Use the original backtrace for errors in #reset

This will help debugging IOErrors that occur when resetting a
connection.

Fixes #41

History.txt

@@ -4,6 +4,8 @@
   * Added license to gemspec.  Issue #47 by Benjamin Fleischer
   * Set Net::HTTP#keep_alive_timeout when supported by ruby.  Pull request #53
     by Dylan Thacker-Smith.
+  * The backtrace is preserved for errors in #reset to help with debugging.
+    Issue #41 by Andrew Cholakian.
 
 === 2.9 / 2013-07-24
 

lib/net/http/persistent.rb

@@ -956,9 +956,13 @@ def reset connection
 
     start connection
   rescue Errno::ECONNREFUSED
-    raise Error, "connection refused: #{connection.address}:#{connection.port}"
+    e = Error.new "connection refused: #{connection.address}:#{connection.port}"
+    e.set_backtrace $@
+    raise e
   rescue Errno::EHOSTDOWN
-    raise Error, "host down: #{connection.address}:#{connection.port}"
+    e = Error.new "host down: #{connection.address}:#{connection.port}"
+    e.set_backtrace $@
+    raise e
   end
 
   ##

test/test_net_http_persistent.rb

@@ -1339,6 +1339,7 @@ def c.start; raise Errno::EHOSTDOWN end
     end
 
     assert_match %r%host down%, e.message
+    assert_match __FILE__, e.backtrace.first
   end
 
   def test_reset_io_error
@@ -1363,6 +1364,7 @@ def c.start; raise Errno::ECONNREFUSED end
     end
 
     assert_match %r%connection refused%, e.message
+    assert_match __FILE__, e.backtrace.first
   end
 
   def test_retry_change_requests_equals