Remove references to libpgosm during travis runs

[rails.git] / app / models / relation.rb

diff --git a/app/models/relation.rb b/app/models/relation.rb
index 36d6943d97106e9ecfd42242fc8575c1932839e2..dc2b71ac4193f292ea6febf9e9df8176cc606647 100644 (file)
--- a/app/models/relation.rb
+++ b/app/models/relation.rb
@@ -1,244 +1,204 @@
+# == Schema Information
+#
+# Table name: current_relations
+#
+#  id           :bigint(8)        not null, primary key
+#  changeset_id :bigint(8)        not null
+#  timestamp    :datetime         not null
+#  visible      :boolean          not null
+#  version      :bigint(8)        not null
+#
+# Indexes
+#
+#  current_relations_timestamp_idx  (timestamp)
+#
+# Foreign Keys
+#
+#  current_relations_changeset_id_fkey  (changeset_id => changesets.id)
+#
+

 class Relation < ActiveRecord::Base
 class Relation < ActiveRecord::Base

-  require 'xml/libxml'
-  
+  require "xml/libxml"
+

   include ConsistencyValidations
   include ConsistencyValidations

-  
-  set_table_name 'current_relations'
+  include NotRedactable
+  include ObjectMetadata
+
+  self.table_name = "current_relations"

 
   belongs_to :changeset
 
 
   belongs_to :changeset
 

-  has_many :old_relations, :foreign_key => 'id', :order => 'version'
+  has_many :old_relations, -> { order(:version) }

 
 

-  has_many :relation_members, :foreign_key => 'id', :order => 'sequence_id'
-  has_many :relation_tags, :foreign_key => 'id'
+  has_many :relation_members, -> { order(:sequence_id) }
+  has_many :relation_tags

 
   has_many :containing_relation_members, :class_name => "RelationMember", :as => :member
 
   has_many :containing_relation_members, :class_name => "RelationMember", :as => :member

-  has_many :containing_relations, :class_name => "Relation", :through => :containing_relation_members, :source => :relation, :extend => ObjectFinder
-
-  validates_presence_of :id, :on => :update
-  validates_presence_of :timestamp,:version,  :changeset_id 
-  validates_uniqueness_of :id
-  validates_inclusion_of :visible, :in => [ true, false ]
-  validates_numericality_of :id, :on => :update, :integer_only => true
-  validates_numericality_of :changeset_id, :version, :integer_only => true
-  validates_associated :changeset
-  
-  TYPES = ["node", "way", "relation"]
-
-  def self.from_xml(xml, create=false)
-    begin
-      p = XML::Parser.string(xml)
-      doc = p.parse
-
-      doc.find('//osm/relation').each do |pt|
-        return Relation.from_xml_node(pt, create)
-      end
-    rescue LibXML::XML::Error, ArgumentError => ex
-      raise OSM::APIBadXMLError.new("relation", xml, ex.message)
+  has_many :containing_relations, :class_name => "Relation", :through => :containing_relation_members, :source => :relation
+
+  validates :id, :uniqueness => true, :presence => { :on => :update },
+                 :numericality => { :on => :update, :only_integer => true }
+  validates :version, :presence => true,
+                      :numericality => { :only_integer => true }
+  validates :changeset_id, :presence => true,
+                           :numericality => { :only_integer => true }
+  validates :timestamp, :presence => true
+  validates :changeset, :associated => true
+  validates :visible, :inclusion => [true, false]
+
+  scope :visible, -> { where(:visible => true) }
+  scope :invisible, -> { where(:visible => false) }
+  scope :nodes, ->(*ids) { joins(:relation_members).where(:current_relation_members => { :member_type => "Node", :member_id => ids.flatten }) }
+  scope :ways, ->(*ids) { joins(:relation_members).where(:current_relation_members => { :member_type => "Way", :member_id => ids.flatten }) }
+  scope :relations, ->(*ids) { joins(:relation_members).where(:current_relation_members => { :member_type => "Relation", :member_id => ids.flatten }) }
+
+  TYPES = %w[node way relation].freeze
+
+  def self.from_xml(xml, create = false)
+    p = XML::Parser.string(xml, :options => XML::Parser::Options::NOERROR)
+    doc = p.parse
+
+    doc.find("//osm/relation").each do |pt|
+      return Relation.from_xml_node(pt, create)

