A printer card has one Power row: a plug name, its draw, and the auto-off
and on/off buttons. Which plug filled it was decided by nothing -- the
endpoint returned the first row the database handed back that was not a
Home Assistant script, from a query with no ORDER BY.
For the reporter that was an enclosure exhaust fan, added before the
outlet their X1C is plugged into. The card showed the fan's name with
'--' for watts, offered to switch the printer off by cutting the fan,
and demoted the metered outlet to the small HA button row. The fan was
marked as not powering the printer and hidden from the card; neither
setting was consulted here, though controls_printer_power has decided
the scheduler's power-on pick since #2629.
Rank the candidates instead: switchable at all, controls_printer_power,
enabled, show_on_printer_card, reports power, lowest id. The first rules
out a script, which can only be run, and an MQTT plug, which the control
endpoint rejects as monitor-only -- and an MQTT plug is exactly the kind
that reports watts, so without it ahead of the power tiebreak the row
could land on a plug whose on/off button answers with an error. The last
is not cosmetic: with no ORDER BY, a plain UPDATE on PostgreSQL can move
a row and silently swap which plug the card calls the printer's power.
None of these excludes a plug. A printer whose only plug is hidden,
disabled or monitor-only still needs its Power row, because that row
holds the on/off button and the HA buttons are drawn inside it.
controls_printer_power sits above show_on_printer_card because the two
only disagree when the plug that really feeds the printer is hidden, and
letting a display preference win there points the power buttons at an
accessory -- the fault #2629 fixed. Power capability is read from the
configuration, not measured: this runs on every card render, and it is
approximate both ways, so it only breaks a tie.
The scripts endpoint shares the same pick and excludes it, so a
switchable main plug is not repeated as a button directly below itself.
A script is left in place: a printer whose only entities are scripts
falls back to showing one in the power row, and taking it out of the
button row too would cost it the one-click run it has always had.
