From b5b89881b7461f4088b093074667b9618901f502 Mon Sep 17 00:00:00 2001
From: Anna Shaleva <shaleva.ann@nspcc.ru>
Date: Fri, 18 Oct 2024 17:44:25 +0300
Subject: [PATCH] core: prove contract notifications count is not restricted

A part of #3490.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
---
 pkg/core/blockchain_neotest_test.go | 63 +++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/pkg/core/blockchain_neotest_test.go b/pkg/core/blockchain_neotest_test.go
index 22523882b3..dd08846def 100644
--- a/pkg/core/blockchain_neotest_test.go
+++ b/pkg/core/blockchain_neotest_test.go
@@ -43,6 +43,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
 	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
@@ -2697,3 +2698,65 @@ func TestEngineLimits(t *testing.T) {
 	// ProduceLargeObject: hit the limit.
 	cInv.InvokeFail(t, "stack is too big", "produceLargeObject", 500)
 }
+
+// TestRuntimeNotifyRefcounting tries to emit more than MaxStackSize notifications.
+func TestRuntimeNotifyRefcounting(t *testing.T) {
+	const eArgsCount = 500
+
+	bc, acc := chain.NewSingle(t)
+	e := neotest.NewExecutor(t, bc, acc, acc)
+
+	args, _ := strings.CutSuffix(strings.Repeat(`"", `, eArgsCount), `, `)
+	src := fmt.Sprintf(`package test
+		import (
+			"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
+		)
+		// args is an array of LargeEvent parameters containing 500 empty strings.
+		var args = []any{%s};
+		func ProduceNumerousNotifications(count int) {
+			for i := 0; i < count; i++ {
+				runtime.Notify("LargeEvent", args...)
+			}
+		}`, args)
+
+	eParams := make([]compiler.HybridParameter, eArgsCount)
+	for i := range eParams {
+		eParams[i].Name = fmt.Sprintf("str%d", i)
+		eParams[i].Type = smartcontract.ByteArrayType
+	}
+	c := neotest.CompileSource(t, acc.ScriptHash(), strings.NewReader(src), &compiler.Options{
+		Name: "test_contract",
+		ContractEvents: []compiler.HybridEvent{
+			{
+				Name:       "LargeEvent",
+				Parameters: eParams,
+			},
+		},
+	})
+	e.DeployContract(t, c, nil)
+
+	var params = make([]stackitem.Item, eArgsCount)
+	for i := range params {
+		params[i] = stackitem.Make("")
+	}
+	cInv := e.NewInvoker(c.Hash, acc)
+	expected := state.NotificationEvent{
+		ScriptHash: c.Hash,
+		Name:       "LargeEvent",
+		Item:       stackitem.NewArray(params),
+	}
+
+	// ProduceNumerousNotifications: 1 iteration, no limits are hit.
+	h := cInv.Invoke(t, stackitem.Null{}, "produceNumerousNotifications", 1)
+	cInv.CheckTxNotificationEvent(t, h, 0, expected)
+
+	// ProduceNumerousNotifications: vm.MaxStackSize + 1 iterations.
+	count := vm.MaxStackSize + 1
+	h = cInv.Invoke(t, stackitem.Null{}, "produceNumerousNotifications", count)
+	aer, err := e.Chain.GetAppExecResults(h, trigger.Application)
+	require.NoError(t, err)
+	require.Equal(t, count, len(aer[0].Events))
+	for i := range count {
+		require.Equal(t, expected, aer[0].Events[i])
+	}
+}