Hi, I have a question about how to order the execution of tasks in a multi-module project. I know, normally gradle does verify which sub-projects and tasks depend on each other and normally this does work quite well, but our build in our build-pipeline has the same error described in https://github.com/gradle/gradle/issues/27576 which prevents us from building the project. The exact error we get is

org.gradle.internal.execution.WorkValidationException: A problem was found with the configuration of task ':yedi-domain:kaptKotlin' (type 'KaptWithoutKotlincTask').
  - Gradle detected a problem with the following location: '/data/home/agent-02/agent/work/7bfe31a37ea5b299/idoc-model/build/libs/idoc-model-5.24.40.1-RC-gradle-fix-1.jar'.
    
    Reason: Task ':domain:kaptKotlin' uses this output of task ':idoc-model:sourcesJar' without declaring an explicit or implicit dependency. This can lead to incorrect results being produced, depending on what order the tasks are executed.
    
    Possible solutions:
      1. Declare task ':idoc-model:sourcesJar' as an input of ':domain:kaptKotlin'.
      2. Declare an explicit dependency on ':idoc-model:sourcesJar' from ':domain:kaptKotlin' using Task#dependsOn.
      3. Declare an explicit dependency on ':idoc-model:sourcesJar' from ':domain:kaptKotlin' using Task#mustRunAfter.
    
    For more information, please refer to <https://docs.gradle.org/8.4/userguide/validation_problems.html#implicit_dependency> in the Gradle documentation.

What can I do to insure that the module

idoc-model

, especially the tasks sourcesJar, run before

domain:kaptKotlin

? We tried something like

afterEvaluate {
    tasks.named("kaptKotlin") {
        dependsOn(":idoc-model:sourcesJar")
   }
}

in the domain

build.gradle

file, which worked sometimes on the build pipeline but did not work locally under special circumstances (starting Spring Boot in IntelliJ). To make it work locally again we had to change the depending task from

:idoc-model:sourcesJar

to

:idoc-model:build

Any thoughts on how to tackle this problem?

Generally, any solution based on

dependOn

and related ones are patches. The real issue is those tasks are not setting the input/outputs correctly.

Thanks for the info! May I ask, what it means that the task does not set the input/outputs correctly? what is an expected output of a task in this situation?

I think the real problem is the other part:

it is not good that one project depends on the task from another project

thats more or less the whole configuration:

// idoc-model build.gradle
plugins {
    id 'org.unbroken-dome.xjc'
}

xjc {
    srcDirName = 'resources'
}


task sourcesJar(type: Jar) {
    duplicatesStrategy = 'include'
}

and

// domain build.gradle
dependencies {
    implementation project(':idoc-model')
    implementation "com.querydsl:querydsl-jpa"
    kapt "com.querydsl:querydsl-apt:jpa
    // ...
}

afterEvaluate {
    tasks.named("kaptKotlin") {
        dependsOn(":idoc-model:sourcesJar")
   }
}

I don't know what that plugin is, but when a plugin generates code like Java classes, it is generated in the same module, and the other module depends on the module in which the code has been generated. Generating code inside a different module is done by default or is a setup you are doing?

the code is generated by

xjc

and the task

:xjcGenerate

which is part of

gradle build

but those classes are generated in the same module, or in the folders of the second module

sorry for the late reply, they are getting generated in the

:idoc-model

module and the

:domain

module uses them

Some notes: • any explicit

dependsOn

where on the left-hand side is not a lifecycle task is a code smell and as Javi said more a sign that task outputs are not wired properly to task inputs, the possible solutions in that message are actually all just duct-tape and not a proper solution in practically all cases •

afterEvaluate

is highly discouraged. The main gain you get from using it are timing problems, ordering problems, and race conditions. It is like using

SwingUtilities.invokeLater

or

Platform.runLater

to "fix" a GUI problem. It just does symptom treatment, delaying the problem to a later, harder to reproduce, harder to debug, and harder to fix point in time. • One of the most usual cases for this error are overlapping or wrongly declared outputs, so for example task

A

and task

B

both have directory

X

as output directory and write a file into it, then task

C

depends on outputs of

A

and you get that error message for

B

and

C

as due to the overlapping outputs the files in

X

are considered output for both,

A

and

B

wrongly. • The other most usual case for this error is, if you actually do not wire task outputs to task inputs properly, or do not properly and safely share things between projects, but configure paths manually and thus missing task dependencies. • What makes me 🤔 is,

idoc-model-5.24.40.1-RC-gradle-fix-1.jar

does not look to me like something a task called

sourcesJar

should produce, because a

sourcesJar

typically generates a file ending with

-sources.jar

, so maybe indeed somehow the outputs of your

sourcesJar

task are wrong. • But as Javi said, it is hard to give concrete advice without seeing the project or at least an MCVE