big bug: Not Sortable

[ABOB9]

var count int64 func Ulid() string { return ulid.MustNew(ulid.Timestamp(time.Now()), ulid.Monotonic(rand.New(rand.NewSource(atomic.AddInt64(&count, 1))), 0)).String() }

for that,I write some testing code:

now := time.Now() id := ulid.MustNew(ulid.Timestamp(now), ulid.Monotonic(rand.New(rand.NewSource(1)), 0)) id2 := ulid.MustNew(ulid.Timestamp(now), ulid.Monotonic(rand.New(rand.NewSource(2)), 0)) fmt.Println( (id2.String() > id.String()) == true) // false if (id2.String() > id.String()) == false { t.Error("big bug") } I want to get a true, but it return a false to me.

but the following code give me a true: now := time.Now() id := ulid.MustNew(ulid.Timestamp(now), ulid.Monotonic(rand.New(rand.NewSource(99)), 0)) id2 := ulid.MustNew(ulid.Timestamp(now), ulid.Monotonic(rand.New(rand.NewSource(100)), 0)) fmt.Println( (id2.String() > id.String()) == true) // true if (id2.String() > id.String()) == false { t.Error("big bug") }

[tsenart]

You get true because you're using the same timestamp to generate the two ULIDs, so the only difference between them two is the random part. If you want id2 to sort after id1 even if they have the same time component, then you need to use the same Monotonic source.

Check this example: https://go.dev/play/p/ZsxbUBqef_6

[ABOB9]

Thank you very very much!