Prevent re-adding extended model elements in nexus handlers (#3486)

synapse/cortex.py

@@ -3163,6 +3163,10 @@ async def addUnivProp(self, name, tdef, info):
 
     @s_nexus.Pusher.onPush('model:univ:add')
     async def _addUnivProp(self, name, tdef, info):
+        base = '.' + name
+        if base in self.model.props:
+            return
+
         self.model.addUnivProp(name, tdef, info)
 
         await self.extunivs.set(name, (name, tdef, info))
@@ -3191,6 +3195,8 @@ async def addForm(self, formname, basetype, typeopts, typeinfo):
 
     @s_nexus.Pusher.onPush('model:form:add')
     async def _addForm(self, formname, basetype, typeopts, typeinfo):
+        if self.model.form(formname) is not None:
+            return
 
         ifaces = typeinfo.get('interfaces')
 
@@ -3224,6 +3230,8 @@ async def delForm(self, formname):
 
     @s_nexus.Pusher.onPush('model:form:del')
     async def _delForm(self, formname):
+        if self.model.form(formname) is None:
+            return
 
         for layr in self.layers.values():
             async for item in layr.iterFormRows(formname):
@@ -3259,6 +3267,9 @@ async def addFormProp(self, form, prop, tdef, info):
 
     @s_nexus.Pusher.onPush('model:prop:add')
     async def _addFormProp(self, form, prop, tdef, info):
+        if (_form := self.model.form(form)) is not None and _form.prop(prop) is not None:
+            return
+
         _prop = self.model.addFormProp(form, prop, tdef, info)
         if _prop.type.deprecated:
             mesg = f'The extended property {_prop.full} is using a deprecated type {_prop.type.name} which will' \