     end
     end

+    raise OSM::APIBadXMLError.new("node", xml, "XML doesn't contain an osm/relation element.")
+  rescue LibXML::XML::Error, ArgumentError => e
+    raise OSM::APIBadXMLError.new("relation", xml, e.message)

   end
 
   end
 

-  def self.from_xml_node(pt, create=false)
+  def self.from_xml_node(pt, create = false)

     relation = Relation.new
 
     relation = Relation.new
 

-    if !create and pt['id'] != '0'
-      relation.id = pt['id'].to_i
-    end
+    raise OSM::APIBadXMLError.new("relation", pt, "Version is required when updating") unless create || !pt["version"].nil?

 
 

-    raise OSM::APIBadXMLError.new("relation", pt, "You are missing the required changeset in the relation") if pt['changeset'].nil?
-    relation.changeset_id = pt['changeset']
-
-    # The follow block does not need to be executed because they are dealt with 
-    # in create_with_history, update_from and delete_with_history
-    if create
-      relation.timestamp = Time.now.getutc
-      relation.visible = true
-      relation.version = 0
-    else
-      if pt['timestamp']
-        relation.timestamp = Time.parse(pt['timestamp'])
-      end
-      relation.version = pt['version']
+    relation.version = pt["version"]
+    raise OSM::APIBadXMLError.new("relation", pt, "Changeset id is missing") if pt["changeset"].nil?
+
+    relation.changeset_id = pt["changeset"]
+
+    unless create
+      raise OSM::APIBadXMLError.new("relation", pt, "ID is required when updating") if pt["id"].nil?
+
+      relation.id = pt["id"].to_i
+      # .to_i will return 0 if there is no number that can be parsed.
+      # We want to make sure that there is no id with zero anyway
+      raise OSM::APIBadUserInput, "ID of relation cannot be zero when updating." if relation.id.zero?

     end
 
     end
 

-    pt.find('tag').each do |tag|
-      relation.add_tag_keyval(tag['k'], tag['v'])
+    # We don't care about the timestamp nor the visibility as these are either
+    # set explicitly or implicit in the action. The visibility is set to true,
+    # and manually set to false before the actual delete.
+    relation.visible = true
+
+    # Start with no tags
+    relation.tags = {}
+
+    # Add in any tags from the XML
+    pt.find("tag").each do |tag|
+      raise OSM::APIBadXMLError.new("relation", pt, "tag is missing key") if tag["k"].nil?
+      raise OSM::APIBadXMLError.new("relation", pt, "tag is missing value") if tag["v"].nil?
+
+      relation.add_tag_keyval(tag["k"], tag["v"])

     end
 
     end
 

-    pt.find('member').each do |member|
-      #member_type = 
-      logger.debug "each member"
-      raise OSM::APIBadXMLError.new("relation", pt, "The #{member['type']} is not allowed only, #{TYPES.inspect} allowed") unless TYPES.include? member['type']
-      logger.debug "after raise"
-      #member_ref = member['ref']
-      #member_role
-      member['role'] ||= "" # Allow  the upload to not include this, in which case we default to an empty string.
-      logger.debug member['role']
-      relation.add_member(member['type'].classify, member['ref'], member['role'])
+    # need to initialise the relation members array explicitly, as if this
+    # isn't done for a new relation then @members attribute will be nil,
+    # and the members will be loaded from the database instead of being
+    # empty, as intended.
+    relation.members = []
+
+    pt.find("member").each do |member|
+      # member_type =
+      raise OSM::APIBadXMLError.new("relation", pt, "The #{member['type']} is not allowed only, #{TYPES.inspect} allowed") unless TYPES.include? member["type"]
+
+      # member_ref = member['ref']
+      # member_role
+      member["role"] ||= "" # Allow  the upload to not include this, in which case we default to an empty string.
+      relation.add_member(member["type"].classify, member["ref"], member["role"])

     end
     end

-    raise OSM::APIBadUserInput.new("Some bad xml in relation") if relation.nil?
+    raise OSM::APIBadUserInput, "Some bad xml in relation" if relation.nil?

