The exists? class method should treat a string argument as an id rather than as conditions. Closes #5698.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4655 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 25 insertions, 10 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index fddd3e2e4a..e3e6be375f 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* The exists? class method should treat a string argument as an id rather than as conditions.  #5698 [jeremy@planetargon.com]
+
 * Fixed to_xml with :include misbehaviors when invoked on array of model instances #5690 [alexkwolfe@gmail.com]
 
 * Added support for conditions on Base.exists? #5689 [josh@joshpeek.com]. Examples:
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index d704bf5206..40dfb387ce 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -426,10 +426,13 @@ module ActiveRecord #:nodoc:
       # You can also pass a set of SQL conditions. 
       # Example:
       #   Person.exists?(5)
+      #   Person.exists?('5')
       #   Person.exists?(:name => "David")
-      def exists?(conditions)
-        conditions = ["#{primary_key} = ?", conditions] if conditions.is_a?(Fixnum)
-        !find(:first, :conditions => conditions).nil? rescue false
+      #   Person.exists?(['name LIKE ?', "%#{query}%"])
+      def exists?(id_or_conditions)
+        !find(:first, :conditions => expand_id_conditions(id_or_conditions)).nil?
+      rescue ActiveRecord::ActiveRecordError
+        false
       end
 
       # Creates an object, instantly saves it as a record (if the validation permits it), and returns it. If the save
@@ -1224,6 +1227,15 @@ module ActiveRecord #:nodoc:
           end
         end
 
+        # Interpret Array and Hash as conditions and anything else as an id.
+        def expand_id_conditions(id_or_conditions)
+          case id_or_conditions
+            when Array, Hash then id_or_conditions
+            else construct_conditions_from_arguments([primary_key], [id_or_conditions])
+          end
+        end
+
+
         # Defines an "attribute" method (like #inheritance_column or
         # #table_name). A new (class) method will be created with the
         # given name. If a value is specified, the new method will
diff --git a/activerecord/test/finder_test.rb b/activerecord/test/finder_test.rb
index 7e950dac41..626fe137c9 100644
--- a/activerecord/test/finder_test.rb
+++ b/activerecord/test/finder_test.rb
@@ -20,13 +20,14 @@ class FinderTest < Test::Unit::TestCase
   end
   
   def test_exists
-    assert (Topic.exists?(1))
-    assert (Topic.exists?(:author_name => "David"))
-    assert (Topic.exists?(:author_name => "Mary", :approved => true))
-    assert (Topic.exists?(["parent_id = ?", 1]))
-    assert !(Topic.exists?(45))
-    assert !(Topic.exists?("foo"))
-    assert !(Topic.exists?([1,2]))
+    assert Topic.exists?(1)
+    assert Topic.exists?("1")
+    assert Topic.exists?(:author_name => "David")
+    assert Topic.exists?(:author_name => "Mary", :approved => true)
+    assert Topic.exists?(["parent_id = ?", 1])
+    assert !Topic.exists?(45)
+    assert !Topic.exists?("foo")
+    assert_raise(NoMethodError) { Topic.exists?([1,2]) }
   end
   
   def test_find_by_array_of_one_id