The pre-print deficit warning from #720 only ran inside the PrintModal
submit flow. Both the green ▶ button on a staged queue row (POST
/queue/{id}/start) and the Virtual Printer queue-mode intake bypassed
it — auto_dispatch=True VP intakes would dispatch unsupervised onto
spools that physically can't complete the print.
Extracted the deficit check into backend/app/services/filament_deficit.py
(single source of truth, both internal inventory and Spoolman modes).
POST /queue/{id}/start returns 409 with a structured deficit payload
unless ?skip_filament_check=true. The dispatch scheduler runs the same
check before each _start_print; a deficit promotes the item to
manual_start + sets a new filament_short flag (idempotent migration on
print_queue). The flag clears automatically on the next tick when the
operator swaps a spool to one with enough material.
Frontend ▶ catches the 409 and opens a confirm modal showing each
shorted slot's required vs remaining grams; the row now renders a
yellow "Insufficient filament" badge when filament_short is set.
Translated across all 9 locales.
maziggy
7ea4410b21