Marshal, unmarshal. Problems with zero and null data and values.

[illia-li]

Explanation according to the cassandra protocol:
row is composed of value_1...value_n where n is columns_count.
value is a bytes representing the value.
bytes - a int n, followed by n bytes if n >= 0.
If n = 0, no byte should follow and the value represented is zero.
If n < 0, no byte should follow and the value represented is null.

Explanation of the current situation in gocql:
Marshalling: for almost all types:
The zero value is marshaled into a slice with a length equal to the length of the type filled with zeros.
example: zero values of TypeInt marshaled into []byte{0,0,0,0}.
The null values marshaled correctly, with some assumptions.
Unmarshalling: for almost all types, the zero and null data is unmarshaled into zero values.

Explanation of the current situation in cassanda:
The following behavioral features were found:

1. On INSERT zero data into columns with types tinyint, smallint, date, time, duration - db returns error.
2. On SELECT zero values from columns with types tinyint, smallint, date, time, duration - db returns data filled with zeros (with not zero len) .
3. On SELECT zero values from columns with types list, set, map, ascii, blob, text, timeuuid, uuid, varchar- db returns null data (with len -1) .
   Types udt and tuple need to check.

Explanation of the current situation in scylla:
The following behavioral features were found:

1. On INSERT zero data into columns with type duration - db returns error.
2. On SELECT zero values from columns with type duration - db returns data filled with zeros (with not zero len) .
3. On SELECT zero values from columns with types list, set, map, ascii, blob, text, timeuuid, uuid, varchar- db returns null data (with len -1) .
   Types udt and tuple need to check.

Test code for Marshal zero values:

func TestMarshalZeroValues(t *testing.T) {
	type tCase struct {
		Type  TypeInfo
		Value interface{}
	}

	tCases := []tCase{
		{Type: NativeType{proto: 2, typ: TypeBoolean}, Value: false},
		{Type: NativeType{proto: 2, typ: TypeTinyInt}, Value: int(0)},
		{Type: NativeType{proto: 2, typ: TypeSmallInt}, Value: int(0)},
		{Type: NativeType{proto: 2, typ: TypeInt}, Value: int(0)},
		{Type: NativeType{proto: 2, typ: TypeBigInt}, Value: int(0)},
		{Type: NativeType{proto: 2, typ: TypeVarint}, Value: int(0)},
		{Type: NativeType{proto: 2, typ: TypeFloat}, Value: float32(0)},
		{Type: NativeType{proto: 2, typ: TypeDouble}, Value: float64(0)},
		{Type: NativeType{proto: 2, typ: TypeDecimal}, Value: inf.Dec{}},
		{Type: NativeType{proto: 2, typ: TypeInet}, Value: make(net.IP, 0)},
		{Type: NativeType{proto: 2, typ: TypeUUID}, Value: UUID{}},
		{Type: NativeType{proto: 2, typ: TypeTimeUUID}, Value: UUID{}},
		{Type: NativeType{proto: 2, typ: TypeTime}, Value: int64(0)},
		{Type: NativeType{proto: 2, typ: TypeDate}, Value: int64(0)},
		{Type: NativeType{proto: 2, typ: TypeDuration}, Value: time.Duration(0)},
		{Type: NativeType{proto: 2, typ: TypeTimestamp}, Value: int64(0)},
		{Type: NativeType{proto: 2, typ: TypeText}, Value: ""},
		{Type: NativeType{proto: 2, typ: TypeAscii}, Value: ""},
		{Type: NativeType{proto: 2, typ: TypeBlob}, Value: ""},
		{Type: NativeType{proto: 2, typ: TypeVarchar}, Value: ""},

		{
			Type: CollectionType{
				NativeType: NativeType{proto: 2, typ: TypeList},
				Elem:       NativeType{proto: 2, typ: TypeSmallInt},
			},
			Value: make([]byte, 0)},
		{
			Type: CollectionType{
				NativeType: NativeType{proto: 2, typ: TypeSet},
				Elem:       NativeType{proto: 2, typ: TypeSmallInt},
			},
			Value: make([]byte, 0)},
		{
			Type: CollectionType{
				NativeType: NativeType{proto: 2, typ: TypeMap},
				Key:        NativeType{proto: 2, typ: TypeSmallInt},
				Elem:       NativeType{proto: 2, typ: TypeSmallInt},
			},
			Value: make(map[int]int)},
		{
			Type: UDTTypeInfo{
				NativeType: NativeType{proto: 3, typ: TypeUDT},
				KeySpace:   "",
				Name:       "test_udt",
				Elements: []UDTField{
					{Name: "1", Type: NativeType{proto: 2, typ: TypeSmallInt}},
				},
			},
			Value: map[string]interface{}{},
		},
		{
			Type: TupleTypeInfo{
				NativeType: NativeType{proto: 3, typ: TypeTuple},
				Elems: []TypeInfo{
					NativeType{proto: 2, typ: TypeSmallInt},
				},
			},
			Value: []interface{}{},
		},
	}

	errs := make([]string, 0)
	mData := make([]string, 0)
	for _, c := range tCases {
		data, err := Marshal(c.Type, c.Value)
		if err != nil {
			errs = append(errs, fmt.Sprintf("type:<%s>\t-\terror: %s", c.Type.Type(), err.Error()))
		} else if len(data) != 0 {
			mData = append(mData, fmt.Sprintf("type:<%s>\t-\tdata: <%#v>", c.Type.Type(), data))
		}
	}

	if len(errs) != 0 {
		t.Errorf("\nMarshaling of %d cases, have %d errors:\n%s", len(tCases), len(errs), strings.Join(errs, "\n"))
	}
	if len(mData) != 0 {
		t.Errorf("\nMarshaling of %d cases, have %d a non zero data:\n%s", len(tCases), len(mData), strings.Join(mData, "\n"))
	}
}

Output:

=== RUN   TestMarshalZeroValues
    marshal_0_all_test.go:226: 
        Marshaling of 25 cases, have 1 errors:
        type:<tuple>	-	error: cannont marshal tuple: wrong number of elements
    marshal_0_all_test.go:229: 
        Marshaling of 25 cases, have 19 a non zero data:
        type:<boolean>	-	data: <[]byte{0x0}>
        type:<tinyint>	-	data: <[]byte{0x0}>
        type:<smallint>	-	data: <[]byte{0x0, 0x0}>
        type:<int>	-	data: <[]byte{0x0, 0x0, 0x0, 0x0}>
        type:<bigint>	-	data: <[]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}>
        type:<varint>	-	data: <[]byte{0x0}>
        type:<float>	-	data: <[]byte{0x0, 0x0, 0x0, 0x0}>
        type:<double>	-	data: <[]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}>
        type:<decimal>	-	data: <[]byte{0x0, 0x0, 0x0, 0x0, 0x0}>
        type:<uuid>	-	data: <[]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}>
        type:<timeuuid>	-	data: <[]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}>
        type:<time>	-	data: <[]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}>
        type:<date>	-	data: <[]byte{0x80, 0x0, 0x0, 0x0}>
        type:<duration>	-	data: <[]byte{0x0, 0x0, 0x0}>
        type:<timestamp>	-	data: <[]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}>
        type:<list>	-	data: <[]byte{0x0, 0x0}>
        type:<set>	-	data: <[]byte{0x0, 0x0}>
        type:<map>	-	data: <[]byte{0x0, 0x0}>
        type:<unknown_type_48>	-	data: <[]byte{0xff, 0xff, 0xff, 0xff}>
--- FAIL: TestMarshalZeroValues (0.00s)