5 files changed, 28 insertions, 4 deletions
diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 348248e849..e47d291eb3 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *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:
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index aa2826fb33..7cff6d9f1a 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1219,7 +1219,9 @@ module ActiveRecord #:nodoc:
               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
diff --git a/activerecord/test/cases/active_schema_test_mysql.rb b/activerecord/test/cases/active_schema_test_mysql.rb
index 3526f49afd..d7431e5158 100644
--- a/activerecord/test/cases/active_schema_test_mysql.rb
+++ b/activerecord/test/cases/active_schema_test_mysql.rb
@@ -4,6 +4,7 @@ class ActiveSchemaTest < ActiveRecord::TestCase
   def setup
     ActiveRecord::ConnectionAdapters::MysqlAdapter.class_eval do
       alias_method :execute_without_stub, :execute
+      remove_method :execute
       def execute(sql, name = nil) return sql end
     end
   end
@@ -66,7 +67,7 @@ class ActiveSchemaTest < ActiveRecord::TestCase
     assert_equal "DROP TABLE `otherdb`.`people`", drop_table('otherdb.people')
   end
 
-  def test_add_timestamps 
+  def test_add_timestamps
     with_real_execute do
       begin
         ActiveRecord::Base.connection.create_table :delete_me do |t|
@@ -79,8 +80,8 @@ class ActiveSchemaTest < ActiveRecord::TestCase
       end
     end
   end
-  
-  def test_remove_timestamps 
+
+  def test_remove_timestamps
     with_real_execute do
       begin
         ActiveRecord::Base.connection.create_table :delete_me do |t|
@@ -106,6 +107,7 @@ class ActiveSchemaTest < ActiveRecord::TestCase
     ensure
       #before finishing, we restore the alias to the mock-up method
       ActiveRecord::ConnectionAdapters::MysqlAdapter.class_eval do
+        remove_method :execute
         alias_method :execute, :execute_with_stub
       end
     end
diff --git a/activerecord/test/cases/active_schema_test_postgresql.rb b/activerecord/test/cases/active_schema_test_postgresql.rb
index af80f724f2..4f04c6735c 100644
--- a/activerecord/test/cases/active_schema_test_postgresql.rb
+++ b/activerecord/test/cases/active_schema_test_postgresql.rb
@@ -4,6 +4,7 @@ class PostgresqlActiveSchemaTest < Test::Unit::TestCase
   def setup
     ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.class_eval do
       alias_method :real_execute, :execute
+      remove_method :execute
       def execute(sql, name = nil) sql end
     end
   end
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 36c572b5e7..5c175de6d4 100755
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -2334,6 +2334,23 @@ class BasicsTest < ActiveRecord::TestCase
     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