Jars should include directories

[tballard]

Mill builds jars without entries for directories, but directories are cheap and allow searching for resources and are otherwise harmless and thus should be included. (Evidence suggests that maven includes them by default, supporting the claim of being benign)

[lolgab]

Can you provide an example?

[lefou]

Yeah, I created jars with so many build tools and even coded that part multiple times from scratch for various build tools. It could appear as nitpicking to argue for or against additionally explicit directory entries. I nowadays think, it's probably easier to read and probably also easier to process, when these entries are present. And when you told me, that Spring can't find resources properly when directory entries are missing, you had me. It's probably a poor implementation on their side, but nevertheless, it's inconvenient and avoidable.

Only thing I am very opinionated about is, that we keep the META-INF/MANIFEST.MF entry as first and before the META-INF directory entry. This is more in line with the early specs and also makes it much easier to look into jars, e.g. with zless my.jar, which especially helps if you work with OSGi or Manifests in general a lot.

[tballard]

I think the directories may be supposed to precede their contents, too

[lefou]

I think the directories may be supposed to precede their contents, too

Sure. That is also my assumption/understanding. That's why I pointed to the special case with META-INF/.

[lefou]

@tballard Do you mind to give PR #2138 a try?

[tballard]

Yeah I will. I'm writing some code to repack the current one, adding the required directories, so I'll be all practiced up.

[tballard]

Hmm, I thought I was implementing this, although I like your solution better. However, you will note that if you try to add an entry like META-INF/SOMETHING_ELSE you get a collision:
1 targets failed
reds.jar java.util.zip.ZipException: duplicate entry: META-INF/
java.base/java.util.zip.ZipOutputStream.putNextEntry(ZipOutputStream.java:241)

[lefou]

Hmm, I thought I was implementing this, although I like your solution better.

Oh, I though you will start it once you are on holiday, but I didn't realized that this means "now".

However, you will note that if you try to add an entry like META-INF/SOMETHING_ELSE you get a collision: 1 targets failed reds.jar java.util.zip.ZipException: duplicate entry: META-INF/ java.base/java.util.zip.ZipOutputStream.putNextEntry(ZipOutputStream.java:241)

Oh, this is an oversight, as the special case META-INF/ needs to be explicitly added to the seen set. Thanks for testing and pointing this out. I'll push a fix.

[tballard]

Yeah, I had that bug first;-)