Redmine

I reproduced the problem on the demo.redmine.org:

http://demo.redmine.org/projects/url-sign-test/wiki/Blablabla_cr%C3%A8me_20%?parent=Wiki

I've added a quick-fix to the application_helper.rb (around line 640) which fix the biggest problem for now:

            case options[:wiki_links]
            when :local; "#{page.present? ? Wiki.titleize(page) : ''}.html" + (anchor.present? ? "##{anchor}" : '')
            when :anchor; "##{page.present? ? Wiki.titleize(page) : title}" + (anchor.present? ? "_#{anchor}" : '') # used for single-file wiki export
            else
              wiki_page_id = page.present? ? Wiki.titleize(page) : nil

              # Added manually to quick-fix the following defect: http://www.redmine.org/issues/15885
              wiki_page_id.gsub!('%','%25')

              parent = wiki_page.nil? && obj.is_a?(WikiContent) && obj.page && project == link_project ? obj.page.title : nil
              url_for(:only_path => only_path, :controller => 'wiki', :action => 'show', :project_id => link_project,
               :id => wiki_page_id, :version => nil, :anchor => anchor, :parent => parent)

This (wiki_page_id.gsub!('%','%25')) works only for opening wiki-links containing a percent-sign in the URL:

[[Test 25%]]