I’ve known about custom Gradle tasks and functions for a while (Android Studio). I’ve used one, copied from SO and edited to suit my needs, in one of my projects before. This week I got to create a task from scratch to add a dev feature to the app at work. So far so good.

This TIL is not about learning about Gradle tasks. This is about a tiny detail that I didn’t know. I usually write/see tasks written like this

task countChicken {
    // count chicken
    ...
}

When written like this, the chicken are counted immediately every time the Gradle project is synced or built (task configuration).

What I had not known till this week was that anything directly inside that task definition block is executed at the task configuration stage. So, in this case the whole counting of chicken is happening at the task configuration stage, whether we explicitly execute the task or not.

If we only want to execute the task on demand, the task configuration needs to be separated from execution, like so:

task countChicken {
    doLast {
        // count chicken
        ...
    }
}

The doLast ensures that this code block is only executed during task execution. It basically tells Gradle during configuration to run this code block last while executing this task¹. We can also use the doFirst code block to run something first while executing the task. Continue reading →