Limit the number of records in Relation#inspect

While it's interesting to have the results array, it can make a console or a webpage freeze if there are a lot of them.
So this limits the number of records displayed in #inspect to 10 and tells how much were effectively found.

activerecord/CHANGELOG.md

@@ -24,12 +24,14 @@
     dealing with a `Relation` object rather than an array:.
 
        User.where(:age => 30).inspect
-       # => <ActiveRecord::Relation [#<User ...>, #<User ...>]>
+       # => <ActiveRecord::Relation [#<User ...>, #<User ...>] ...>
 
        User.where(:age => 30).to_a.inspect
        # => [#<User ...>, #<User ...>]
 
-    *Brian Cardarella & Jon Leighton*
+    The number of records displayed will be limited to 10.
+
+    *Brian Cardarella, Jon Leighton & Damien Mathieu*
 
 *   Add `collation` and `ctype` support to PostgreSQL. These are available for PostgreSQL 8.4 or later.
     Example:

activerecord/lib/active_record/relation.rb

@@ -515,7 +515,19 @@ module ActiveRecord
     end
 
     def inspect
-      "#<#{self.class.name} #{to_a.inspect}>"
+      text = if limit_value && limit_value <= 10
+        to_a.inspect
+      else
+        entries = limit(11).to_a
+        if entries.size > 10
+          entries.pop
+          "[#{entries.map(&:inspect).join(', ')}, ...]"
+        else
+          entries.inspect
+        end
+      end
+
+      "#<#{self.class.name} #{text}>"
     end
 
     private

activerecord/test/cases/relations_test.rb

@@ -1316,4 +1316,9 @@ class RelationTest < ActiveRecord::TestCase
     relation = Post.limit(2)
     assert_equal "#<ActiveRecord::Relation [#{Post.limit(2).map(&:inspect).join(', ')}]>", relation.inspect
   end
+
+  test "relations limits the records in #inspect at 10" do
+    relation = Post.limit(11)
+    assert_equal "#<ActiveRecord::Relation [#{Post.limit(10).map(&:inspect).join(', ')}, ...]>", relation.inspect
+  end
 end