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database/sql: storing driver.Value type string into type *time.Time #1574
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I don't think there is any way around this. The Go |
A possible workaround: https://pkg.go.dev/github.com/lib/pq#EnableInfinityTs |
I suppose a toggle is possible to treat -infinity / infinity as the min / max time values. This flag would probably be in I don't plan on implementing it myself, but I think this feature could be merged if someone submitted a PR. |
I'd personally like to have a solution which doesn't rely on having to use |
I looked into this issue today. I abandoned my efforts (as I don't need infinity clamping for now), but one straight forward way to change how infinity values are treated for The code is basically copied and adapted from https://github.com/jackc/pgx/blob/master/pgtype/pgtype.go and https://github.com/jackc/pgx/blob/master/pgtype/builtin_wrappers.go#L398C1-L497C1. A simple working example looked as follows: const (
secondsPerMinute = 60
secondsPerHour = 60 * 60
secondsPerDay = 24 * secondsPerHour
unixToInternal int64 = (1969*365 + 1969/4 - 1969/100 + 1969/400) * secondsPerDay
)
var (
MinTime = time.Unix(0, 0)
MaxTime = time.Unix(1<<63-1-unixToInternal, 999999999)
)
func TryWrapTimeEncodePlan(value interface{}) (plan pgtype.WrappedEncodePlanNextSetter, nextValue interface{}, ok bool) {
switch value := value.(type) {
case time.Time:
return &wrapTimeEncodePlan{}, timeWrapper(value), true
}
return nil, nil, false
}
type wrapTimeEncodePlan struct {
next pgtype.EncodePlan
}
func (plan *wrapTimeEncodePlan) SetNext(next pgtype.EncodePlan) { plan.next = next }
func (plan *wrapTimeEncodePlan) Encode(value any, buf []byte) (newBuf []byte, err error) {
return plan.next.Encode(timeWrapper(value.(time.Time)), buf)
}
func TryWrapTimeScanPlan(target any) (plan pgtype.WrappedScanPlanNextSetter, nextDst any, ok bool) {
switch target := target.(type) {
case *time.Time:
return &wrapTimeScanPlan{}, (*timeWrapper)(target), true
}
return nil, nil, false
}
type wrapTimeScanPlan struct {
next pgtype.ScanPlan
}
func (plan *wrapTimeScanPlan) SetNext(next pgtype.ScanPlan) { plan.next = next }
func (plan *wrapTimeScanPlan) Scan(src []byte, dst any) error {
return plan.next.Scan(src, (*timeWrapper)(dst.(*time.Time)))
}
type timeWrapper time.Time
func (w *timeWrapper) ScanTimestamptz(v pgtype.Timestamptz) error {
if !v.Valid {
return fmt.Errorf("cannot scan NULL into *time.Time")
}
switch v.InfinityModifier {
case pgtype.Finite:
*w = timeWrapper(v.Time)
return nil
case pgtype.Infinity:
*w = timeWrapper(MaxTime)
return nil
case pgtype.NegativeInfinity:
*w = timeWrapper(MinTime)
return nil
default:
return fmt.Errorf("invalid InfinityModifier: %v", v.InfinityModifier)
}
}
func (w timeWrapper) TimestamptzValue() (pgtype.Timestamptz, error) {
infinityModifier := pgtype.Finite
if time.Time(w).Equal(MaxTime) {
infinityModifier = pgtype.Infinity
} else if time.Time(w).Equal(MinTime) {
infinityModifier = pgtype.NegativeInfinity
}
return pgtype.Timestamptz{Time: time.Time(w), InfinityModifier: infinityModifier, Valid: true}, nil
} The above was tested as follows: // ...
config.AfterConnect = func(ctx context.Context, conn *pgx.Conn) error {
tm := conn.TypeMap()
tm.TryWrapEncodePlanFuncs = append([]pgtype.TryWrapEncodePlanFunc{TryWrapTimeEncodePlan}, tm.TryWrapEncodePlanFuncs...)
tm.TryWrapScanPlanFuncs = append([]pgtype.TryWrapScanPlanFunc{TryWrapTimeScanPlan}, tm.TryWrapScanPlanFuncs...)
return nil
}
// ...
var tmin, tmax, tval time.Time
err := pool.
QueryRow(context.Background(), "select '-infinity'::timestamptz, 'infinity'::timestamptz, '2024-01-01T00:00:00Z'::timestamptz").
Scan(&tmin, &tmax, &tval)
// ... |
Describe the bug
database/sql: unsupported Scan, storing driver.Value type string into type *time.Time
To Reproduce
Expected behavior
Return without error.
Actual behavior
Error in rows.Scan: unsupported Scan, storing driver.Value type string into type *time.Time
This is actually a simplify demo when using gorm library and pgx as driver, the default column type in go for timestamp is time.Time, but when the timestamp value set to infinity, the actual driver.Value is string type, hence the scan error happened.
I think this is a problem about how to represent infinity value in time.Time.
For code reference: https://github.com/jackc/pgx/blob/master/pgtype/timestamp.go#L58
Version
c (Debian 10.2.1-6) 10.2.1 20210110, 64-bit
Additional context
Add any other context about the problem here.
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