bug#58591: Java packages do not appear to keep a reference to their inputs

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hello,

I'm not a Java expert, but this appears to me problematic:

--8<---------------cut here---------------start------------->8---
$ guix build java-commons-dbcp
/gnu/store/jghsa6fmh9vjcsmj7wwilk3w6iblvh32-java-commons-dbcp-2.6.0

$ guix gc -R /gnu/store/jghsa6fmh9vjcsmj7wwilk3w6iblvh32-java-commons-dbcp-2.6.0
/gnu/store/jghsa6fmh9vjcsmj7wwilk3w6iblvh32-java-commons-dbcp-2.6.0
--8<---------------cut here---------------end--------------->8---

Digging a bit more, peeking into the .jar file, which is a ZIP archive:

--8<---------------cut here---------------start------------->8---
$ unzip /gnu/store/jghsa6fmh9vjcsmj7wwilk3w6iblvh32-java-commons-dbcp-2.6.0/\
share/java/java-commons-dbcp.jar -d /tmp/java-commons-dbcp.jar

$ grep -rin CLASSPATH /tmp/java-commons-dbcp.jar
$ grep -rin /gnu/store /tmp/java-commons-dbcp.jar
/tmp/java-commons-dbcp.jar/META-INF/INDEX.LIST:3:/gnu/store/jghsa6fmh9vjcsmj7wwilk3w6iblvh32-java-commons-dbcp-2.6.0/share/java/java-commons-dbcp.jar

$ cat /tmp/java-commons-dbcp.jar/META-INF/INDEX.LIST
JarIndex-Version: 1.0

/gnu/store/jghsa6fmh9vjcsmj7wwilk3w6iblvh32-java-commons-dbcp-2.6.0/share/java/java-commons-dbcp.jar
org
org/apache
org/apache/commons
org/apache/commons/dbcp2
org/apache/commons/dbcp2/cpdsadapter
org/apache/commons/dbcp2/datasources
org/apache/commons/dbcp2/managed
--8<---------------cut here---------------end--------------->8---

Still, no traces of the other libraries such as 'java-commons-pool'
which should be referenced.

I assume this means grafts doesn't currently work for Java libraries.

-- 
Thanks,
Maxim