 
 

-    return relation
+    relation

   end
 
   def to_xml
     doc = OSM::API.new.get_xml_doc
   end
 
   def to_xml
     doc = OSM::API.new.get_xml_doc

-    doc.root << to_xml_node()
-    return doc
+    doc.root << to_xml_node
+    doc

   end
 
   end
 

-  def to_xml_node(user_display_name_cache = nil)
-    el1 = XML::Node.new 'relation'
-    el1['id'] = self.id.to_s
-    el1['visible'] = self.visible.to_s
-    el1['timestamp'] = self.timestamp.xmlschema
-    el1['version'] = self.version.to_s
-    el1['changeset'] = self.changeset_id.to_s
-
-    user_display_name_cache = {} if user_display_name_cache.nil?
-    
-    if user_display_name_cache and user_display_name_cache.key?(self.changeset.user_id)
-      # use the cache if available
-    elsif self.changeset.user.data_public?
-      user_display_name_cache[self.changeset.user_id] = self.changeset.user.display_name
-    else
-      user_display_name_cache[self.changeset.user_id] = nil
-    end
-
-    if not user_display_name_cache[self.changeset.user_id].nil?
-      el1['user'] = user_display_name_cache[self.changeset.user_id]
-      el1['uid'] = self.changeset.user_id.to_s
-    end
+  def to_xml_node(changeset_cache = {}, user_display_name_cache = {})
+    el = XML::Node.new "relation"
+    el["id"] = id.to_s

 
 

-    self.relation_members.each do |member|
-      p=0
-      #if visible_members
-      #  # if there is a list of visible members then use that to weed out deleted segments
-      #  if visible_members[member.member_type][member.member_id]
-      #    p=1
-      #  end
-      #else
-        # otherwise, manually go to the db to check things
-        if member.member.visible?
-          p=1
-        end
-      #end
-      if p
-        e = XML::Node.new 'member'
-        e['type'] = member.member_type.downcase
-        e['ref'] = member.member_id.to_s 
-        e['role'] = member.member_role
-        el1 << e
-       end
-    end
+    add_metadata_to_xml_node(el, self, changeset_cache, user_display_name_cache)

 
 

-    self.relation_tags.each do |tag|
-      e = XML::Node.new 'tag'
-      e['k'] = tag.k
-      e['v'] = tag.v
-      el1 << e
+    relation_members.each do |member|
+      member_el = XML::Node.new "member"
+      member_el["type"] = member.member_type.downcase
+      member_el["ref"] = member.member_id.to_s
+      member_el["role"] = member.member_role
+      el << member_el

     end
     end

-    return el1
-  end 
-
-  def self.find_for_nodes(ids, options = {})
-    if ids.empty?
-      return []
-    else
-      self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'Node' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
-        return self.find(:all, options)
-      end
-    end
-  end

 
 

-  def self.find_for_ways(ids, options = {})
-    if ids.empty?
-      return []
-    else
-      self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'Way' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
-        return self.find(:all, options)
-      end
-    end
-  end
+    add_tags_to_xml_node(el, relation_tags)

 
 

-  def self.find_for_relations(ids, options = {})
-    if ids.empty?
-      return []
-    else
-      self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'Relation' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
-        return self.find(:all, options)
-      end
-    end
+    el

   end
 
   end
 

-  # FIXME is this really needed?
+  # FIXME: is this really needed?

