Fixes #17400: Handle cablepaths directly via multiple single-position…

… rear ports

netbox/dcim/models/cables.py

@@ -666,6 +666,14 @@ def from_origin(cls, terminations):
                         rear_port_id=remote_terminations[0].pk,
                         rear_port_position__in=position_stack.pop()
                     )
+                # If all rear ports have a single position, we can just get the front ports
+                elif all([rp.positions == 1 for rp in remote_terminations]):
+                    front_ports = FrontPort.objects.filter(rear_port_id__in=[rp.pk for rp in remote_terminations])
+
+                    if len(front_ports) != len(remote_terminations):
+                        # Some rear ports does not have a front port
+                        is_split = True
+                        break
                 else:
                     # No position indicated: path has split, so we stop at the RearPorts
                     is_split = True

netbox/dcim/tests/test_cablepaths.py

@@ -2060,6 +2060,49 @@ def test_221_non_symmetric_paths(self):
         # Test SVG generation
         CableTraceSVG(interface1).render()
 
+    def test_222_single_path_via_multiple_singleposition_rear_ports(self):
+        """
+        [IF1] --C1-- [FP1] [RP1] --C2-- [IF2]
+                     [FP2] [RP2]
+        """
+        interface1 = Interface.objects.create(device=self.device, name='Interface 1')
+        interface2 = Interface.objects.create(device=self.device, name='Interface 2')
+        rearport1 = RearPort.objects.create(device=self.device, name='Rear Port 1', positions=1)
+        rearport2 = RearPort.objects.create(device=self.device, name='Rear Port 2', positions=1)
+        frontport1 = FrontPort.objects.create(
+            device=self.device, name='Front Port 1', rear_port=rearport1, rear_port_position=1
+        )
+        frontport2 = FrontPort.objects.create(
+            device=self.device, name='Front Port 2', rear_port=rearport2, rear_port_position=1
+        )
+
+        cable1 = Cable(
+            a_terminations=[interface1],
+            b_terminations=[frontport1, frontport2]
+        )
+        cable1.save()
+        self.assertEqual(CablePath.objects.count(), 1)
+
+        cable2 = Cable(
+            a_terminations=[rearport1, rearport2],
+            b_terminations=[interface2]
+        )
+        cable2.save()
+        self.assertEqual(CablePath.objects.count(), 2)
+
+        self.assertPathExists(
+            (interface1, cable1, (frontport1, frontport2), (rearport1, rearport2), cable2, interface2),
+            is_complete=True
+        )
+        self.assertPathExists(
+            (interface2, cable2, (rearport1, rearport2), (frontport1, frontport2), cable1, interface1),
+            is_complete=True
+        )
+
+        # Test SVG generation both directions
+        CableTraceSVG(interface1).render()
+        CableTraceSVG(interface2).render()
+
     def test_301_create_path_via_existing_cable(self):
         """
         [IF1] --C1-- [FP1] [RP1] --C2-- [RP2] [FP2] --C3-- [IF2]