Replace File in Gradle Build

Question

I am trying to replace a file in my resource folder (src/main/resources) with a new file generated by the Gradle build script. I'm having trouble doing this; the exclusion seems to be remembered, and preventing the addition of my new file.

Here's a short example that illustrates the behavior.

Project Structure:

TestProject
-- src/main/java
---- entry
------ EntryPoint.java
---- run
------ HelloWorldTest.java
-- src/main/resources
---- test.properties // FILE TO REPLACE

test.properties contents in src/main/resources:

Wrong File with extra text to make it obvious which one is being put into the jar based on size

build.gradle:

apply plugin: 'java'

task makeProp {
    def propDir = new File(buildDir, "props")
    ext.propFile = new File(propDir, "test.properties")
    outputs.file propFile

    doLast {
        propDir.mkdirs()
        propFile.createNewFile()
        propFile.withWriter('utf-8') { writer ->
            writer.writeLine 'Right File'
        }
    }
}

jar {
    dependsOn('makeProp')

    if (project.hasProperty('testExclude')) {
        sourceSets {
            exclude('test.properties')
        }
    }

    from (makeProp.propFile) {
        into '/'
    }
}

JAR contents of ./gradlew build (both files included):

Archive:  TestProject.jar
  Length     Date   Time    Name
 --------    ----   ----    ----
        0  08-07-15 14:27   META-INF/
       25  08-07-15 14:27   META-INF/MANIFEST.MF
        0  08-07-15 13:50   run/
      499  08-07-15 13:50   run/HelloWorldTest.class
        0  08-07-15 13:50   entry/
     1413  08-07-15 13:50   entry/EntryPoint.class
       95  08-07-15 14:27   test.properties
       11  08-07-15 14:03   test.properties
 --------                   -------
     2043                   8 files

JAR contents of ./gradlew build -PtestExclude (neither file included):

Archive:  TestProject.jar
  Length     Date   Time    Name
 --------    ----   ----    ----
        0  08-07-15 14:29   META-INF/
       25  08-07-15 14:29   META-INF/MANIFEST.MF
        0  08-07-15 13:50   run/
      499  08-07-15 13:50   run/HelloWorldTest.class
        0  08-07-15 13:50   entry/
     1413  08-07-15 13:50   entry/EntryPoint.class
 --------                   -------
     1937                   6 files

Answer 1

I have done something very similar and this is what worked for me. The main objective is to make sure the task runs before your jar is created and your files are processed. Try this out.

    // create a properties file add it to folder preprocessing
    task propertiesFile << {
        // 
        description 'Dynamically creates a properties file.'

        // needed for the first pass
        def folder = project.file('src/main/resources');
        if(!folder.exists()){
            folder.mkdirs()
        }

        //write it to a propertiess file
        def props = project.file('src/main/resources/test.properties')
        props.delete()
        props << 'write this to my file!!!!'

    }

    processResources.dependsOn propertiesFile