   def members
   def members

-    unless @members
-      @members = Array.new
-      self.relation_members.each do |member|
-        @members += [[member.member_type,member.member_id,member.member_role]]
-      end
+    @members ||= relation_members.map do |member|
+      [member.member_type, member.member_id, member.member_role]

     end
     end

-    @members

   end
 
   def tags
   end
 
   def tags

-    unless @tags
-      @tags = Hash.new
-      self.relation_tags.each do |tag|
-        @tags[tag.k] = tag.v
-      end
-    end
-    @tags
+    @tags ||= Hash[relation_tags.collect { |t| [t.k, t.v] }]

   end
 
   end
 

-  def members=(m)
-    @members = m
-  end
+  attr_writer :members

 
 

-  def tags=(t)
-    @tags = t
-  end
+  attr_writer :tags

 
 

-  def add_member(type,id,role)
-    @members = Array.new unless @members
-    @members += [[type,id,role]]
+  def add_member(type, id, role)
+    @members ||= []
+    @members << [type, id.to_i, role]

   end
 
   def add_tag_keyval(k, v)
   end
 
   def add_tag_keyval(k, v)

-    @tags = Hash.new unless @tags
+    @tags ||= {}

 
     # duplicate tags are now forbidden, so we can't allow values
     # in the hash to be overwritten.
 
     # duplicate tags are now forbidden, so we can't allow values
     # in the hash to be overwritten.

-    raise OSM::APIDuplicateTagsError.new("relation", self.id, k) if @tags.include? k
+    raise OSM::APIDuplicateTagsError.new("relation", id, k) if @tags.include? k

 
     @tags[k] = v
   end
 
   ##
 
     @tags[k] = v
   end
 
   ##

-  # updates the changeset bounding box to contain the bounding box of 
+  # updates the changeset bounding box to contain the bounding box of

   # the element with given +type+ and +id+. this only works with nodes
   # and ways at the moment, as they're the only elements to respond to
   # the :bbox call.
   def update_changeset_element(type, id)
     element = Kernel.const_get(type.capitalize).find(id)
     changeset.update_bbox! element.bbox
   # the element with given +type+ and +id+. this only works with nodes
   # and ways at the moment, as they're the only elements to respond to
   # the :bbox call.
   def update_changeset_element(type, id)
     element = Kernel.const_get(type.capitalize).find(id)
     changeset.update_bbox! element.bbox

-  end    
+  end

 
   def delete_with_history!(new_relation, user)
 
   def delete_with_history!(new_relation, user)

-    unless self.visible
-      raise OSM::APIAlreadyDeletedError.new
-    end
+    raise OSM::APIAlreadyDeletedError.new("relation", new_relation.id) unless visible

 
 

-    # need to start the transaction here, so that the database can 
+    # need to start the transaction here, so that the database can

     # provide repeatable reads for the used-by checks. this means it
     # shouldn't be possible to get race conditions.
     Relation.transaction do
     # provide repeatable reads for the used-by checks. this means it
     # shouldn't be possible to get race conditions.
     Relation.transaction do

+      lock!

       check_consistency(self, new_relation, user)
       # This will check to see if this relation is used by another relation
       check_consistency(self, new_relation, user)
       # This will check to see if this relation is used by another relation

-      if RelationMember.find(:first, :joins => "INNER JOIN current_relations ON current_relations.id=current_relation_members.id", :conditions => [ "visible = ? AND member_type='Relation' and member_id=? ", true, self.id ])
-        raise OSM::APIPreconditionFailedError.new("The relation #{new_relation.id} is a used in another relation")
-      end
+      rel = RelationMember.joins(:relation).find_by("visible = ? AND member_type = 'Relation' and member_id = ? ", true, id)
+      raise OSM::APIPreconditionFailedError, "The relation #{new_relation.id} is used in relation #{rel.relation.id}." unless rel.nil?
+

       self.changeset_id = new_relation.changeset_id
       self.tags = {}
       self.members = []
       self.changeset_id = new_relation.changeset_id
       self.tags = {}
       self.members = []


@@ -248,76 +208,77 @@ class Relation < ActiveRecord::Base
   end
 
   def update_from(new_relation, user)
   end
 
   def update_from(new_relation, user)

