eb6a42c set HEADLESS-1 from SUNSHINE_CLIENT_WIDTH/HEIGHT/FPS but never
actually ran: Sunshine execs a prep-cmd directly, with no shell, so ${...}
was passed through literally. swaymsg received "mode ${SUNSHINE_CLIENT_WIDTH}
x..." as its argument, exited 2, and Sunshine reports any failed prep-cmd to
the client as the one opaque "failed to start the specified application".
The variable names were right and Sunshine does export them; the shell was
the missing part, which is why upstream's own example wraps the command.
Verified live at 2560x1440@60 and 1920x1080@120.
Worth keeping for the next time this breaks: swaymsg exits 2 when the socket
is reachable and the command is rejected, and 1 when it cannot find the
socket at all. That distinction is what ruled out a SWAYSOCK problem and
confirmed the malformed mode string without guessing.
connor
79da785ed4