[FOP-2733] [PATCH] Drop dependency on Avalon-Framework

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.4
• Flags: Patch
• Assignee: Simon Steiner
• Reporter: Chris West
• Created: 21/Aug/17 10:13
• Updated: 15/Apr/20 09:17
• Resolved: 22/Jan/19 11:54

Description

FOP depends on avalon-framework, an old Apache project officially abandoned in 2004. Nearly nobody uses avalon-framework anymore, and I'd like to see it laid to rest.

avalon-framework no-longer compiles with Java 9. Fixing it yet again seems like insanity. This isn't a problem for Maven users, who can keep using the old binary (and suffer slow verification on startup), but is a problem for distros like Debian, who want to be able to build everything.

Others have asked about this before, e.g. http://apache-fop.1065347.n5.nabble.com/FOP-and-Avalon-td44302.html

I propose removing the dependency on Avalon entirely, fixing the couple of cases where it breaks, and inlining the two packages that are actually still used.. I have created a patch here: https://github.com/apache/fop/compare/trunk...FauxFaux:trunk , also attached.

It's not great to read in patch form, so here's a summary of the changes:

• Remove dependence on avalon-framework from Maven, classpath variables etc.
• Add Avalon's configuration package as main:org.apache.fop.configuration directly, and keep using it essentially unmodified.
• Add Avalon's logging framework as test:org.apache.fop.threading.logger. This is only used in test code, in the threaded test code runner. It is essentially source compatible with log4j/commons-logging, so could probably be deleted.
• Change `CIDFontType` from a Avalon enum to a Java5 `enum`. This appears to be source, but not binary, compatible.
• Remove some use of lifecycle management interfaces in test code, which are not doing anything.
• Change some exception printing in test code to print the full exception (using the Java api), instead of a truncated exception. The output is not asserted upon, just sent to stderr.
• Stop using Cascading*Exception in tests, and for ConfigurationException. I doubt anyone will notice, as it offers no real functionality.

That's it!

The most controversial thing here is probably adding the configuration package, and the extra lines of code it drags along with it. I am happy to give it a bit of a polish; make significant changes to fop to remove all the unused interfaces / abstract classes (which are just waste); put some generics and formatting in, etc.?

Issue Links

• links to: GitHub Pull Request #43