Fix Issue9639 - reset the retry count on successful auth.

Lib/urllib/request.py

@@ -778,6 +778,9 @@ class AbstractBasicAuthHandler:
         self.add_password = self.passwd.add_password
         self.retried = 0
 
+    def reset_retry_count(self):
+        self.retried = 0
+
     def http_error_auth_reqed(self, authreq, host, req, headers):
         # host may be an authority (without userinfo) or a URL with an
         # authority
@@ -817,8 +820,10 @@ class HTTPBasicAuthHandler(AbstractBasicAuthHandler, BaseHandler):
 
     def http_error_401(self, req, fp, code, msg, headers):
         url = req.full_url
-        return self.http_error_auth_reqed('www-authenticate',
+        response = self.http_error_auth_reqed('www-authenticate',
                                           url, req, headers)
+        self.reset_retry_count()
+        return response
 
 
 class ProxyBasicAuthHandler(AbstractBasicAuthHandler, BaseHandler):
@@ -831,8 +836,10 @@ class ProxyBasicAuthHandler(AbstractBasicAuthHandler, BaseHandler):
         # should not, RFC 3986 s. 3.2.1) support requests for URLs containing
         # userinfo.
         authority = req.host
-        return self.http_error_auth_reqed('proxy-authenticate',
+        response = self.http_error_auth_reqed('proxy-authenticate',
                                           authority, req, headers)
+        self.reset_retry_count()
+        return response
 
 
 def randombytes(n):