Redmine

      # Keep the category if it's still valid in the new_project

      unless new_project.shared_categories.include?(issue.category)

        issue.category = nil

      end

  # Categories that the issue can be assigned to

  def assignable_categories

    @assignable_categories  ||= (project.shared_categories.open + [IssueCategory.find_by_id(issue_category_id_was)]).compact.uniq.sort

  end

  # Unassigns issues from +category+ if it's no longer shared with issue's project

  def self.update_categories_from_sharing_change(version)

    # Update issues assigned to the version

    update_categories(["#{Issue.table_name}.category_id = ?", category.id])

  end

  # Update issues so their categories are not pointing to a

  # fixed_version that is not shared with the issue's project

  def self.update_categories(conditions=nil)

    # Only need to update issues with a fixed_version from

    # a different project and that is not systemwide shared

    Issue.all(:conditions => merge_conditions("#{Issue.table_name}.category_id IS NOT NULL" +

                                                " AND #{Issue.table_name}.project_id <> #{Version.table_name}.project_id" +

                                                " AND #{IssueCategory.table_name}.sharing <> 'system'",

                                                conditions),

              :include => [:project, :category]

              ).each do |issue|

      next if issue.project.nil? || issue.category.nil?

      unless issue.project.shared_categories.include?(issue.category)

        issue.init_journal(User.current)

        issue.category = nil

        issue.save

      end

    end

  end

  after_update :update_issues_from_sharing_change

  SHARINGS = %w(none descendants hierarchy tree system)

  validates_inclusion_of :sharing, :in => VERSION_SHARINGS

  # Returns the sharings that +user+ can set the category to

  def allowed_sharings(user = User.current)

    SHARINGS.select do |s|

      if sharing == s

        true

      else

        case s

        when 'system'

          # Only admin users can set a systemwide sharing

          user.admin?

        when 'hierarchy', 'tree'

          # Only users allowed to manage versions of the root project can

          # set sharing to hierarchy or tree

          project.nil? || user.allowed_to?(:manage_versions, project.root)

        else

          true

        end

      end

    end

  end

  # Update the issue's fixed versions. Used if a version's sharing changes.

  def update_issues_from_sharing_change

    if sharing_changed?

      if SHARINGS.index(sharing_was).nil? ||

          SHARINGS.index(sharing).nil? ||

          SHARINGS.index(sharing_was) > SHARINGS.index(sharing)

        Issue.update_categories_from_sharing_change self

      end

    end

  end

  # Returns a scope of the Versions used by the project

  def shared_categories

    @shared_categories ||=

      IssueCategory.scoped(:include => :project,

                     :conditions => "#{Project.table_name}.id = #{id}" +

                                    " OR (#{Project.table_name}.status = #{Project::STATUS_ACTIVE} AND (" +

                                          " #{IssueCategory.table_name}.sharing = 'system'" +

                                          " OR (#{Project.table_name}.lft >= #{root.lft} AND #{Project.table_name}.rgt <= #{root.rgt} AND #{Version.table_name}.sharing = 'tree')" +

                                          " OR (#{Project.table_name}.lft < #{lft} AND #{Project.table_name}.rgt > #{rgt} AND #{IssueCategory.table_name}.sharing IN ('hierarchy', 'descendants'))" +

                                          " OR (#{Project.table_name}.lft > #{lft} AND #{Project.table_name}.rgt < #{rgt} AND #{IssueCategory.table_name}.sharing = 'hierarchy')" +

                                          "))")

  end

<p><%= f.select :sharing, @category.allowed_sharings.collect{|c| [format_version_sharing(c), c]} %></p>

<% unless @issue.assignable_categories.empty? %>

<p><%= f.select :category_id, (@issue.assignable_categories.collect {|c| [c.name, c.id]}), :include_blank => true %>

class AddVersionsSharing < ActiveRecord::Migration

  def self.up

    add_column :issue_categories, :sharing, :string, :default => 'none', :null => false

    add_index :issue_categories, :sharing

  end

  def self.down

    remove_column :issue_categories, :sharing

  end

end