Issue #9974 has been updated by Yui NARUSE.

Priority changed from High to Normal

Thank you for checking trunk version,

You may know, RFC3986 allows underscores in reg-name though DNS name doesn't include underscore. 

```
   host        = IP-literal / IPv4address / reg-name
   reg-name    = *( unreserved / pct-encoded / sub-delims )
   pct-encoded   = "%" HEXDIG HEXDIG

   unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"
   reserved      = gen-delims / sub-delims
   gen-delims    = ":" / "/" / "?" / "#" / "[" / "]" / "@"
   sub-delims    = "!" / "$" / "&" / "'" / "(" / ")"
                 / "*" / "+" / "," / ";" / "="
```

----------------------------------------
Bug #9974: Regression: URI.parse allows invalid URIs
https://bugs.ruby-lang.org/issues/9974#change-47382

* Author: Gabriel Gilder
* Status: Open
* Priority: Normal
* Assignee: 
* Category: lib
* Target version: current: 2.2.0
* ruby -v: ruby 2.2.0dev (2014-06-23 trunk 46517) [x86_64-darwin13]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
~~~
$ ruby -v
ruby 2.2.0dev (2014-06-23 trunk 46517) [x86_64-darwin13]
$ ruby -ruri -e "puts URI.parse('http://test_example')"
http://test_example
~~~

Compare to Ruby 2.1.2:

~~~
$ ruby -v
ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin13.0]
$ ruby -ruri -e "puts URI.parse('http://test_example')"
/Users/gabriel/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/uri/generic.rb:214:in `initialize': the scheme http does not accept registry part: test_example (or bad hostname?) (URI::InvalidURIError)
        from /Users/gabriel/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/uri/http.rb:84:in `initialize'
        from /Users/gabriel/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/uri/common.rb:214:in `new'
        from /Users/gabriel/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/uri/common.rb:214:in `parse'
        from /Users/gabriel/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/uri/common.rb:747:in `parse'
        from -e:1:in `<main>'
~~~

This appears to be a regression as hostnames cannot legally contain underscores: http://en.wikipedia.org/wiki/Hostname#Restrictions%5Fon%5Fvalid%5Fhost%5Fnames





-- 
https://bugs.ruby-lang.org/