Groovy 梯度任务执行

下面的gradle构建脚本

task hello << {
            println "task hello"
}

hello << {
   println "th"
}

但一个人的订单反转导致了错误：

* What went wrong:
A problem occurred evaluating root project 
> Could not find property 'hello' on root project

---

这个错误是怎么回事？你能用Groovy的观点解释一下吗？

代码可以用Java伪代码进行如下翻译：

Task task = project.addTask("hello");
task.doLast(() -> println("hello"));

task = project.getTaskByName("hello"); // works fine, because a task "hello" has bee added before
task.doLast(() -> println("th"));

如果你切换这两个操作，你会得到

Task task = project.getTaskByName("hello"); // doesn't work, because no task "hello" has been defined before
task.doLast(() -> println("th"));

task = project.addTask("hello");
task.doLast(() -> println("hello"));

---

很明显，由于您试图修改一个尚未定义的任务，这是行不通的。

当然，如果您只是简单地交换这些代码段，那么第一个任务中就不会有“

任务”

”。

Task task = project.getTaskByName("hello"); // doesn't work, because no task "hello" has been defined before
task.doLast(() -> println("th"));

task = project.addTask("hello");
task.doLast(() -> println("hello"));