cgo failing interface pointer

cgo_interface_pointer

package main

import (
	. "github.com/tecbot/gorocksdb"
	"fmt"
	"runtime"
)

type TestComparatorHandler struct {
	State string
}

func (self *TestComparatorHandler) Compare(a []byte, b []byte) int {
	return 0
}

func (self *TestComparatorHandler) Name() string {
	return "gorocksdb.test"
}

func main() {
	dbName := "TestDb"

	opts := NewDefaultOptions()
	opts.SetCreateIfMissing(true)

	cmpHandler := &TestComparatorHandler{}
	cmp := NewComparator(cmpHandler)
	opts.SetComparator(cmp)

	DestroyDb(dbName, opts)

	db, err := OpenDb(opts, dbName)
	if err != nil {
		panic(err)
	}
	defer db.Close()

	wo := NewDefaultWriteOptions()
	err = db.Put(wo, []byte("foo"), []byte("bar"))
	if err != nil {
		panic(err)
	}
	fmt.Println("execute GC")
	runtime.GC()
	
	// After call Put the C api will call gorocksdb_comparator_compare
	// and it crashes at the line https://github.com/tecbot/gorocksdb/blob/master/comparator.go#L49
	// with the message "unexpected fault address"
	// If I print the handler I got a panic with SIGILL: illegal instruction
	err = db.Put(wo, []byte("foo"), []byte("foo"))
	if err != nil {
		panic(err)
	}

	ro := NewDefaultReadOptions()
	value, err := db.Get(ro, []byte("foo"))
	if err != nil {
		panic(err)
	}

	fmt.Println(string(value.Data()))
}