Properly reset substitutions on new requests

wcs/qommon/publisher.py

@@ -364,6 +364,7 @@ class QommonPublisher(Publisher):
         self.set_config(request)
         request.language = self.get_site_language()
         self.install_lang(request.language)
+        self.substitutions.reset()
         self.substitutions.feed(self)
         return Publisher.try_publish(self, request)
 

wcs/qommon/substitution.py

@@ -43,6 +43,9 @@ class Substitutions(object):
         cls.dynamic_sources.append(klass)
     register_dynamic_source = classmethod(register_dynamic_source)
 
+    def reset(self):
+        self.sources = []
+
     def feed(self, source):
         if source is None:
             # silently ignore a None source, this is for example useful when