Convert params to Model.find(id) to whatever the _id field type is de…

…fined as, no matter what the type. Closes #1380.

CHANGELOG.md

@@ -32,6 +32,9 @@ For instructions on upgrading to newer versions, visit
 
 * \#1387 Added `Model#cache_key` for use in Rails caching. (Seivan Heidari)
 
+* \#1380 Calling Model.find(id) will now properly convert to and from any type
+  based on the type of the _id field.
+
 ### Resolved Issues
 
 * \#1463 Batch insert consumers are now scoped to collection to avoid persistence

lib/mongoid/criterion/optional.rb

@@ -89,11 +89,12 @@ def extras(extras)
       #
       # @return [ Criteria ] The cloned criteria.
       def for_ids(*ids)
+        field = klass.fields["_id"]
         ids.flatten!
         if ids.size > 1
-          where(:_id.in => ::BSON::ObjectId.convert(klass, ids))
+          any_in(:_id => ids.map{ |id| field.serialize(id) })
         else
-          where(:_id => ids.first)
+          where(:_id => field.serialize(ids.first))
         end
       end
 

spec/functional/mongoid/criteria_spec.rb

@@ -80,9 +80,7 @@
       end
 
       it 'should find the object with a matching BSON::ObjectId argument' do
-        expect {
-          Person.find(BSON::ObjectId(person.id))
-        }.to raise_error
+        Person.find(BSON::ObjectId(person.id)).should eq(person)
       end
     end
   end

spec/functional/mongoid/finders_spec.rb

@@ -8,6 +8,47 @@
 
   describe "#find" do
 
+    context "when using integer ids" do
+
+      before(:all) do
+        Person.identity :type => Integer
+      end
+
+      after(:all) do
+        Person.identity :type => BSON::ObjectId
+      end
+
+      context "when passed a string" do
+
+        let!(:person) do
+          Person.create(:_id => 1, :ssn => "123-44-4321")
+        end
+
+        let(:from_db) do
+          Person.find("1")
+        end
+
+        it "returns the matching document" do
+          from_db.should eq(person)
+        end
+      end
+
+      context "when passed an array of strings" do
+
+        let!(:person) do
+          Person.create(:_id => 2, :ssn => "123-44-4321")
+        end
+
+        let(:from_db) do
+          Person.find([ "2" ])
+        end
+
+        it "returns the matching documents" do
+          from_db.should eq([ person ])
+        end
+      end
+    end
+
     context "when using string ids" do
 
       let!(:person) do

spec/unit/mongoid/criterion/optional_spec.rb

@@ -342,8 +342,8 @@
             base.for_ids(id)
           end
 
-          it "adds the _id query to the selector" do
-            criteria.selector.should eq({ :_id => id })
+          it "adds the string _id query to the selector" do
+            criteria.selector.should eq({ :_id => id.to_s })
           end
 
           it "returns a copy" do
@@ -375,7 +375,7 @@
         end
 
         it "adds the _id query to the selector" do
-          base.for_ids(ids).selector.should eq({ :_id => ids.first })
+          base.for_ids(ids).selector.should eq({ :_id => ids.first.to_s })
         end
       end
     end