As a follow-up to https://github.com/jenkinsci/custom-war-packager/pull/51 , we could introduce even more effective caching of Plugin/non-plugin lists in Custom War Packager.

One of the ways would be to introduce an UpdateCenter-based caching:

• When the build starts, CWP downloads JSON plugin file from a Jenkins update center specified for the build in CWP
• UC authentication credentials may be passed as optional parameters (YAGNI?)
• CWP builds the cache based on the downloaded plugin list. Artifact IDs from the list are considered as plugins, others are skipped
• There is a way to define additional inclusions using an optional configuration parameter

Cons:

• Blacklisted plugins won't appear in the updates list => the plugins may be considered as JARs without notice
• Non-released plugins (alpha/beta/incrementals before 1.0) also won't appear by default (in the default update center), inclusions will be required