Fixes #21653: Fix multi-position tracing in CablePath.from_origin() #142

New Issue

MrUnknownDE · 2026-04-05T16:22:13+02:00

MrUnknownDE commented

2026-04-05 16:22:13 +02:00

Originally created by @jsenecal on 3/16/2026

Fixes: #21653

Summary

Fix CablePath.from_origin() to correctly trace cables when a termination has multiple positions, instead of only tracing the first position and discarding the rest
The position stack now preserves all positions from terminations[0].cable_positions and iterates over each when resolving peer terminations through cable profiles
Fix multi-connector tracing for trunk cables: stacked positions are now distributed to their owning terminations instead of always using terminations[0]
Add test coverage for multi-position and multi-connector cable path tracing scenarios

Bug 1: Multi-position loss

When a PathEndpoint had multiple cable positions (e.g. [1, 2, 3, 4]), the original code only pushed the first position onto the stack (cable_positions[0]) and only called get_peer_termination() once. This meant multi-position cables were incorrectly traced, losing position information along the path.

Bug 2: Multi-connector loss

When multiple terminations existed on different connectors of the same profiled cable (e.g. after a FrontPort fans out via PortMapping to two RearPorts on a Trunk2C2P), get_peer_termination() was only called with terminations[0]. Terminations on other connectors were dropped. See https://github.com/netbox-community/netbox/issues/21653#issuecomment-4069303962 for details.

Fix

Three changes in netbox/dcim/models/cables.py (steps from pre-existing comments):

Step 1: push all positions onto the stack (list(terminations[0].cable_positions)) instead of just the first
Step 6: build (termination, position) pairs by matching stacked positions to each termination's cable_positions, then call get_peer_termination() for each pair
Step 6 fallback: preserve legacy behavior when positions don't match any cable_positions (e.g. empty position stack)

Tests

Added test_107: duplex interface through profiled cables and splice pass-throughs (1C2P)
Added test_108: positions seeded by PortMapping preserved across profiled cables
Added test_109: 4-position interface fanning out through patch panel to both connectors of a Trunk2C2P
Ran full cable path test suite: NETBOX_CONFIGURATION=netbox.configuration_testing python manage.py test dcim.tests.test_cablepaths dcim.tests.test_cablepaths2
All existing cable path tests pass with no regressions

*Originally created by @jsenecal on 3/16/2026* ### Fixes: #21653 **Summary** - Fix CablePath.from_origin() to correctly trace cables when a termination has multiple positions, instead of only tracing the first position and discarding the rest - The position stack now preserves all positions from terminations[0].cable_positions and iterates over each when resolving peer terminations through cable profiles - Fix multi-connector tracing for trunk cables: stacked positions are now distributed to their owning terminations instead of always using terminations[0] - Add test coverage for multi-position and multi-connector cable path tracing scenarios **Bug 1: Multi-position loss** When a PathEndpoint had multiple cable positions (e.g. [1, 2, 3, 4]), the original code only pushed the first position onto the stack (cable_positions[0]) and only called get_peer_termination() once. This meant multi-position cables were incorrectly traced, losing position information along the path. **Bug 2: Multi-connector loss** When multiple terminations existed on different connectors of the same profiled cable (e.g. after a FrontPort fans out via PortMapping to two RearPorts on a Trunk2C2P), get_peer_termination() was only called with terminations[0]. Terminations on other connectors were dropped. See https://github.com/netbox-community/netbox/issues/21653#issuecomment-4069303962 for details. **Fix** Three changes in netbox/dcim/models/cables.py (steps from pre-existing comments): 1. Step 1: push all positions onto the stack (list(terminations[0].cable_positions)) instead of just the first 2. Step 6: build (termination, position) pairs by matching stacked positions to each termination's cable_positions, then call get_peer_termination() for each pair 3. Step 6 fallback: preserve legacy behavior when positions don't match any cable_positions (e.g. empty position stack) **Tests** - Added test_107: duplex interface through profiled cables and splice pass-throughs (1C2P) - Added test_108: positions seeded by PortMapping preserved across profiled cables - Added test_109: 4-position interface fanning out through patch panel to both connectors of a Trunk2C2P - Ran full cable path test suite: NETBOX_CONFIGURATION=netbox.configuration_testing python manage.py test dcim.tests.test_cablepaths dcim.tests.test_cablepaths2 - All existing cable path tests pass with no regressions

MrUnknownDE closed this issue

2026-04-05 16:22:13 +02:00

Sign in to join this conversation.

Branches Tags

main

21455-sql-indexes-audit

21357-register-model-actions

feature

20924-plugin-ui-components

21766-improve-test-coverage-for-sortable-table-columns

21157-export-template-public-models

21025-pre-render-config-contexts

21364-swagger

feature-ip-prefix-link

20911-dropdown-3

fix_module_substitution

21160-filterset

20911-dropdown-2

20044-elevation-stuck-lightmode

7604-filter-modifiers-v3

20660-script-load

19724-graphql

14884-script

19720-macaddress-interface-generic-relation

fix-19669-api-image-download

7604-filter-modifiers

19275-fixes-interface-bulk-edit

fix-17794-get_field_value_return_list

11507-show-aggregate-and-rir-on-api

9583-add_column_specific_search_field_to_tables

No Label

1 Participants

Notifications

Due Date

No due date set.

Dependencies

No dependencies set.

Reference: github/netbox#142

Fixes #21653: Fix multi-position tracing in CablePath.from_origin() #142

Fixes: #21653

Fixes #21653: Fix multi-position tracing in `CablePath.from_origin()` #142