bpo-27485: Rename and deprecate undocumented functions in urllib.parse (GH-2205)

diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py
index 5b962f7..9d50b68 100644
--- a/Lib/urllib/request.py
+++ b/Lib/urllib/request.py
@@ -101,9 +101,9 @@
 
 from urllib.error import URLError, HTTPError, ContentTooShortError
 from urllib.parse import (
-    urlparse, urlsplit, urljoin, unwrap, quote, unquote,
-    splittype, splithost, splitport, splituser, splitpasswd,
-    splitattr, splitquery, splitvalue, splittag, to_bytes,
+    urlparse, urlsplit, urljoin, _unwrap, quote, unquote,
+    _splittype, _splithost, _splitport, _splituser, _splitpasswd,
+    _splitattr, _splitquery, _splitvalue, _splittag, _to_bytes,
     unquote_to_bytes, urlunparse)
 from urllib.response import addinfourl, addclosehook
 
@@ -242,7 +242,7 @@
     Returns a tuple containing the path to the newly created
     data file as well as the resulting HTTPMessage object.
     """
-    url_type, path = splittype(url)
+    url_type, path = _splittype(url)
 
     with contextlib.closing(urlopen(url, data)) as fp:
         headers = fp.info()
@@ -349,8 +349,8 @@
     @full_url.setter
     def full_url(self, url):
         # unwrap('<URL:type://host/path>') --> 'type://host/path'
-        self._full_url = unwrap(url)
-        self._full_url, self.fragment = splittag(self._full_url)
+        self._full_url = _unwrap(url)
+        self._full_url, self.fragment = _splittag(self._full_url)
         self._parse()
 
     @full_url.deleter
@@ -378,10 +378,10 @@
         self.data = None
 
     def _parse(self):
-        self.type, rest = splittype(self._full_url)
+        self.type, rest = _splittype(self._full_url)
         if self.type is None:
             raise ValueError("unknown url type: %r" % self.full_url)
-        self.host, self.selector = splithost(rest)
+        self.host, self.selector = _splithost(rest)
         if self.host:
             self.host = unquote(self.host)
 
@@ -768,7 +768,7 @@
     According to RFC 3986, having an authority component means the URL must
     have two slashes after the scheme.
     """
-    scheme, r_scheme = splittype(proxy)
+    scheme, r_scheme = _splittype(proxy)
     if not r_scheme.startswith("/"):
         # authority
         scheme = None
@@ -783,9 +783,9 @@
         if end == -1:
             end = None
         authority = r_scheme[2:end]
-    userinfo, hostport = splituser(authority)
+    userinfo, hostport = _splituser(authority)
     if userinfo is not None:
-        user, password = splitpasswd(userinfo)
+        user, password = _splitpasswd(userinfo)
     else:
         user = password = None
     return scheme, user, password, hostport
@@ -872,7 +872,7 @@
             scheme = None
             authority = uri
             path = '/'
-        host, port = splitport(authority)
+        host, port = _splitport(authority)
         if default_port and port is None and scheme is not None:
             dport = {"http": 80,
                      "https": 443,
@@ -1261,8 +1261,8 @@
 
         sel_host = host
         if request.has_proxy():
-            scheme, sel = splittype(request.selector)
-            sel_host, sel_path = splithost(sel)
+            scheme, sel = _splittype(request.selector)
+            sel_host, sel_path = _splithost(sel)
         if not request.has_header('Host'):
             request.add_unredirected_header('Host', sel_host)
         for name, value in self.parent.addheaders:
@@ -1478,7 +1478,7 @@
                 'Content-type: %s\nContent-length: %d\nLast-modified: %s\n' %
                 (mtype or 'text/plain', size, modified))
             if host:
-                host, port = splitport(host)
+                host, port = _splitport(host)
             if not host or \
                 (not port and _safe_gethostbyname(host) in self.get_names()):
                 if host:
@@ -1503,16 +1503,16 @@
         host = req.host
         if not host:
             raise URLError('ftp error: no host given')
-        host, port = splitport(host)
+        host, port = _splitport(host)
         if port is None:
             port = ftplib.FTP_PORT
         else:
             port = int(port)
 
