Fix ActiveRecord::Base.compute_type swallowing NoMethodError. [#4751 state:resolved]

Signed-off-by: NDavid Heinemeier Hansson <david@loudthinking.com>

activerecord/CHANGELOG

 *Rails 3.0.0 [beta 4] (June 8th, 2010)*
 
+* Fixed that ActiveRecord::Base.compute_type would swallow NoMethodError #4751 [Andrew Bloomgarden, Andrew White]
+
 * Add index length support for MySQL. #1852 [Emili Parreno, Pratik Naik]
 
   Example:

activerecord/lib/active_record/base.rb

@@ -1219,7 +1219,9 @@ def compute_type(type_name)
               begin
                 constant = candidate.constantize
                 return constant if candidate == constant.to_s
-              rescue NameError
+              rescue NameError => e
+                # We don't want to swallow NoMethodError < NameError errors
+                raise e unless e.instance_of?(NameError)
               rescue ArgumentError
               end
             end

activerecord/test/cases/base_test.rb

@@ -2334,6 +2334,23 @@ def test_dup
     assert !Minimalistic.new.freeze.dup.frozen?
   end
 
+  def test_compute_type_success
+    assert_equal Author, ActiveRecord::Base.send(:compute_type, 'Author')
+  end
+
+  def test_compute_type_nonexistent_constant
+    assert_raises NameError do
+      ActiveRecord::Base.send :compute_type, 'NonexistentModel'
+    end
+  end
+
+  def test_compute_type_no_method_error
+    String.any_instance.stubs(:constantize).raises(NoMethodError)
+    assert_raises NoMethodError do
+      ActiveRecord::Base.send :compute_type, 'InvalidModel'
+    end
+  end
+
   protected
     def with_env_tz(new_tz = 'US/Eastern')
       old_tz, ENV['TZ'] = ENV['TZ'], new_tz