views: force fc-register to always redirect post registration to fc-login-or-link (fixes #19270)

Without it linking to FC does not happen

src/authentic2_auth_fc/views.py

@@ -2,7 +2,8 @@ import uuid
 import requests
 import logging
 import json
-
+import urlparse
+import urllib
 
 from requests_oauthlib import OAuth2Session
 
@@ -415,6 +416,14 @@ class RegistrationView(LoggerMixin, View):
         redirect_to = request.GET.get(REDIRECT_FIELD_NAME, '')
         if not is_safe_url(url=redirect_to, host=request.get_host()):
             redirect_to = resolve_url(settings.LOGIN_REDIRECT_URL)
+
+        # Prevent errors when redirect_to does not contain fc-login-or-link view
+        parsed_redirect_to = urlparse.urlparse(redirect_to)
+        if parsed_redirect_to.path != reverse('fc-login-or-link'):
+            redirect_to = '%s?%s=%s' % (
+                reverse('fc-login-or-link'),
+                REDIRECT_FIELD_NAME,
+                urllib.quote(redirect_to))
         if not 'email' in data:
             data[REDIRECT_FIELD_NAME] = redirect_to
             messages.info(request, _("FranceConnect didn't provide your email address, please do."))
@@ -422,10 +431,9 @@ class RegistrationView(LoggerMixin, View):
                                                              signing.dumps(data)))
         data['valid_email'] = False
         data['franceconnect'] = True
-        activation_url = \
-            a2_utils.build_activation_url(request,
-                                          next_url=redirect_to,
-                                          **data)
+        activation_url = a2_utils.build_activation_url(request,
+                                                       next_url=redirect_to,
+                                                       **data)
         return HttpResponseRedirect(activation_url)