It’s not easy to know without a bit of context :sm...

# arrow

[pakoito]

It’s not easy to know without a bit of context 😄

[Jose Antonio Jimenez]

https://github.com/aws/aws-lambda-java-libs/blob/master/aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/SNSEvent.java

[Jose Antonio Jimenez]

Trying to flatMap { it.records.toOption() }
.flatMap { it.firstOption() } until i get to the message

[Jose Antonio Jimenez]

that is null

[Jose Antonio Jimenez]

Umm, the issues was:

val message = ObjectMapper().writeValueAsString(null)
Option.fromNullable(message)
Some(null)

[pakoito]

.flatMap { it.firstOption() } if the first record is null it should be Some(null) sadly. Try it.filter { it != null }.firstOption()

[pakoito]

then, fromNullable() seems like a straightforward implementation that cannot fail: https://github.com/arrow-kt/arrow/blob/cde3876ab8e649941f6805ea72fa985a121d6bce/modules/core/arrow-core/src/main/kotlin/arrow/core/Option.kt#L29

[pakoito]

in your casee message is String!, right? After being nullchecked it should become String

[Jose Antonio Jimenez]

Seems, that now is right. Still this behaviour also happens in Scala. This -->

val message = ObjectMapper().writeValueAsString(null)

i obtain Some(null) when

Option(message)

(Scala) or

Option.fromNullable(message)

(Kotlin)

[pakoito]

Wait, how do you check that it’s Some(null), by println the value or with the debugger?

[pakoito]

Because writeValueAsString(null) seems to me like something that’ll return a string "null", which then gets printed as Some(value = "\"null\"") and that may be correct and te corro a gorrazos

[Jose Antonio Jimenez]

With the repl

[Jose Antonio Jimenez]

Yep, you are right 🙁 😞

[pakoito]

hahaahhahaha okay

[pakoito]

well, bug found, crisis averted