-    check_consistency(self, new_relation, user)
-    if !new_relation.preconditions_ok?
-      raise OSM::APIPreconditionFailedError.new
+    Relation.transaction do
+      lock!
+      check_consistency(self, new_relation, user)
+      raise OSM::APIPreconditionFailedError, "Cannot update relation #{id}: data or member data is invalid." unless new_relation.preconditions_ok?(members)
+
+      self.changeset_id = new_relation.changeset_id
+      self.changeset = new_relation.changeset
+      self.tags = new_relation.tags
+      self.members = new_relation.members
+      self.visible = true
+      save_with_history!

     end
     end

-    self.changeset_id = new_relation.changeset_id
-    self.changeset = new_relation.changeset
-    self.tags = new_relation.tags
-    self.members = new_relation.members
-    self.visible = true
-    save_with_history!

   end
   end

-  
+

   def create_with_history(user)
     check_create_consistency(self, user)
   def create_with_history(user)
     check_create_consistency(self, user)

-    if !self.preconditions_ok?
-      raise OSM::APIPreconditionFailedError.new
-    end
+    raise OSM::APIPreconditionFailedError, "Cannot create relation: data or member data is invalid." unless preconditions_ok?
+

     self.version = 0
     self.visible = true
     save_with_history!
   end
 
     self.version = 0
     self.visible = true
     save_with_history!
   end
 

-  def preconditions_ok?
-    # These are hastables that store an id in the index of all 
+  def preconditions_ok?(good_members = [])
+    # These are hastables that store an id in the index of all

     # the nodes/way/relations that have already been added.
     # the nodes/way/relations that have already been added.

-    # If the member is valid and visible then we add it to the 
+    # If the member is valid and visible then we add it to the

     # relevant hash table, with the value true as a cache.
     # Thus if you have nodes with the ids of 50 and 1 already in the
     # relation, then the hash table nodes would contain:
     # => {50=>true, 1=>true}
     # relevant hash table, with the value true as a cache.
     # Thus if you have nodes with the ids of 50 and 1 already in the
     # relation, then the hash table nodes would contain:
     # => {50=>true, 1=>true}

-    elements = { :node => Hash.new, :way => Hash.new, :relation => Hash.new }
-    self.members.each do |m|
+    elements = { :node => {}, :way => {}, :relation => {} }
+
+    # pre-set all existing members to good
+    good_members.each { |m| elements[m[0].downcase.to_sym][m[1]] = true }
+
+    members.each do |m|

       # find the hash for the element type or die
       # find the hash for the element type or die

-      logger.debug m[0]
-      hash = elements[m[0].downcase.to_sym] or return false
+      hash = elements[m[0].downcase.to_sym]
+      return false unless hash
+

       # unless its in the cache already
       # unless its in the cache already

-      unless hash.key? m[1]
-        # use reflection to look up the appropriate class
-        model = Kernel.const_get(m[0].capitalize)
-        # get the element with that ID
-        element = model.find(m[1])
-
-        # and check that it is OK to use.
-        unless element and element.visible? and element.preconditions_ok?
-          return false
-        end
-        hash[m[1]] = true
-      end
-    end
+      next if hash.key? m[1]

 
 

-    return true
-  rescue
-    return false
-  end
+      # use reflection to look up the appropriate class
+      model = Kernel.const_get(m[0].capitalize)
+      # get the element with that ID. and, if found, lock the element to
+      # ensure it can't be deleted until after the current transaction
+      # commits.
+      element = model.lock("for share").find_by(:id => m[1])
+
+      # and check that it is OK to use.
+      raise OSM::APIPreconditionFailedError, "Relation with id #{id} cannot be saved due to #{m[0]} with id #{m[1]}" unless element&.visible? && element&.preconditions_ok?
+
+      hash[m[1]] = true
+    end

 
 

