Configure Gradle tasks of project to be UP-TO-DATE depending on Git diff result of files / folders provided to this plugin. Circumventing boundaries which maybe cannot be solved at all or only by extensive configuration in Gradle.

Let's say your Gradle project produces a Jar archive using the task provided by the Gradle Java Plugin. But the source files to be compiled and then be packed inside the Jar archive are generated / patched using some external logic (e.g. Ant). A possible configuration looks like this:

// import our so called Blackbox
ant.importBuild("Blackbox.xml") {
    "ant-$it"
}

tasks.named("classes") {
    dependsOn("ant-magic")
}

You know which files or folders are used by this imported Ant target named ant-magic but the Gradle task classes can't set its output to be UP-TO-DATE. Maybe because the input files generated by the Ant target always input the current date/time into the files and therefore the Gradle task classes assumes changes are made everytime even if the input files or folders of the Ant target are static.

An abstract schematic of such a situation can look like the following image:

In the example above, when running the Gradle jar task, everything has to be executed / build again which might work in a single project build but with a big monolith or multi project build this might become expensive over time.

This plugin should provide a simple solution to this problem while only working with the information also available to the user:

• the input files or folders of the blackbox and the hidden processes inside (e.g. Ant targets)
• any task coming later in the graph after "executing" the blackbox

To find out how to apply this plugin to your Gradle project see the information over at the Gradle Plugin Portal!

To use this plugin you only need to apply it and hand over a simple configuration inside the projects gradle.properties file including, as mentioned, a task after the possible blackbox and the necessary input files or folders:

# Necessary property: Map of task by name to necessary files or folders and artifact task
# INFO: All paths must be relative to project directory!
# INFO: Providing the name of an artifact task is optional!
plugins.gitdiffuptodate.config=\
  <task name> : folder, file 1, file 2 : <artifact task name> ;\
  <task name> : file 1, file 2, folder 1, folder 2

# Optional property: When working with tasks of type Jar should the Manifest file be evaluated, defaults to true
# INFO: Will store & evaluate the current Git commit hash using the attribute "Commit-Hash"
plugins.gitdiffuptodate.evaluateManifest=Boolean

# Optional property: When working with tasks of type Jar should the Git commit hashes of the last changes of the
#                    necessary files or folders be evaluated using the Manifest file, defaults to false
# INFO: Will store & evaluate the Hashes, the actual paths are encrypted for security reasons
plugins.gitdiffuptodate.useFileOrFolderHashes=Boolean

See the folders prj-test-groovy and prj-test-kotlin on how to use this plugin with a simple example each.