgc3RyaW5nKQooNzg5NzggdWludDY0KQoKCgo
```

### decode b64 and divide by '\n\n'

![image](https://github.com/gnolang/gno/assets/104744707/cf4ee0b8-a0d3-4fb8-aa59-68c814f8ef5b)
From now, we know...
1. tx had 5 messages
2. first, third and fifth msg function doesn't return anything
3. second msg function return 2 values
4. fourth msg function return 3 values

gno.land/pkg/gnoclient/integration_test.go

@@ -54,7 +54,7 @@ func TestCallSingle_Integration(t *testing.T) {
 	// Execute call
 	res, err := client.Call(baseCfg, msg)
 
-	expected := "(\"hi test argument\" string)"
+	expected := "(\"hi test argument\" string)\n\n"
 	got := string(res.DeliverTx.Data)
 
 	assert.Nil(t, err)
@@ -103,7 +103,7 @@ func TestCallMultiple_Integration(t *testing.T) {
 		Send:     "",
 	}
 
-	expected := "(\"it works!\" string)(\"hi test argument\" string)"
+	expected := "(\"it works!\" string)\n\n(\"hi test argument\" string)\n\n"
 
 	// Execute call
 	res, err := client.Call(baseCfg, msg1, msg2)

gno.land/pkg/sdk/vm/keeper.go

@@ -315,6 +315,7 @@ func (vm *VMKeeper) Call(ctx sdk.Context, msg MsgCall) (res string, err error) {
 			res += "\n"
 		}
 	}
+	res += "\n\n" // use `\n\n` as separator to separate results for single tx with multi msgs
 	return res, nil
 	// TODO pay for gas? TODO see context?
 }

gno.land/pkg/sdk/vm/keeper_test.go

@@ -92,7 +92,7 @@ func Echo(msg string) string {
 	msg2 := NewMsgCall(addr, coins, pkgPath, "Echo", []string{"hello world"})
 	res, err := env.vmk.Call(ctx, msg2)
 	assert.NoError(t, err)
-	assert.Equal(t, `("echo:hello world" string)`, res)
+	assert.Equal(t, `("echo:hello world" string)`+"\n\n", res)
 	// t.Log("result:", res)
 }
 
@@ -235,7 +235,7 @@ func Echo(msg string) string {
 	msg2 := NewMsgCall(addr, coins, pkgPath, "Echo", []string{"hello world"})
 	res, err := env.vmk.Call(ctx, msg2)
 	assert.NoError(t, err)
-	assert.Equal(t, `("echo:hello world" string)`, res)
+	assert.Equal(t, `("echo:hello world" string)`+"\n\n", res)
 }
 
 // Sending too much realm package coins fails.
@@ -331,7 +331,7 @@ func GetAdmin() string {
 	coins := std.MustParseCoins("")
 	msg2 := NewMsgCall(addr, coins, pkgPath, "GetAdmin", []string{})
 	res, err := env.vmk.Call(ctx, msg2)
-	addrString := fmt.Sprintf("(\"%s\" string)", addr.String())
+	addrString := fmt.Sprintf("(\"%s\" string)\n\n", addr.String())
 	assert.NoError(t, err)
 	assert.Equal(t, addrString, res)
 }