Which of a plan's ops would land on a channel that is already carrying something else.
PURE, and separate from planStageboxAssign on purpose: the plan is GEOMETRY (which
port maps to which channel, bounded by the box's width and the fabric's slots) and cannot know
what the desk currently holds. This is the second question — "and is anything there?" — asked
against a live reading, so a one-tap bulk patch can say what it is about to sum onto before it
does it rather than after.
An op whose channel already holds THE SAME endpoint is not a collision: re-assigning a box to
where it already is, is the idempotent no-op the operator expects from a fast-setup button.
Which of a plan's ops would land on a channel that is already carrying something else.
PURE, and separate from planStageboxAssign on purpose: the plan is GEOMETRY (which port maps to which channel, bounded by the box's width and the fabric's slots) and cannot know what the desk currently holds. This is the second question — "and is anything there?" — asked against a live reading, so a one-tap bulk patch can say what it is about to sum onto before it does it rather than after.
An op whose channel already holds THE SAME endpoint is not a collision: re-assigning a box to where it already is, is the idempotent no-op the operator expects from a fast-setup button.