How do I make a Task depend on the build.gradle itself?-CodePudding

I have the following build.gradle file. Currently the task generateSources runs every time gradle is executed ("BUILD SUCCESSFUL"). I would instead like it to only execute when the build.gradle file itself changes, so that the build is an incremental build ("UP-TO-DATE")

i.e. I want it's "input" to be the "build.gradle" itself.

How do I do this?

apply plugin: 'java'
apply plugin: 'application'

mainClassName = 'Main'
version = "1.0"

task generateSources() {
    // inputs = ????
    // onlyIf ???
    
    outputs.upToDateWhen { true } // in the real code this is a file
    doFirst {
        println("Hello, World! $project.version")
    }
}

compileJava.dependsOn generateSources

(The code above is simplified to the bare minimum. In reality the task generate some files, and they are configured properly in Task.output)

CodePudding user response：

There are two ways as I know, finalizedBy and dependsOn The finalizedBy means do this after this task

tasks.named("build") { finalizedBy("myTaskName") }

And the dependsOn means that after build do this task

tasks.named("myTaskName") { dependsOn("build") }

More information about tasks on the official docs

CodePudding user response：

It turns out you can just put an input-dependency on the project file object itself with something like inputs.file project.buildFile.

apply plugin: 'java'
apply plugin: 'application'

mainClassName = 'Main'
version = "1.0"

task generateSources() {
    
    inputs.file project.buildFile // only rebuild when _this_ build.gradle changes
    
    outputs.upToDateWhen { true } // in the real code this is a file
    doFirst {
        println("Hello, World! $project.version")
    }
}

compileJava.dependsOn generateSources