sslutil: synchronize hostname matching logic with CPython sslutil contains its own hostname matching logic. CPython has code for the same intent. However, it is only available to Python 2.7.9+ (or distributions that have backported 2.7.9's ssl module improvements). This patch effectively imports CPython's hostname matching code from its ssl.py into sslutil.py. The hostname matching code itself is pretty similar. However, the DNS name matching code is much more robust and spec conformant. As the test changes show, this changes some behavior around wildcard handling and IDNA matching. The new behavior allows wildcards in the middle of words (e.g. 'f*.com' matches 'foo.com') This is spec compliant according to RFC 6125 Section 6.5.3 item 3. There is one test where the matcher is more strict. Before, '*.a.com' matched '.a.com'. Now it doesn't match. Strictly speaking this is a security vulnerability.

  $ hg init
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ ls
  a
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"
  $ hg co 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

B should disappear

  $ ls
  a