Unexpected newline before "{" for lambda expression assignments

[schmist]

Since version 0.32.0 lambda expression assignments like:

private fun foo(): () -> Int =
    { 42 }

trigger a Unexpected newline before "{".

For the shown example, there is no need to have a line break after =, but if the first line is getting too long, a line break makes sense.

Is this intended behavior?

[shashachu]

Both the Google and Jetbrains styleguides say no linebreaks before opening curly braces so this is by-design.

https://developer.android.com/kotlin/style-guide#braces
https://kotlinlang.org/docs/reference/coding-conventions.html#formatting

[igorwojda]

I think this should be reopened

If line is to long Android Studio will format below code and move { ... to new line

fun validDateRule(): ValidationRule<LocalDate?> =
        { date: LocalDate?, _: EventType -> ValidationResult(date != null) }

and ktlint complains Unexpected newline before "{"

[shashachu]

In my opinion, for these one-off exceptions, it's better to use a ktlint-disable comment to suppress it rather than complicate the rule. But open to feedback from others.

[igorwojda]

In my project, this violation happens 6 times already.
I think indent before { should be allowed if the previous line ends with = character

(no ktlint violation)
↓
Format code (using Android Studio default settings)
↓

(ktlint violation)

[igorwojda]

We should really prioritize this as this rule contradicts default AS formatting

[pgreze]

+1 I believe @igorwojda example with validDateRule is a good example 👍

[Tapchicoma]

Related - #637