Forgot to backport the rest of #1637.

Lib/urlparse.py

@@ -169,13 +169,12 @@ def _splitparams(url):
     return url[:i], url[i+1:]
 
 def _splitnetloc(url, start=0):
-    for c in '/?#': # the order is important!
-        delim = url.find(c, start)
-        if delim >= 0:
-            break
-    else:
-        delim = len(url)
-    return url[start:delim], url[delim:]
+    delim = len(url)   # position of end of domain part of url, default is end
+    for c in '/?#':    # look for delimiters; the order is NOT important
+        wdelim = url.find(c, start)        # find first of this delim
+        if wdelim >= 0:                    # if found
+            delim = min(delim, wdelim)     # use earliest delim position
+    return url[start:delim], url[delim:]   # return (domain, rest)
 
 def urlsplit(url, scheme='', allow_fragments=True):
     """Parse a URL into 5 components:

Misc/NEWS

@@ -53,6 +53,8 @@ Core and builtins
 Library
 -------
 
+- Patch #1637: fix urlparse for URLs like 'http://x.com?arg=/foo'.
+
 - Issue #1735: TarFile.extractall() now correctly sets directory permissions
   and times.