-  # Temporary method to match interface to nodes
-  def tags_as_hash
-    return self.tags
+    true

   end
 
   ##
   # if any members are referenced by placeholder IDs (i.e: negative) then
   end
 
   ##
   # if any members are referenced by placeholder IDs (i.e: negative) then

-  # this calling this method will fix them using the map from placeholders 
-  # to IDs +id_map+. 
-  def fix_placeholders!(id_map)
-    self.members.map! do |type, id, role|
+  # this calling this method will fix them using the map from placeholders
+  # to IDs +id_map+.
+  def fix_placeholders!(id_map, placeholder_id = nil)
+    members.map! do |type, id, role|

       old_id = id.to_i
       old_id = id.to_i

-      if old_id < 0
+      if old_id.negative?

         new_id = id_map[type.downcase.to_sym][old_id]
         new_id = id_map[type.downcase.to_sym][old_id]

-        raise "invalid placeholder" if new_id.nil?
+        raise OSM::APIBadUserInput, "Placeholder #{type} not found for reference #{old_id} in relation #{self.id.nil? ? placeholder_id : self.id}." if new_id.nil?
+

         [type, new_id, role]
       else
         [type, id, role]
         [type, new_id, role]
       else
         [type, id, role]


@@ -326,31 +287,31 @@ class Relation < ActiveRecord::Base
   end
 
   private
   end
 
   private

-  
+

   def save_with_history!
   def save_with_history!

+    t = Time.now.getutc
+
+    self.version += 1
+    self.timestamp = t
+

     Relation.transaction do
       # have to be a little bit clever here - to detect if any tags
       # changed then we have to monitor their before and after state.
       tags_changed = false
 
     Relation.transaction do
       # have to be a little bit clever here - to detect if any tags
       # changed then we have to monitor their before and after state.
       tags_changed = false
 

-      t = Time.now.getutc
-      self.version += 1
-      self.timestamp = t
-      self.save!
+      # clone the object before saving it so that the original is
+      # still marked as dirty if we retry the transaction
+      clone.save!

 
 

-      tags = self.tags
-      self.relation_tags.each do |old_tag|
+      tags = self.tags.clone
+      relation_tags.each do |old_tag|

         key = old_tag.k
         # if we can match the tags we currently have to the list
         # of old tags, then we never set the tags_changed flag. but
         key = old_tag.k
         # if we can match the tags we currently have to the list
         # of old tags, then we never set the tags_changed flag. but

-        # if any are different then set the flag and do the DB 
+        # if any are different then set the flag and do the DB

         # update.
         # update.

-        if tags.has_key? key 
-          # rails 2.1 dirty handling should take care of making this
-          # somewhat efficient... hopefully...
-          old_tag.v = tags[key]
-          tags_changed |= old_tag.changed?
-          old_tag.save!
+        if tags.key? key
+          tags_changed |= (old_tag.v != tags[key])

 
           # remove from the map, so that we can expect an empty map
           # at the end if there are no new tags
 
           # remove from the map, so that we can expect an empty map
           # at the end if there are no new tags


@@ -359,52 +320,46 @@ class Relation < ActiveRecord::Base
         else
           # this means a tag was deleted
           tags_changed = true
         else
           # this means a tag was deleted
           tags_changed = true

-          RelationTag.delete_all ['id = ? and k = ?', self.id, old_tag.k]

         end
       end
       # if there are left-over tags then they are new and will have to
       # be added.
         end
       end
       # if there are left-over tags then they are new and will have to
       # be added.

-      tags_changed |= (not tags.empty?)
-      tags.each do |k,v|
+      tags_changed |= !tags.empty?
+      RelationTag.where(:relation_id => id).delete_all
+      self.tags.each do |k, v|

         tag = RelationTag.new
         tag = RelationTag.new

+        tag.relation_id = id

         tag.k = k
         tag.v = v
         tag.k = k
         tag.v = v

-        tag.id = self.id

         tag.save!
       end
         tag.save!
       end

-      
-      # reload, so that all of the members are accessible in their
-      # new state.
-      self.reload

 
       # same pattern as before, but this time we're collecting the
       # changed members in an array, as the bounding box updates for
       # elements are per-element, not blanked on/off like for tags.
 
