[api] avoid conflicting flags in projects

Do not copy a flag if it has been set with same specification level.
No matter if it is an enable or disable one.

src/api/app/models/flag.rb

@@ -4,6 +4,13 @@ class Flag < ActiveRecord::Base
 
   belongs_to :architecture
 
+  validate :validate_duplicates, :on => :create
+  def validate_duplicates
+    if Flag.where("status = ? AND repo = ? AND project_id = ? AND package_id = ? AND architecture_id = ? AND flag = ?", self.status, self.repo, self.project_id, self.package_id, self.architecture_id, self.flag).exists?
+      errors.add(:flag, "Flag already exists")
+    end
+  end
+
   def to_xml(builder)
     raise RuntimeError.new( "FlagError: No flag-status set. \n #{self.inspect}" ) if self.status.nil?
     options = Hash.new

src/api/app/models/project.rb

@@ -1136,7 +1136,9 @@ def branch_copy_flags(project)
     project.flags.each do |f|
       next if %w(build lock).include?(f.flag)
       next if f.flag == 'publish' and disable_publish_for_branches
-      next if self.flags.where(status: f.status, flag: f.flag, architecture: f.architecture, repo: f.repo).exists?
+      # NOTE: it does not matter if that flag is set to enable or disable, so we do not check fro
+      #       for same flag status here explizit
+      next if self.flags.where(flag: f.flag, architecture: f.architecture, repo: f.repo).exists?
 
       self.flags.create(status: f.status, flag: f.flag, architecture: f.architecture, repo: f.repo)
     end