Gradle Kotlin allprojects dependencies cause build failure - gradle

Question

In my Gradle project, I can declare a dependencies block with implementation entries, no problem. When I try to declare something like this, however, I get an error:
allprojects {
dependencies {
implementation("...")
}
}
The error I get:
Could not find method implementation() for arguments [org.mockito:mockito-core:2.25.0]
on object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.
I wasn't able to reproduce this with a Java project, so it might have something to do with the Kotlin project. I'm new to Gradle, so I might just be doing something silly? Here's my environment info:
$ gradle --version
------------------------------------------------------------
Gradle 5.2.1
------------------------------------------------------------
Build time: 2019-02-08 19:00:10 UTC
Revision: f02764e074c32ee8851a4e1877dd1fea8ffb7183
Kotlin DSL: 1.1.3
Kotlin: 1.3.20
Groovy: 2.5.4
Ant: Apache Ant(TM) version 1.9.13 compiled on July 10 2018
JVM: 1.8.0_112 (Oracle Corporation 25.112-b15)
OS: Windows 10 10.0 amd64
Minimal reproduction
I can reproduce the issue with a minimal project.
build.gradle:
plugins {
id 'org.jetbrains.kotlin.jvm' version '1.3.21'
}
group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
repositories {
mavenCentral()
}
// This works.
dependencies {
implementation 'org.mockito:mockito-core:2.25.0'
}
// Causes an error. Using a random dependency to reproduce the issue.
allprojects {
dependencies {
implementation 'org.mockito:mockito-core:2.25.0'
}
}
settings.gradle:
rootProject.name = 'demo'
// Removing this line causes the error to go away, but means the module is missing.
include 'submodule'
submodule/build.gradle
// Empty file. I've tried adding various plugins (java / kotlin) to no avail.

Answer 1

The issue in your build.gradle is you are trying to use a build dependency configuration, in this case implementation without specifying the java plugin. The gradle docs says;
The Java plugin adds a number of dependency configurations to your
project, as shown below. Tasks such as compileJava and test then use
one or more of those configurations to get the corresponding files and
use them, for example by placing them on a compilation or runtime
classpath.
One way to fix this is to include java plugin as below (I have tested on 5.2.1 and it worked fine);
allprojects {
apply plugin: 'java'
dependencies {
implementation 'org.mockito:mockito-core:2.25.0'
}
}
The relationship of build configuration to the java plugin has been comprehensively described on
https://docs.gradle.org/current/userguide/java_plugin.html#sec:java_plugin_and_dependency_management
and
https://docs.gradle.org/current/userguide/managing_dependency_configurations.html#managing_dependency_configurations
Also, make sure you don't duplicate this dependency (or any other which is declared in the root or for all projects) in subprojects.