         # username/password handling
-        user, host = splituser(host)
+        user, host = _splituser(host)
         if user:
-            user, passwd = splitpasswd(user)
+            user, passwd = _splitpasswd(user)
         else:
             passwd = None
         host = unquote(host)
@@ -1523,7 +1523,7 @@
             host = socket.gethostbyname(host)
         except OSError as msg:
             raise URLError(msg)
-        path, attrs = splitattr(req.selector)
+        path, attrs = _splitattr(req.selector)
         dirs = path.split('/')
         dirs = list(map(unquote, dirs))
         dirs, file = dirs[:-1], dirs[-1]
@@ -1533,7 +1533,7 @@
             fw = self.connect_ftp(user, passwd, host, port, dirs, req.timeout)
             type = file and 'I' or 'D'
             for attr in attrs:
-                attr, value = splitvalue(attr)
+                attr, value = _splitvalue(attr)
                 if attr.lower() == 'type' and \
                    value in ('a', 'A', 'i', 'I', 'd', 'D'):
                     type = value.upper()
@@ -1727,19 +1727,19 @@
     # External interface
     def open(self, fullurl, data=None):
         """Use URLopener().open(file) instead of open(file, 'r')."""
-        fullurl = unwrap(to_bytes(fullurl))
+        fullurl = _unwrap(_to_bytes(fullurl))
         fullurl = quote(fullurl, safe="%/:=&?~#+!$,;'@()*[]|")
         if self.tempcache and fullurl in self.tempcache:
             filename, headers = self.tempcache[fullurl]
             fp = open(filename, 'rb')
             return addinfourl(fp, headers, fullurl)
-        urltype, url = splittype(fullurl)
+        urltype, url = _splittype(fullurl)
         if not urltype:
             urltype = 'file'
         if urltype in self.proxies:
             proxy = self.proxies[urltype]
-            urltype, proxyhost = splittype(proxy)
-            host, selector = splithost(proxyhost)
+            urltype, proxyhost = _splittype(proxy)
+            host, selector = _splithost(proxyhost)
             url = (host, fullurl) # Signal special case to open_*()
         else:
             proxy = None
@@ -1763,22 +1763,22 @@
 
     def open_unknown(self, fullurl, data=None):
         """Overridable interface to open unknown URL type."""
-        type, url = splittype(fullurl)
+        type, url = _splittype(fullurl)
         raise OSError('url error', 'unknown url type', type)
 
     def open_unknown_proxy(self, proxy, fullurl, data=None):
         """Overridable interface to open unknown URL type."""
-        type, url = splittype(fullurl)
+        type, url = _splittype(fullurl)
         raise OSError('url error', 'invalid proxy for %s' % type, proxy)
 
     # External interface
     def retrieve(self, url, filename=None, reporthook=None, data=None):
         """retrieve(url) returns (filename, headers) for a local object
         or (tempfilename, headers) for a remote object."""
-        url = unwrap(to_bytes(url))
+        url = _unwrap(_to_bytes(url))
         if self.tempcache and url in self.tempcache:
             return self.tempcache[url]
-        type, url1 = splittype(url)
+        type, url1 = _splittype(url)
         if filename is None and (not type or type == 'file'):
             try:
                 fp = self.open_local_file(url1)
@@ -1853,25 +1853,25 @@
         user_passwd = None
         proxy_passwd= None
         if isinstance(url, str):
-            host, selector = splithost(url)
+            host, selector = _splithost(url)
             if host:
-                user_passwd, host = splituser(host)
+                user_passwd, host = _splituser(host)
                 host = unquote(host)
             realhost = host
         else:
             host, selector = url
             # check whether the proxy contains authorization information
-            proxy_passwd, host = splituser(host)
+            proxy_passwd, host = _splituser(host)
             # now we proceed with the url we want to obtain
-            urltype, rest = splittype(selector)
+            urltype, rest = _splittype(selector)
             url = rest
             user_passwd = None
             if urltype.lower() != 'http':
                 realhost = None
             else:
-                realhost, rest = splithost(rest)
+                realhost, rest = _splithost(rest)
                 if realhost:
-                    user_passwd, realhost = splituser(realhost)
+                    user_passwd, realhost = _splituser(realhost)
                 if user_passwd:
                     selector = "%s://%s%s" % (urltype, realhost, rest)
                 if proxy_bypass(realhost):
@@ -1977,7 +1977,7 @@
         """Use local file."""
         import email.utils
         import mimetypes
-        host, file = splithost(url)
+        host, file = _splithost(url)
         localname = url2pathname(file)
         try:
             stats = os.stat(localname)
@@ -1994,7 +1994,7 @@
             if file[:1] == '/':
                 urlfile = 'file://' + file
             return addinfourl(open(localname, 'rb'), headers, urlfile)
-        host, port = splitport(host)
+        host, port = _splitport(host)
         if (not port
            and socket.gethostbyname(host) in ((localhost(),) + thishost())):
             urlfile = file
@@ -2010,11 +2010,11 @@
         if not isinstance(url, str):
             raise URLError('ftp error: proxy support for ftp protocol currently not implemented')
         import mimetypes
-        host, path = splithost(url)
+        host, path = _splithost(url)
         if not host: raise URLError('ftp error: no host given')
-        host, port = splitport(host)
-        user, host = splituser(host)
-        if user: user, passwd = splitpasswd(user)
+        host, port = _splitport(host)
+        user, host = _splituser(host)
+        if user: user, passwd = _splitpasswd(user)
         else: passwd = None
         host = unquote(host)
         user = unquote(user or '')
@@ -2025,7 +2025,7 @@
             port = ftplib.FTP_PORT
         else:
             port = int(port)
-        path, attrs = splitattr(path)
+        path, attrs = _splitattr(path)
         path = unquote(path)
         dirs = path.split('/')
         dirs, file = dirs[:-1], dirs[-1]
@@ -2047,7 +2047,7 @@
             if not file: type = 'D'
             else: type = 'I'
             for attr in attrs:
-                attr, value = splitvalue(attr)
+                attr, value = _splitvalue(attr)
                 if attr.lower() == 'type' and \
                    value in ('a', 'A', 'i', 'I', 'd', 'D'):
                     type = value.upper()
@@ -2230,11 +2230,11 @@
             return getattr(self,name)(url, realm, data)
 
