is there a way to show inferred types for functions with expression bodies in intellij?

stuff like: fun square(x: int) = x + x

should tell me that the return type is int

I know

oh right, inferred

i guess if you

ctrl+j

on the function, it shows you the inferred return type

Just published an article - "🔥Firebase-ing with Kotlin Coroutines + Flow🌊". Explained about: - Using #kotlin #Coroutines and #Flow with #Firebase Cloud #Firestore. - State management 📱 - Firebase-ing without any listener 😂. Please have a look on this and let me know your valuable feedback! Link: https://medium.com/firebase-developers/firebase-ing-with-the-kotlin-flow-dab1bc364816 #firebase #androiddev #androiddevelopment #android #androiddevelopers #async #androidapp #firebasedev #asyncprogramming #kotlin

https://twitter.com/kotlin/status/1255882186559029248 If you’re using the expression body syntax, try to add explicit return types for any non-trivial functions. This way, the type of the function will not change unexpectedly, which can help prevent surprises. #KotlinTips https://t.co/h19bPYSljE Twitter

Kotlin Kernel for Jupyter Notebook, v0.8 Hi folks! Today we have released a new version of the Kotlin kernel for Jupyter Notebook, and if you are experimenting with data — give notebooks with Kotlin kernel a try. One of the great things about Jupyter Notebook is … Continue reading →

Hi! I was wondering if any of you had already created a behavioral unit test suite for the Spring server? Like performing tests against your APIs? For example, without the admin bearer token results in a rejection etc. Thank you!

Like,

at foo.bar.Task.run(FileName.kt:351)

when the file only has 319 lines.

I've just found this online, slightly modified it to remove the cursing. Running this code will cause a

java.lang.NullPointerException

to be thrown. Shouldn't the compiler recognize that

crash

is modifying the property before it's assigned?

Hi! Does calling

update

on

MessageDigest

like this append or overwrite the data?

val digest = MessageDigest.getInstance("SHA-256")
digest.update("foo".toByteArray())
digest.update("bar".toByteArray())

I see in the source that

update

calls

engineUpdate(input, 0, input.length);

, which:

/**
     * Updates the digest using the specified array of bytes,
     * starting at the specified offset.
     *

This makes me thing that it overwrites the data, but the first snippet seems to work, so I'm confused

Is there a way to supress some types of warnings for whole project instead of specifying them in each file seperately? I want to supress

MemberVisibilityCanBePrivate

and

unused

Im currently doing that by putting this in every file:

@file:Suppress("MemberVisibilityCanBePrivate", "unused")

Is there any way to do this, like we do for experimental apis and opt-ins using gradle compilation args or something.

Is there a way to refer to

kotlin.String

from Java? Trying to set a package-wide Hibernate type mapping default for

String

to PG

text

@TypeDef(name = "string", defaultForType = String::class, typeClass = TextType::class)

The above on a Kotlin class works. The equivalent in

package-info.java

doesn't, presumably because it doesn't think of Kotin strings as Java strings.

https://twitter.com/kotlin/status/1257603544238231555 You can define a function locally (inside another function). When refactoring and extracting an auxiliary function, consider making it local. This can decrease the number of the parameters, as a local function can capture the variables of the surrounding function. #KotlinTips https://t.co/cwOCjTpNYk Twitter

any one have any example for creating custom autocomplete ? As current AutocompleteTextView extended via EditText but i want to extended with List

Let’s say I have this code:

interface ApiMessage<T : ApiMessage<T>> {
  fun convertToBytes(): ByteArray
}

data class GetAllMessagesRequest(): ApiMessage<GetAllMessagesRequest> {
}

And later in my code I want to do something like:

fun performRequest(request: ApiMessage)

But the compiler complain about

One type argument expected for T

How could I achieve something like this and received a generic instance of my interface? I can’t really easily change my

ApiMessage

interface and request message. Thanks!

Hi all. I am writing my first Kotlin production application (Ktor web app) and I need to set everything up. Does anyone have any good up-to-date resources about best tools and libraries to use for things like formatting and linting? Or any other similar things I could use to set everything up like idiomatic Kotlin project?

I want to create a custom annotation to have a nullabillity check like kotlin has. e.g:

// option 1
@SafeGetter // custom annotation
val list: MutableList<String> = emptyList()

// option 2 - custom class 
class SafeMutableList<E> : MutableList<E> {
  @SafeGetter
  override fun get(index: Int) = super.get(index)
}

val list: SafeMutableList<String> = emptyList()

1. compile-time error
if (list.get(7)) { // when running/building this code, it will have a compile-time error

}

2. compile-time safe
list.add("default)
if (list.get(7)) { // this won't compile-time error

}

3. compile-time safe
val index = 7
if (0 <= index && index < list.size) {
   if (list.get(index)) { // this won't compile-time error
   }
}

the reason I wanna create

@SafeGetter

(a placeholder annotation name) is to prevent engineer forgot to handle

IndexOutOfBoundsExceptions or NPE

to reduce runtime error (in our apps) does the above implementation possible? and if yes, is there any reference/tutorial I can read? or maybe slack channel discussion? (if #general is not the right place to ask this kind of topic)

https://twitter.com/kotlin/status/1258418831795593217 The Sequences API is suspiciously similar to the Collections API. This makes it easy to switch from one to the other if necessary. Use the utility functions 'asSequence' and 'toList' to convert between the two. #KotlinTips https://t.co/b0S3Lmp1rD Twitter

I am using io.github.microutilskotlin logging1.7.6 for logging. I am looking for ways to scrub , hide sensitive data in logs.

hello!

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so i want to start writing bots using kotlin, where would be a good place to start?

A good book about kotlin Kotlin In-Depth book provides reader a very clear and simple guide to the basics of Kotlin language. Along with telling the reader about usual moments, there are great "Java vs Kotlin" blocks, showing unobvious details that differ Kotlin not only from Java, but from every C-style languages. Book contains explaining examples, but many of em aren't somehow highlited so it is sometimes difficult to read the code without indents. However, book provide all necessary information for programmer familiar with C-style languages to start coding Kotlin. This book is a very good choice for starting learning Kotlin. Also, it is possible to use it as a handbook to quickly remember some details. Warning: it is only the first part of book, themes like coroutines are consecrated in second part. https://books.google.ru/books/about/Kotlin_In_Depth_Vol_I.html?id=MVDNDwAAQBAJ&redir_esc=y

nah, just y’know, do what most folks do and write a few short kotlin programs to get a handle on the syntax, run through the Koans if you’re feeling confident, reference the docs heavily while you do so

ask questions you’re having a hard time searching for in #getting-started, #codereview when you’ve got larger snippets to review

if you feel like you need a book reference at that point, go for it, but it’s by no means necessary