Add extention to obtain the missing constant from NameError instances

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4679 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 44 insertions, 0 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index c5b4706639..d652e1d17c 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Add extention to obtain the missing constant from NameError instances. [Nicholas Seckar]
+
 * Thoroughly document inflections.  #5700 [petermichaux@gmail.com]
 
 * Added Module#alias_attribute [Jamis/DHH]. Example:
diff --git a/activesupport/lib/active_support/core_ext/name_error.rb b/activesupport/lib/active_support/core_ext/name_error.rb
new file mode 100644
index 0000000000..42b89d3d28
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/name_error.rb
@@ -0,0 +1,15 @@
+
+# Add a +missing_name+ method to NameError instances.
+class NameError < StandardError
+  
+  # Add a method to obtain the missing name from a NameError.
+  def missing_name
+    $1 if /((::)?([A-Z]\w*)(::[A-Z]\w*)*)$/ =~ message
+  end
+  
+  # Was this exception raised because the given name was missing?
+  def missing_name?(name)
+    missing_name == name.to_s
+  end
+  
+end
\ No newline at end of file
diff --git a/activesupport/test/core_ext/name_error_test.rb b/activesupport/test/core_ext/name_error_test.rb
new file mode 100644
index 0000000000..13910d2e01
--- /dev/null
+++ b/activesupport/test/core_ext/name_error_test.rb
@@ -0,0 +1,27 @@
+require 'test/unit'
+require File.dirname(__FILE__) + '/../../lib/active_support/core_ext/name_error'
+
+class NameErrorTest < Test::Unit::TestCase
+  
+  def test_name_error_should_set_missing_name
+    begin
+      SomeNameThatNobodyWillUse____Really ? 1 : 0
+      flunk "?!?!"
+    rescue NameError => exc
+      assert_equal "SomeNameThatNobodyWillUse____Really", exc.missing_name
+      assert exc.missing_name?(:SomeNameThatNobodyWillUse____Really)
+      assert exc.missing_name?("SomeNameThatNobodyWillUse____Really")
+    end
+  end
+  
+  def test_missing_method_should_ignore_missing_name
+    begin
+      some_method_that_does_not_exist
+      flunk "?!?!"
+    rescue NameError => exc
+      assert_equal nil, exc.missing_name
+      assert ! exc.missing_name?(:Foo)
+    end
+  end
+  
+end