Redmine

The problem is in app/models/issue.rb:

def recalculate_attributes_for(issue_id)
if issue_id && p = Issue.find_by_id(issue_id)
      if p.priority_derived?
        # priority = highest priority of open children
        # priority is left unchanged if all children are closed and there's no default priority defined
        if priority_position =
             p.children.open.joins(:priority).maximum("#{IssuePriority.table_name}.position")
          p.priority = IssuePriority.find_by_position(priority_position)
        elsif default_priority = IssuePriority.default
          p.priority = default_priority
        end
      end

      if p.dates_derived?
        # start/due dates = lowest/highest dates of children
        p.start_date = p.children.minimum(:start_date)
        p.due_date = p.children.maximum(:due_date)
        if p.start_date && p.due_date && p.due_date < p.start_date
          p.start_date, p.due_date = p.due_date, p.start_date
        end
      end

      if p.done_ratio_derived?
        # done ratio = average ratio of children weighted with their total estimated hours
        unless Issue.use_status_for_done_ratio? && p.status && p.status.default_done_ratio # <--- !!!!
          children = p.children.to_a
          if children.any?
            child_with_total_estimated_hours = children.select {|c| c.total_estimated_hours.to_f > 0.0}
            if child_with_total_estimated_hours.any?
              average = Rational(
                child_with_total_estimated_hours.sum(&:total_estimated_hours).to_s,
                child_with_total_estimated_hours.count
              )
            else
              average = Rational(1)
            end
            done = children.sum do |c|
              estimated = Rational(c.total_estimated_hours.to_f.to_s)
              estimated = average unless estimated > 0.0
              ratio = c.closed? ? 100 : (c.done_ratio || 0)
              estimated * ratio
            end
            progress = Rational(done, average * children.count)
            p.done_ratio = progress.floor
          end
        end
      end

      # ancestors will be recursively updated
      p.save(:validate => false)
    end
  end

Created a branch: fix-calculating-done-ratio-of-parent-task-from-issue-status.

There are some edge cases to consider when assigning a status to the parent based on the average of the children done ratios when trying to find the closest status for this average:

1. Average of the children done ratios = 0 <==> done_ratio of all children must be 0 or nil. Nil is treated equal to 0. (See (c.done_ratio || 0) below.)
2. There is at least one status.default_done_ratio of nil.
3. Several status.default_done_ratios are equal.

Open questions

1. What if the parent issue does not have the same tracker then the child issues?

Child issues are not relevant since we use only the children average of their done ratio.

1. What if an issue has statuses having the same %-done value assigned?

It is not possible to decide which status is right when at least two status have the same %-done value!