Cascading: Java tutorial for the Impatient, Part1 : Gradle build fails

Question

When building part1 of the tutorial on CentOS 6.5,java version "1.7.0_51" I get Gradle error:

You can't change configuration 'providedCompile' because it is already resolved!

[localhost part1]$ gradle clean jar

FAILURE: Build failed with an exception.

• Where: Build file '/home/test/wks/Cascading/Java/Impatient/part1/build.gradle' line: 43

• What went wrong: A problem occurred evaluating project ':part1'.

  You can't change configuration 'providedCompile' because it is already resolved!

• Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

What may be wrong? Thanks!

Answer 1

This is a shot in the dark but I had the same issue (different project) and searching is how I landed here on SO. In my case the error was caused by a '+=' in my script that was adding a single element to a collection. The other response to the OP's issue from another forum is simply to use Gradle 1.12.

HTH.

This answer has a wider scope than the "tutorial" build, and also applicable to those who land here while searching for a solution to the actual error reported by the build.

From Gradle Community Forums:

Gradle 2 updated to Groovy 2.3, which no longer supports the use of += for adding a single element to a collection. So instead of scopes.PROVIDED.plus += configurations.provided it's now scopes.PROVIDED.plus += [configurations.provided]. (The other uses of '+=' are OK.)

Answer 2

AS JavaBrewer proposed, if you compile this against a version of gradle bigger than 2.0 you need to change the file: common/providedCompile.gradle

apply plugin: 'maven'

configurations {
  providedCompile
}

sourceSets {
  main.compileClasspath += [configurations.providedCompile]
}

task mappings {
  conf2ScopeMappings.addMapping( 0, configurations.providedCompile, Conf2ScopeMappingContainer.PROVIDED )
}

idea {
  module {
    scopes.PROVIDED.plus += [configurations.providedCompile]
  }
}

javadoc {
  classpath += configurations.providedCompile
}

eclipse {
    classpath{
        plusConfigurations += [configurations.providedCompile]
    }
}

Pay attention that since version 2.0 in order to add an element to a collection with the operator +=, you have to append another collection. you achieve this by adding []