First-attempt fix (d196cfc5) was wrong about the cause. Real root,
traced via @mkoreen's BAMBUDDY_VP_DUMP_WIRE capture + 2026-06-21
support bundle:
mqtt_server.py:1296 was passing the slicer's bare subtask_name
(e.g. "Model_Name") into on_print_command, which stashed under
that key. _add_to_print_queue looked up under file_path.name
(the FTP filename WITH extension, "Model_Name.gcode.3mf"). The
two strings never matched. pop returned None, the 2s wait fired
against a key the stash side never signaled, every captured
slicer field silently fell back to settings defaults.
Affected EVERY Bambu Studio "Send" upload across EVERY model —
not just H2C nozzle_mapping. bed_leveling / flow_cali /
vibration_cali / layer_inspect / timelapse from the original
#1403 capture have been silently ignored since BambuStudio
started splitting subtask_name (bare) from file (with extension).
Unit tests passed because fixtures called on_print_command with
file_path.name directly, bypassing the broken caller.
Fix in manager.py::on_print_command: derive
stash_key = data.get("file") or filename and use it for both
_slicer_print_options and the event lookup. filename
(subtask_name) still flows unchanged to _schedule_finish_release
— push_status echoes it back as gcode_file / subtask_name and
the slicer matches against its own subtask_name there, so
re-routing that path was a separate regression I caught and
reverted mid-audit.
Also: nozzles_info field was a wrong guess in d196cfc5 —
BambuStudio never sends it (confirmed via wire capture). Drop
the capture, dispatch, schema, kwarg, and route paths. DB
column stays nullable so old rows still load; nothing reads
or writes it.
Diagnostic: DEBUG log when _add_to_print_queue finds no slicer
options after the 2s wait, including the looked-up key and the
actual cache keys present. Future stash/lookup mismatches will
be obvious from a log line instead of needing a wire capture.
Behaviour change worth flagging: users on Bambu Studio whose
slicer-side bed-leveling / flow-cali / vibration-cali /
layer-inspect / timelapse differ from Bambuddy's
default-workflow settings will see their slicer choices
honored now instead of silently overridden. Restores #1403's
original intent.