Merge upstream changes from ASM 5.2, 6.0-BETA

[retronym]

@forax suggested that the ASM 5.2 would be worthwhile for us as it contains a few bug fixes: http://asm.ow2.org/history.html

ASM 6.0 is almost almost ready too. We might instead jump straight to that, which will give us the platform to read/write module-info.class, although we might not actually need this. It also contains the equivalent of my patch in #12.

Finally, ASM has moved to Git, so we should update (and simplify!) our process for pulling from upstream. We can either merge from the upstream tag, or create a new branch with our changes rebased on the upstream tag.

[lrytz]

I'll do this for 2.12.4

[lrytz]

I created a fork of the new asm git repo here https://github.com/scala/scala-asm (this repo is now renamed).

Not entirely sure yet how to deal with updates. I think having a branch into which we merge changes from upstream is not realistic with the current setup, because

• our fork has the source files moved to a different package / directory
• our fork has removed files that are in the original repo, including some sources files

This would cause many merge conflicts.

Another reason I don't like merging in changes is that it makes it harder to keep track of our own patches. If re-apply our patches on top of their tags each time we upgrade, we can easily see the differences in the git log, and we can also clean up / squash our patches over time.

My current plan: create a new branch each time we start off a new ASM release tag, then re-apply all our changes from the previous branch. Create more scripts to simplify that process.

[lrytz]

I created a branch https://github.com/scala/scala-asm/commits/s-5.1 with all patches from this legacy repo. Pushed a tag in the new repo (https://github.com/scala/scala-asm/releases/tag/v5.1.0-scala-2), which triggered a release. I downloaded the jar from sonatype staging and compared with the one from maven that was released with the legacy repo, they are identical up to a properties file.

[lrytz]

Instructions to upgrade asm in the new repository: https://github.com/scala/scala-asm/blob/readme/README.md

I just did it for 5.2, the process takes ~30 minutes now.

However there seems to be a problem with the artifacts, there are errors when trying to close the repository:

Seems I forgot to upload the public key, will do that.

[lrytz]

OK, added the key, now closing the repository worked (https://oss.sonatype.org/content/repositories/orgscala-lang-1443/). I'll try it out later.

[lrytz]

scala/scala#6084