Sibling project seems not using it's dependency's build.gradle script - gradle

Question

I have multi-module project with a structure like this:
|fullstack
\backend
|build.gradle
\frontend
|build.gradle
|build.gradle
|settings.gradle
Settings.gradle:
rootProject.name = 'fullstack'
include 'backend'
include 'frontend'
backend depends on ktor, so it's build.gradle contains repository:
maven { url "https://dl.bintray.com/kotlin/ktor" }
And backend module builds well.
Then I want to share some common classes between backend and frontend. I could make third module api and make others depend on it. But now I want to avoid third module and just make frontend to depend on backend.
I added the dependency to the frontend's gradle.build:
compile project (':backend')
and tried to build the whole project, but got an error:
Could not resolve all files for configuration
':frontend:compileClasspath'.
Could not find io.ktor:ktor-server-netty:0.9.1. Searched in the following locations:
https://repo.maven.apache.org/maven2/io/ktor/ktor-server-netty/0.9.1/ktor-server-netty-0.9.1.pom
https://repo.maven.apache.org/maven2/io/ktor/ktor-server-netty/0.9.1/ktor-server-netty-0.9.1.jar
Required by:
project :frontend > project :backend
It obviously didn't scan repositories of backend module. Why?
UPDATE
I've added repositories as said in answers. But when I try to import in frontend/main.kt any class from backend I get:
:frontend:compileKotlin2Jse: D:\...\frontend\src\main\kotlin\main.kt: (1, 8): Unresolved reference: com
e: D:\...\frontend\src\main\kotlin\main.kt: (2, 8): Unresolved reference: com
How to make it visible for frontend?
Root build.gradle:
group 'com.norg.parts'
version '1.0-SNAPSHOT'
buildscript {
ext.kotlin_ver = '1.2.50'
repositories {
mavenCentral()
}
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_ver"
}
}
allprojects {
project.ext {
kotlin_version = kotlin_ver
ktor_version = '0.9.1'
}
repositories {
jcenter()
mavenCentral()
maven { url 'https://dl.bintray.com/kotlin/ktor' }
maven { url 'https://dl.bintray.com/kotlin/kotlinx' }
maven { url 'https://mvnrepository.com/artifac/' }
maven { url "https://dl.bintray.com/kotlin/exposed" }
}
}
apply plugin: 'java'
apply plugin: 'kotlin'
sourceCompatibility = 1.8
dependencies {
compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
testCompile group: 'junit', name: 'junit', version: '4.12'
}
compileKotlin {
kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
kotlinOptions.jvmTarget = "1.8"
}
jar {
manifest {
attributes 'Main-Class': 'com.norg.parts.MainKt'
}
//TODO include jar from frontend!
}

Answer 1

The problem is that there can be 2 dependencies / repositories blocks. The first one is in the buildscript which looks like this:
buildscript {
repositories {
jcenter()
mavenCentral()
maven { url "https://dl.bintray.com/kotlin/ktor" }
}
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
}
}
This is responsible for setting up tooling and plugins. Then when you set up the config of your project itself you can do several things. If you don't have a multi-module project you just dump it into your build.gradle then the file looks like this:
buildscript {
repositories {
jcenter()
mavenCentral()
maven { url "https://dl.bintray.com/kotlin/ktor" }
}
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
}
}
repositories {
jcenter()
mavenCentral()
maven { url "https://dl.bintray.com/kotlin/ktor" }
}
dependencies {
compile "io.ktor:ktor-server-core:$ktor_version"
}
In your case you should use either allprojects which means that all configuration which you put in that block will be applied to all your projects (including root), or subprojects. In the latter case, the block will be applied to only your subprojects (root not included). This looks like this:
buildscript {
repositories {
jcenter()
mavenCentral()
maven { url "https://dl.bintray.com/kotlin/ktor" }
}
dependencies {
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
}
}
subprojects {
repositories {
jcenter()
mavenCentral()
maven { url "https://dl.bintray.com/kotlin/ktor" }
}
dependencies {
compile "io.ktor:ktor-server-core:$ktor_version"
}
}
Your problem is that you did not add the repository itself to your project config, only your buildscript config.
If you are planning to mix frontend and backend code you can now use Kotlin Multiplatform Projects. I've written about this here.
Response to your edit:
You really need to move all this to a subprojects block:
subprojects {
apply plugin: 'java'
apply plugin: 'kotlin'
sourceCompatibility = 1.8
dependencies {
compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
testCompile group: 'junit', name: 'junit', version: '4.12'
}
compileKotlin {
kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
kotlinOptions.jvmTarget = "1.8"
}
jar {
manifest {
attributes 'Main-Class': 'com.norg.parts.MainKt'
}
//TODO include jar from frontend!
}
}
and you also need to add the backend project as a dependency to your frontend project in that project's build.gradle. I'd strongly advise you to read the Gradle Documentation since this is a Gradle issue not a Kotlin issue whatsoever.

Answer 2

Dependencies are transitive, but repositories are not. This is why most projects have a allprojects block in the root build file defining the repositories for all subprojects at the same time.