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Alex Martian
Alex Martian

Reputation: 3782

gradle dependencies: what "classpath" keyword means exactly and where it is documented?

I've did web search for "gradle classpath site:stackoverflow.com" and "gradle classpath" and found relevant info in only:
Gradle: What is the difference between classpath and compile dependencies?

In the answer by Teng-pao Yu it is written:

compile 'org.hibernate:hibernate-core:5.0.5.Final' is a module dependency declaration. The compile configuration (which is now deprecated by the implementation configuration.) is merely a keyword for Implementation only dependencies. It is not a keyword describing which type of dependency it is (by type here I'm following the three types defined in the tutorial, i.e. module, file, and project.)

So as I understood classpath is also keyword. I've tried to find its` meaning in gradle docs: https://docs.gradle.org/current/userguide/declaring_dependencies.html

And some others referenced in it:
https://docs.gradle.org/current/userguide/dependency_management_for_java_projects.html https://docs.gradle.org/current/userguide/java_library_plugin.html https://docs.gradle.org/current/dsl/org.gradle.api.artifacts.Configuration.html https://docs.gradle.org/current/userguide/variant_model.html https://docs.gradle.org/current/userguide/java_plugin.html

Also: https://docs.gradle.org/current/javadoc/org/gradle/api/initialization/dsl/ScriptHandler.html https://docs.gradle.org/current/javadoc/org/gradle/api/tasks/Classpath.html https://docs.gradle.org/current/userguide/organizing_gradle_projects.html

There are mentions of 'compileClasspath'. If classpath keyword is merely deprecated as compile one, why is it absent from docs?

P.S. I mean like in:

buildscript {
    repositories {
        jcenter()
        maven {
            url 'https://maven.google.com/'
            name 'Google'
        }
        google()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.4.1'
   }
}

ADDED after answer:

search for getBuildscript() in gradle source code: search for getBuildscript() in gradle source code

Upvotes: 1

Views: 6289

Answers (1)

Cisco
Cisco

Reputation: 22952

So as I understood classpath is also keyword

This is incorrect. classpath, compile, implementation, api, and many more are all configurations. Configurations in Gradle are tree-like meaning typically each one extends from some parent:

configuration tree

Source: https://docs.gradle.org/current/userguide/java_library_plugin.html#sec:java_library_configurations_graph

For example, using the implementation configuration, when you do the following in your build.gradle:

dependencies {
    implementation("org.apache.commons:commons-lang3:3.9")
}

You are actually doing:

project.getDependencies().add("implementation", "org.apache.commons:commons-lang3:3.9")

The former uses the Gradle DSL while the latter uses the Gradle API directly.

If classpath keyword is merely deprecated as compile one, why is it absent from docs?

The compile configuration is deprecated as noted here. The classpath configuration is still used, but typically only used with the buildscrpt { } block.

So for your example:

buildscript {
    dependencies {
        classpath("com.android.tools.build:gradle:3.4.1")
    }
}

Desugars to:

project.getBuildscript().getDependencies().add("classpath", "com.android.tools.build:gradle:3.4.1")

Upvotes: 10

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