Fix #492 -- Force deterministic ordering of some signals

src/pretix/base/signals.py

@@ -50,7 +50,7 @@ class EventPluginSignal(django.dispatch.Signal):
                 if not hasattr(app, 'compatibility_errors') or not app.compatibility_errors:
                     response = receiver(signal=self, sender=sender, **named)
                     responses.append((receiver, response))
-        return responses
+        return sorted(responses, key=lambda r: (receiver.__module__, receiver.__name__))
 
 
 class DeprecatedSignal(django.dispatch.Signal):

src/pretix/control/context.py

@@ -45,12 +45,12 @@ def contextprocessor(request):
     if not hasattr(request, 'event'):
         for receiver, response in nav_global.send(request, request=request):
             _nav_global += response
-    ctx['nav_global'] = _nav_global
+    ctx['nav_global'] = sorted(_nav_global, key=lambda n: n['label'])
 
     _nav_topbar = []
     for receiver, response in nav_topbar.send(request, request=request):
         _nav_topbar += response
-    ctx['nav_topbar'] = _nav_topbar
+    ctx['nav_topbar'] = sorted(_nav_topbar, key=lambda n: n['label'])
 
     ctx['js_datetime_format'] = get_javascript_format('DATETIME_INPUT_FORMATS')
     ctx['js_date_format'] = get_javascript_format('DATE_INPUT_FORMATS')

src/pretix/control/forms/global_settings.py

@@ -29,7 +29,7 @@ class GlobalSettingsForm(SettingsForm):
             ))
         ])
         responses = register_global_settings.send(self)
-        for r, response in responses:
+        for r, response in sorted(responses, key=lambda r: str(r[0])):
             for key, value in response.items():
                 # We need to be this explicit, since OrderedDict.update does not retain ordering
                 self.fields[key] = value

src/pretix/control/views/event.py

@@ -674,7 +674,7 @@ class EventLive(EventPermissionRequiredMixin, TemplateView):
             issues.append(_('You need to configure at least one quota to sell anything.'))
 
         responses = event_live_issues.send(self.request.event)
-        for receiver, response in responses:
+        for receiver, response in sorted(responses, key=lambda r: str(r[0])):
             if response:
                 issues.append(response)
 

src/pretix/control/views/organizer.py

@@ -48,6 +48,7 @@ class OrganizerDetailViewMixin:
         for recv, retv in nav_organizer.send(sender=self.request.organizer, request=self.request,
                                              organizer=self.request.organizer):
             ctx['nav_organizer'] += retv
+        ctx['nav_organizer'].sort(key=lambda n: n['label'])
         return ctx
 
     def get_object(self, queryset=None) -> Organizer:

src/pretix/plugins/ticketoutputpdf/views.py

@@ -21,7 +21,6 @@ from pretix.control.permissions import EventPermissionRequiredMixin
 from pretix.control.views import ChartContainingView
 from pretix.helpers.database import rolledback_transaction
 from pretix.plugins.ticketoutputpdf.signals import get_fonts
-
 from .ticketoutput import PdfTicketOutput
 
 logger = logging.getLogger(__name__)
@@ -95,7 +94,8 @@ class EditorView(EventPermissionRequiredMixin, ChartContainingView, TemplateView
                 p = order.positions.create(item=item, attendee_name=_("John Doe"), price=item.default_price)
 
                 prov = PdfTicketOutput(request.event,
-                                       override_layout=json.loads(request.POST.get("data")),
+                                       override_layout=(json.loads(request.POST.get("data"))
+                                                        if request.POST.get("data") else None),
                                        override_background=cf.file if cf else None)
                 fname, mimet, data = prov.generate(p)