     def retry_proxy_http_basic_auth(self, url, realm, data=None):
-        host, selector = splithost(url)
+        host, selector = _splithost(url)
         newurl = 'http://' + host + selector
         proxy = self.proxies['http']
-        urltype, proxyhost = splittype(proxy)
-        proxyhost, proxyselector = splithost(proxyhost)
+        urltype, proxyhost = _splittype(proxy)
+        proxyhost, proxyselector = _splithost(proxyhost)
         i = proxyhost.find('@') + 1
         proxyhost = proxyhost[i:]
         user, passwd = self.get_user_passwd(proxyhost, realm, i)
@@ -2248,11 +2248,11 @@
             return self.open(newurl, data)
 
     def retry_proxy_https_basic_auth(self, url, realm, data=None):
-        host, selector = splithost(url)
+        host, selector = _splithost(url)
         newurl = 'https://' + host + selector
         proxy = self.proxies['https']
-        urltype, proxyhost = splittype(proxy)
-        proxyhost, proxyselector = splithost(proxyhost)
+        urltype, proxyhost = _splittype(proxy)
+        proxyhost, proxyselector = _splithost(proxyhost)
         i = proxyhost.find('@') + 1
         proxyhost = proxyhost[i:]
         user, passwd = self.get_user_passwd(proxyhost, realm, i)
@@ -2266,7 +2266,7 @@
             return self.open(newurl, data)
 
     def retry_http_basic_auth(self, url, realm, data=None):
-        host, selector = splithost(url)
+        host, selector = _splithost(url)
         i = host.find('@') + 1
         host = host[i:]
         user, passwd = self.get_user_passwd(host, realm, i)
@@ -2280,7 +2280,7 @@
             return self.open(newurl, data)
 
     def retry_https_basic_auth(self, url, realm, data=None):
-        host, selector = splithost(url)
+        host, selector = _splithost(url)
         i = host.find('@') + 1
         host = host[i:]
         user, passwd = self.get_user_passwd(host, realm, i)
@@ -2502,7 +2502,7 @@
     if no_proxy == '*':
         return 1
     # strip port off host
-    hostonly, port = splitport(host)
+    hostonly, port = _splitport(host)
     # check if the host ends with any of the DNS suffixes
     no_proxy_list = [proxy.strip() for proxy in no_proxy.split(',')]
     for name in no_proxy_list:
@@ -2533,7 +2533,7 @@
     """
     from fnmatch import fnmatch
 
-    hostonly, port = splitport(host)
+    hostonly, port = _splitport(host)
 
     def ip2num(ipAddr):
         parts = ipAddr.split('.')
@@ -2687,7 +2687,7 @@
         if not proxyEnable or not proxyOverride:
             return 0
         # try to make a host list from name and IP address.
-        rawHost, port = splitport(host)
+        rawHost, port = _splitport(host)
         host = [rawHost]
         try:
             addr = socket.gethostbyname(rawHost)