       # same pattern as before, but this time we're collecting the
       # changed members in an array, as the bounding box updates for
       # elements are per-element, not blanked on/off like for tags.

-      changed_members = Array.new
-      members = Hash.new
-      self.members.each do |m|
-        # should be: h[[m.id, m.type]] = m.role, but someone prefers arrays
-        members[[m[1], m[0]]] = m[2]
-      end
+      changed_members = []
+      members = self.members.clone

       relation_members.each do |old_member|
       relation_members.each do |old_member|

-        key = [old_member.member_id.to_s, old_member.member_type]
-        if members.has_key? key
-          members.delete key
-        else
+        key = [old_member.member_type, old_member.member_id, old_member.member_role]
+        i = members.index key
+        if i.nil?

           changed_members << key
           changed_members << key

+        else
+          members.delete_at i

         end
       end
       # any remaining members must be new additions
         end
       end
       # any remaining members must be new additions

-      changed_members += members.keys
+      changed_members += members

 
       # update the members. first delete all the old members, as the new
       # members may be in a different order and i don't feel like implementing
       # a longest common subsequence algorithm to optimise this.
       members = self.members
 
       # update the members. first delete all the old members, as the new
       # members may be in a different order and i don't feel like implementing
       # a longest common subsequence algorithm to optimise this.
       members = self.members

-      RelationMember.delete_all(:id => self.id)
-      members.each_with_index do |m,i|
+      RelationMember.where(:relation_id => id).delete_all
+      members.each_with_index do |m, i|

         mem = RelationMember.new
         mem = RelationMember.new

-        mem.id = [self.id, i]
+        mem.relation_id = id
+        mem.sequence_id = i

         mem.member_type = m[0]
         mem.member_id = m[1]
         mem.member_role = m[2]
         mem.member_type = m[0]
         mem.member_id = m[1]
         mem.member_role = m[2]


@@ -425,26 +380,22 @@ class Relation < ActiveRecord::Base
       # bounding box. this is similar to how the map call does things and is
       # reasonable on the assumption that adding or removing members doesn't
       # materially change the rest of the relation.
       # bounding box. this is similar to how the map call does things and is
       # reasonable on the assumption that adding or removing members doesn't
       # materially change the rest of the relation.

-      any_relations = 
-        changed_members.collect { |id,type| type == "relation" }.
-        inject(false) { |b,s| b or s }
-
-      if tags_changed or any_relations
-        # add all non-relation bounding boxes to the changeset
-        # FIXME: check for tag changes along with element deletions and
-        # make sure that the deleted element's bounding box is hit.
-        self.members.each do |type, id, role|
-          if type != "Relation"
-            update_changeset_element(type, id)
-          end
-        end
-      else
-        # add only changed members to the changeset
-        changed_members.each do |id, type|
-          if type != "Relation"
-            update_changeset_element(type, id)
-          end
-        end
+      any_relations =
+        changed_members.collect { |type, _id, _role| type == "Relation" }
+                       .inject(false) { |acc, elem| acc || elem }
+
+      # if the relation is being deleted tags_changed will be true and members empty
+      # so we need to use changed_members to create a correct bounding box
+      update_members = if visible && (tags_changed || any_relations)
+                         # add all non-relation bounding boxes to the changeset
+                         # FIXME: check for tag changes along with element deletions and
+                         # make sure that the deleted element's bounding box is hit.
+                         self.members
+                       else
+                         changed_members
+                       end
+      update_members.each do |type, id, _role|
+        update_changeset_element(type, id) if type != "Relation"

       end
 
       # tell the changeset we updated one element only
       end
 
       # tell the changeset we updated one element only


@@ -454,5 +405,4 @@ class Relation < ActiveRecord::Base
       changeset.save!
     end
   end
       changeset.save!
     end
   end

-

 end
 end