Entity created with default timestamp is null

[fabianloewe]

I have the following table:

object MyTable : LongIdTable() {
    // ...
    val created = timestamp("created").defaultExpression(CurrentTimestamp).databaseGenerated()
    val modified = timestamp("modified").defaultExpression(CurrentTimestamp).databaseGenerated()
    // ...
}

and the following entity:

class MyEntity(id: EntityID<Long>) : LongEntity(id) {
    companion object : LongEntityClass<MyEntity>(MyTable)

    // ...
    val created by MyTable.created
    var modified by MyTable.modified
    // ...
}

Now, if I create the entity with:

val obj = MyEntity.new {
    // All properties are initialized except created and modified
}

// Fails
assertNotNull(obj.created)

But in the IDEA debugger, if I click on the property, it shows the Instant object that has been created in the database.
If I run into the assertion after clicking the property, the assertion doesn't fail anymore.
How is that possible?

[constructivetim]

Can confirm that this breaking change was introduced in 0.57. everything works as it should in 0.56. I believe the title of the bug report should be

"Timestamps are no longer defaulting since 0.57"

[constructivetim]

to be fair, this breaking issue is documented here: https://www.jetbrains.com/help/exposed/breaking-changes.html#0-57-0

[itulau]

Is there another way to recreate this behavior similar to defaultExpression on insert?

to be fair, this breaking issue is documented here: https://www.jetbrains.com/help/exposed/breaking-changes.html#0-57-0

[obabichevjb]

@fabianloewe Hi, thank you for submitting the issues.

If I run into the assertion after clicking the property, the assertion doesn't fail anymore.
How is that possible?

Answering the question, How is that possible, I expect that it's concurrency problem, and Exposed sends the data to the database while you're on the breakpoint, updates the cache and you get the value from the DB.

But you don't get it without breakpoint, because DAO has issue now (probably for a long time), it doesn't flush the data if you try to read the value that has default value on the database side.

Normally, DAO should understand that you try to read the value, that is not in cache yet and flush data, but it doesn't do that. As I can see it's the original issues.

As a workaround right now, you can flush the data before reading that default value. But in general it's of course not a solution, because it would be annoying to have fear to get values from entities, and flush them every time.