Fix broken __eq__ implementation of Netbox stub class

changelog.d/3225.fixed.md

@@ -0,0 +1 @@
+Fix spurious crashing when loading some Netmap layer 3 views

python/nav/netmap/stubs/__init__.py

@@ -36,10 +36,8 @@ def __repr__(self):
     def __key(self):
         return self.sysname
 
-    # Yes we know we access private variable
-    # pylint: disable=W0212
-    def __eq__(self, i):
-        return self.__key() == i.__key()
+    def __eq__(self, value):
+        return self.sysname == getattr(value, "sysname", None)
 
     def __hash__(self):
         return hash(self.__key())

tests/unittests/netmap/stubs_test.py

@@ -0,0 +1,18 @@
+from nav.netmap.stubs import Netbox
+from nav.models import manage
+
+
+class TestNetboxEqWithNonStubValues:
+    def test_when_value_is_orm_model_with_same_sysname_it_should_return_true(self):
+        localhost = manage.Netbox(sysname='localhost')
+        stub = Netbox()
+        stub.sysname = localhost.sysname
+        assert stub == localhost
+
+    def test_when_value_is_orm_model_with_different_sysname_it_should_return_false(
+        self,
+    ):
+        localhost = manage.Netbox(sysname='localhost')
+        stub = Netbox()
+        stub.sysname = "stubhost"
+        assert stub != localhost