The following XML should create a repro:
In an atlassian-plugin.xml which does NOT have a <component-import/> tag for PermissionService. Furthermore, even explicitly component-import-ing the condition class doesn't resolve it. If the condition class depended upon several beans, you'd have to trial-and-error determine each of its transitive dependencies and add them one-by-one.
A complete example of the bugged condition can be found here: https://github.com/palantir/stashbot/blob/7226bedc0ea5e886787a46a4b31125bdda418598/src/main/resources/atlassian-plugin.xml
In this revision of the file, I tried adding component-imports fort he condition classes but it just caused things to fail silently (and frustratingly), in stash 2.6.1 the plugin fails to enable.