2018-03-01 18:11 GMT+01:00 Ricardo Wurmus <ricardo.wur...@mdc-berlin.de>:
> Hi Guix, > > we have a problem with jar manifests. When we use the Class-Path > property to ensure that an executable can find its dependencies on the > class path at run-time, we end up with a manifest like this: > > --8<---------------cut here---------------start------------->8--- > Manifest-Version: 1.0 > Class-Path: /gnu/store/i28vi94r8z9f0x02zgkrv87w16ibmqkw-java-htsjdk-2. > 10.1/share/java/htsjdk.jar > Created-By: 1.8.0_151 (Oracle Corporation) > Main-Class: picard.cmdline.PicardCommandLine > --8<---------------cut here---------------end--------------->8--- > > Note that the Class-Path property is broken into two lines. This means > that the reference scanner will miss it and grafting will fail. > > Could we modify the reference scanner to find these lines? Would there be any serious drawback to that? > Breaking up lines longer than 70 characters is according to the manifest > specification, see > https://docs.oracle.com/javase/7/docs/technotes/guides/jar/jar.html > > We cannot just use a wrapper that sets CLASSPATH, because it appears to > be ignored when using a manifest with “Main-Class”. “Main-Class” is > required for executables that can be run like this: > > java -jar whatever.jar > > A possible work-around might be to patch the class loader of our JDKs to > look at a custom Guix-specific file, which we will include in each jar. > That file would be allowed to have longer lines. > > There are two disadvantages: > > 1) we need to patch the JDK > 2) the jars would not do the right thing when executed with a different > JDK (e.g. on a foreign distro). > > What do you think? > > -- > Ricardo > >
