gradle: Implicit dependencies between tasks

Question

I have the following Gradle (kotlin-dsl) project layout

tools-root
    |- tools-ui     // reactjs
    |- tools-main   // springboot

It is required to copy the tool-ui/build directory to the tools-main/build/resources/main/static directory, before the tools-main springboot jar is created. The belows tasks and dependencies are created to achieve this in tools-main/build.gradle.kts

// Copy WebUI build to SpringBoot Jar
val copyWebUi = tasks.register<Copy>("copyWebUi") {
   
    dependsOn(tasks.getByPath(":tools-ui:build"))

    from(project(":tools-ui").layout.buildDirectory)
    into(layout.buildDirectory.dir("resources/main/static/simconfig"))
}

tasks.getByName<BootJar>("bootJar") {
    dependsOn(copyWebUi)
}

However it gives the below warnings during build.

> Task :tools-main:copyWebUi
Execution optimizations have been disabled for task ':tools-main:copyWebUi' to ensure correctness due to the following reasons:
  - Gradle detected a problem with the following location: 'C:\tools-root\tools-main\build\resources\main\static\simconfig'. 
    Reason: Task ':tools-main:bootJarMainClassName' uses this output of task ':tools-main:copyWebUi' without declaring an explicit or implicit dependency. 
    This can lead to incorrect results being produced, depending on what order the tasks are executed. 
    Please refer to https://docs.gradle.org/7.3.3/userguide/validation_problems.html#implicit_dependency for more details about this problem.

> Task :tools-main:bootJar
> Task :tools-main:inspectClassesForKotlinIC

> Task :tools-main:jar
Execution optimizations have been disabled for task ':tools-main:jar' to ensure correctness due to the following reasons:
  - Gradle detected a problem with the following location: 'C:\tools-root\tools-main\build\resources\main'. 
    Reason: Task ':tools-main:jar' uses this output of task ':tools-main:copyWebUi' without declaring an explicit or implicit dependency. 
    This can lead to incorrect results being produced, depending on what order the tasks are executed. 
    Please refer to https://docs.gradle.org/7.3.3/userguide/validation_problems.html#implicit_dependency for more details about this problem.

How to resolve this error?
I am not sure I have understood anything from the link provided in the error message.

Answer 1

I found an alternate way to resolve this error using the Springboot gradle plugin's BootJar task.

// Copy WebUI build to SpringBoot Jar
tasks.getByName<BootJar>("bootJar") {
    dependsOn(":tools-ui:build")
    from(project(":tools-ui").buildDir) {
        into("BOOT-INF/classes/static/")
    }
}

This task configuration will directly copy the UI build files to the springboot application jar. And this doesn't emit the "implicit dependencies" warning.