Function plan 

pub fn plan(
    setting: Option<bool>,
    entry: Option<&Entry>,
    channel: &str,
    target: Option<&str>,
) -> Plan

Pure decision. setting is app:startatlogin, None when never set. target is stable_target(), None when it could not be resolved: only writing needs it, so removing or adopting never waits on it (ReAgent P1 on #3788).

• On: write unless the entry already runs target for this channel. This also re-points an entry after an update or a move, and takes ownership from another channel (last enabled wins).
• Off: remove only an entry this channel owns. Another build’s entry, or one from before ownership was recorded, is not this build’s to remove.
• Never set: off, except that an unowned (pre-setting) entry is adopted.