Some community-generated KiCad symbol libraries (e.g.
PCM_Diode_Schottky_AKL:MBRS130) define each pin number twice — once as a
visible "real" pin with non-zero length whose ``at`` coordinate is the
wire-connection endpoint, and once as an inner zero-length "ghost" pin
used as an internal graphic-anchoring join. Both definitions live inside
the same ``lib_symbols`` block.
``parse_symbol_definition`` stored pins via ``pins[number] = pin_data``
— a plain assignment. Each duplicate-numbered pin encountered during the
recursive walk overwrote the previous one. The recursion order put the
ghost pins last for MBRS130, so the ghost won and ``get_pin_location``
returned a coordinate that did not match any wire/label.
Downstream this caused ``get_connections_for_net`` to silently miss diode
pins on the rails they were wired to — on a real schematic, querying
``+BATT`` returned 8 of 9 expected nodes (D1/1 absent) and ``+3V3``
returned 44 of 46 (D1/2 and D2/2 absent), because the BFS could not find
the diode's pin endpoint at the labelled position.
Fix: when the same pin number is defined more than once, keep the entry
with the greater ``length``. The outer real pin has length > 0; the
inner ghost has length == 0. Strict-greater comparison resolves ties to
first-encountered, so legitimate same-length duplicates (e.g., per-unit
repetitions in multi-unit symbols) keep stable existing behaviour.
Tests: four unit tests in ``tests/test_pin_locator_duplicate_pin_defs.py``
cover (a) outer-then-ghost order (the real bug), (b) ghost-then-outer
order (length-not-order heuristic), (c) no-duplicate baseline regression,
and (d) equal-length tie keeps first-encountered. Two of the four fail
on main, all four pass on this branch.
Full suite: 671 passed, 11 skipped, 0 regressions (modulo the pre-existing
tests/test_get_pin_angle.py collection error which is unrelated to
pin_locator).
End-to-end on the real schematic that triggered the report: after the
fix ``get_connections_for_net('+BATT')`` returns all 9 expected nodes
matching ``kicad-cli sch export netlist`` exactly. The companion fix in
PR #177 (wire_connectivity pwr-flag bridge) closes the orthogonal
over-merge bug; together they bring net membership to full parity with
kicad-cli on schematics that use both ``PWR_FLAG`` markers and
diodes from community libraries.
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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