Senthil, do you read python-dev? I think this change was prematurate from the start (nevermind the fact that you didn't run the test suite before committing).

For example, if you have an URL with a non-ASCII domain name such as "http://وزارة-الأتصالات.مصر/", the domain name should IDNA-encoded, not %-encoded like the rest.

Furthermore, some people are certainly already quoting their URLs to workaround this issue, so "fixing" it will break their code by double-escaping the URLs. You've got to be more careful.