neo-go/pkg/vm/ref_counter_test.go
Roman Khimov 270f0d2d7a vm: fix incorrect refcounting in POPITEM
We're popping an item (array) off the stack, OK, it triggers refs.Remove() for
it. Then we're pushing an inner item to the stack, OK, it triggers refs.Add()
for this element. Why are we removing it afterwards? Looks like something went
wrong in 324107b31e (and https://github.com/nspcc-dev/neo-go/pull/1670)
since a simple test shows zero counter after POPITEM and -1 after popping the
only item left on the stack.

Signed-off-by: Roman Khimov <roman@nspcc.ru>
2024-11-16 18:03:25 +03:00

82 lines
1.7 KiB
Go

package vm
import (
"testing"
"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
"github.com/stretchr/testify/require"
)
func TestRefCounter_Add(t *testing.T) {
r := newRefCounter()
require.Equal(t, 0, int(*r))
r.Add(stackitem.Null{})
require.Equal(t, 1, int(*r))
r.Add(stackitem.Null{})
require.Equal(t, 2, int(*r)) // count scalar items twice
arr := stackitem.NewArray([]stackitem.Item{stackitem.NewByteArray([]byte{1}), stackitem.NewBool(false)})
r.Add(arr)
require.Equal(t, 5, int(*r)) // array + 2 elements
r.Add(arr)
require.Equal(t, 6, int(*r)) // count only array
r.Remove(arr)
require.Equal(t, 5, int(*r))
r.Remove(arr)
require.Equal(t, 2, int(*r))
m := stackitem.NewMap()
m.Add(stackitem.NewByteArray([]byte("some")), stackitem.NewBool(false))
r.Add(m)
require.Equal(t, 5, int(*r)) // map + key + value
r.Add(m)
require.Equal(t, 6, int(*r)) // map only
r.Remove(m)
require.Equal(t, 5, int(*r))
r.Remove(m)
require.Equal(t, 2, int(*r))
}
func TestRefCounterPopItem(t *testing.T) {
prog := makeProgram(opcode.POPITEM)
v := load(prog)
v.estack.PushVal(stackitem.NewArray([]stackitem.Item{stackitem.Make(42)}))
require.Equal(t, 2, int(v.refs))
runVM(t, v)
require.Equal(t, 1, v.estack.Len())
require.Equal(t, 1, int(v.refs))
_ = v.estack.Pop()
require.Equal(t, 0, v.estack.Len())
require.Equal(t, 0, int(v.refs))
}
func BenchmarkRefCounter_Add(b *testing.B) {
a := stackitem.NewArray(nil)
rc := newRefCounter()
b.ResetTimer()
for range b.N {
rc.Add(a)
}
}
func BenchmarkRefCounter_AddRemove(b *testing.B) {
a := stackitem.NewArray([]stackitem.Item{})
rc := newRefCounter()
b.ResetTimer()
for range b.N {
rc.Add(a)
rc.Remove(a)
}
}