From: Tom Hughes <tom@compton.nu>
Date: Fri, 18 Jul 2008 13:13:28 +0000 (+0000)
Subject: Cope with being asked to find relations for any empty set of objects.
X-Git-Tag: live~7750
X-Git-Url: https://git.openstreetmap.org/rails.git/commitdiff_plain/b9fc5e662b5faa738b43f8330ad51b7e366a8c65

Cope with being asked to find relations for any empty set of objects.
---

diff --git a/app/models/relation.rb b/app/models/relation.rb
index 5d7092908..c8516b58a 100644
--- a/app/models/relation.rb
+++ b/app/models/relation.rb
@@ -106,20 +106,32 @@ class Relation < ActiveRecord::Base
   end 
 
   def self.find_for_nodes(ids, options = {})
-    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)
+    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 = {})
-    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)
+    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
 
   def self.find_for_relations(ids, options = {})
-    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)
+    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
   end