[MSHADE-261] Shade plugin removes module_info.class from the main module

[jira-importer]

Aleksandar Seovic opened MSHADE-261 and commented

I've noticed that maven-shade-plugin 3.1.0 removes all module_info.class files from the shaded artifact. In my opinion, this is wrong.

I understand why it makes sense to remove module_info from the dependencies that are included into the final artifact by the shade plugin, but it should not be removed from the main artifact dependencies are being shaded into.

For example, I just had to repackage gRPC Java by creating a project that merges several gRPC artifacts (grpc-core, grpc-context and grpc-stub) into a single io.grpc Java 9 module in order to address the split package issue (both grpc-core and grpc-context have classes in the io.grpc package, which makes them unusable as Java 9 modules by default).

In the process, I've run jdeps against the original JARs and have created a proper Java 9 module descriptor based on what the original JARs export and require, hoping to create a single JAR that can be used correctly as a Java 9 module, as a temporary workaround until the root issue of split packages is addressed by the gRPC team.

However, I wasn't able to get shade plugin to include my module_info.class into the final artifact, no matter what I tried. In the end, I downgraded to version 3.0.0, which did what I wanted it to do and left my module_info alone.

I can also foresee legitimate scenarios where I would want to shade and relocate some dependency (ASM, for example) inside my module, but that doesn't mean that my module_info should disappear. Nothing changes with regard to my module's encapsulation and requirements just because I've embedded ASM into it, other than the fact that the ASM is no longer an external dependency.

To summarize, while I agree that merging of different module descriptors is not something Maven Shade Plugin should do, and that stripping of module descriptors from the artifacts included by the shade plugin probably makes most sense, I do believe that a hand-written module descriptor in the main artifact should be left alone.

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Affects: 3.1.0

1 votes, 3 watchers

[jira-importer]

Tatu Saloranta commented

I wish I had found this issue sooner, before wasting hours trying to resolve the same issue.

It looks like module-info.class is dropped if:

1. "minimize" enabled (by MinijarFilter)
2. ... but also, even if not, by DefaultShader

and apparently there is no way to opt out. I think it should be possible to turn off this filtering given that it seems possible to produce working module-info.class (esp. by using Moditect plug-in).