Defect #36801 (New): Rails Autoload Paths contain plugin libs twice

Due to the way plugins are loaded by Redmine the variable

ActiveSupport::Dependencies.autoload_paths

contains the path to the 'lib' directory of each plugin twice, which should not happen.

When Redmine loads the plugins from config/initializers/30-redmine.rb it calls

Redmine::Plugin.load

Redmine::Plugin.load (defined in lib/redmine/plugin.rb) adds the 'lib' directory of each plugin to

ActiveSupport::Dependencies.autoload_paths

and to

$LOAD_PATH#alias $: 

When each plugin calls

Redmine::Plugin.register

from init.rb (which they ought to do), then in Redmine::Plugin.register all Rails paths in the plugin directory are created by calling

engine_cfg.paths

implicitly by calling

engine_cfg.paths.add'lib',eager_load: true

Then in Redmine::Plugin.register the following call causes the second addition of the autoload_paths

ActiveSupport::Dependencies.autoload_paths+=engine_cfg.eager_load_paths+engine_cfg.autoload_once_paths+engine_cfg.autoload_paths

In some environments this may cause trouble.