Add skipLocalJars=true option to completely skip the transformation of locally-produced Jars

[jjohannes]

The purpose of this plugin is to transform published Jars. Local Jars do not need to be modified. By default, Artifact Transforms also transform locally created artifacts. I am not sure if this was the case when this plugin was initially created (Gradle 6.x). It feels like this was added to Gradle at a later point (not sure).

So far, the plugin only does something for the consuming projects. This would avoid issues like:

• Configuration options to (de)activate the plugin for selected Configurations and Source Sets #134 (comment)
• Give a better error message than 'Transform output ... must exist' #106

I am not sure though if there is an API for this by now. Setting the attribute (e.g. on runtimeElements and apiElements) should not:

• Influence which attributes are published
• Influence the variant selection step (only the artifact selection/transformation step)

[jjohannes]

For reference, see this comment:

extra-java-module-info/src/main/java/org/gradlex/javamodule/moduleinfo/ExtraJavaModuleInfoTransform.java

Lines 221 to 226 in acfd46e

	// If the jar does not exist, we assume that the file, which is produced later is a local artifact and a module.
	// For local files this behavior is ok, because this transform is targeting published artifacts.
	// Still, this can cause an error: https://github.com/gradle/gradle/issues/27372
	// See also:
	// - https://github.com/gradlex-org/extra-java-module-info/issues/15
	// - https://github.com/gradlex-org/extra-java-module-info/issues/78

[tg-freigmbh]

The purpose of this plugin is to transform published Jars. Local Jars do not need to be modified

I am not quite sure if I understand this correctly. We do need the feature to modify unpublished artifacts quite a lot.

The use case is that a lot of our code relies on legacy xmlbeans which generates a local jar which does not contain a module-info.
But you can use it in combination with jpms just fine, as you can use the the autogenerated modulename from the filename. This works fine until gradle comes into play that unfortunatelly turns a blind eye to this functionality.
So while I agree that the error messages can be sometimes very strange and misleading, I have to state that there really is a usecase for modifying local jars

[jjohannes]

Thanks for sharing the use case @tg-freigmbh. Will make sure not to break it.

If we add this at all, it should be an opt-in configuration option and the error message (#106) then can suggest you to turn on the option.

[jjohannes]

In 1.11 there will be a new opt-in for this for users who face issue because they need to resolve during configuration time (for whatever reason) – skipLocalJars = true (#165).