DuplicatesStrategy.FAIL doesn't work with transform

[boris-petrov]

I have something along the lines of:

task foo(type: ShadowJar, dependsOn: fooClasses) {
	from sourceSets.foo.output

	configurations = [project.configurations.fooRuntimeClasspath]

	archiveBaseName = 'foo'
	zip64 = true

	mergeServiceFiles()
	mergeGroovyExtensionModules()
	transform(AppendingTransformer) {
		resource = 'META-INF/extensions.idx'
	}

	duplicatesStrategy = DuplicatesStrategy.FAIL
}

There are multiple META-INF/extensions.idx files which, when duplicatesStrategy is NOT DuplicatesStrategy.FAIL, get merged correctly but when it IS DuplicatesStrategy.FAIL - it blows up with org.gradle.api.file.DuplicateFileCopyingException: Encountered duplicate path "META-INF/extensions.idx" during copy operation configured with DuplicatesStrategy.FAIL. Am I doing something wrong or is this a bug? I think that having specified that I want those files appended means that it should not blow up with that error, right?

[Gamebuster19901]

I'm having the opposite problem. When I set duplicatesStrategy = DuplicatesStrategy.INCLUDE, duplicates are not included in the shadowed jar.

[Goooler]

It's the correct behavior from Gradle side.

Throw a DuplicateFileCopyingException when subsequent items are to be created at the same path.
Use this strategy when duplicates are an error condition that should cause the build to fail.

https://docs.gradle.org/current/javadoc/org/gradle/api/file/DuplicatesStrategy.html#FAIL

[boris-petrov]

@Goooler thanks for the response. I understand what DuplicatesStrategy.FAIL means but in this case it's not so straight-forward. After all, I've specified a transformer that appends files with the same name. Similar with mergeServiceFiles - does it make sense to have mergeServiceFiles and DuplicatesStrategy.FAIL and that to blow up when there are multiple service-files? Well, no, as I've explicitly requested they to be merged. Same with an AppendingTransformer - I want all META-INF/extensions.idx files to be appended - why would it blow up when there's more than one?

[Goooler]

You are right, I can repro this in #1233.