Ensure auto_link doesnt linkify URLs in the middle of a tag [#1523 state:resolved]

Signed-off-by: Pratik Naik <pratiknaik@gmail.com>

actionpack/lib/action_view/helpers/text_helper.rb

@@ -536,8 +536,9 @@ module ActionView
           text.gsub(AUTO_LINK_RE) do
             href = $&
             punctuation = ''
-            # detect already linked URLs
-            if $` =~ /<a\s[^>]*href="$/
+            left, right = $`, $'
+            # detect already linked URLs and URLs in the middle of a tag
+            if left =~ /<[^>]+$/ && right =~ /^[^>]*>/
               # do not change string; URL is alreay linked
               href
             else

actionpack/test/template/text_helper_test.rb

@@ -375,6 +375,12 @@ class TextHelperTest < ActionView::TestCase
     assert_equal "{link: #{link3_result}}", auto_link("{link: #{link3_raw}}")
   end
 
+  def test_auto_link_in_tags
+    link_raw    = 'http://www.rubyonrails.org/images/rails.png'
+    link_result = %Q(<img src="#{link_raw}" />)
+    assert_equal link_result, auto_link(link_result)
+  end
+
   def test_auto_link_at_eol
     url1 = "http://api.rubyonrails.com/Foo.html"
     url2 = "http://www.ruby-doc.org/core/Bar.html"