When 2 extruders are defined in the Octoprint profile the Octoprint slicer will default to use both extruders even if we send an override to only use one extruder. This is a bug because Octoprint has no idea what material is in extruder 2 and can cause the printer to malfunction.
Their reasoning is this:
# NOTE: We can assume an extruder count of 1 here since the only way we currently
# support dual extrusion in this implementation is by using the second extruder for support (which
# the engine conversion will automatically detect and adapt accordingly).
#
# We currently do only support STL files as sliceables, which by default can only contain one mesh,
# so no risk of having to slice multi-objects at the moment, which would necessitate a full analysis
# of the objects to slice to determine amount of needed extruders to use here. If we ever decide to
# also support dual extrusion slicing (including composition from multiple STLs or support for OBJ or
# AMF files and the like), this code needs to be adapted!
#
# The extruder count is needed to decide which start/end gcode will be used from the Cura profile.
# Stock Cura implementation counts the number of objects in the scene for this (and also takes a look
# at the support usage, like the engine conversion here does). We only ever have one object.
However the overrides should override any action that Octoprint wants to take.
When 2 extruders are defined in the Octoprint profile the Octoprint slicer will default to use both extruders even if we send an override to only use one extruder. This is a bug because Octoprint has no idea what material is in extruder 2 and can cause the printer to malfunction.
Their reasoning is this:
However the overrides should override any action that Octoprint wants to take.