The LocalBackend's state machine starts in NoState and soon transitions to NeedsLogin if there's no auto-start profile,
with the profileManager starting with a new empty profile. Notably, entering the NeedsLogin state blocks engine updates.
We expect the user to transition out of this state by logging in interactively, and we set WantRunning to true when
controlclient enters the StateAuthenticated state.
While our intention is correct, and completing an interactive login should set WantRunning to true, our assumption
that logging into the current Tailscale profile is the only way to transition out of the NeedsLogin state is not accurate.
Another common transition path includes an explicit profile switch (via LocalBackend.SwitchProfile) or an implicit switch
when a Windows user connects to the backend. This results in a bug where WantRunning is set to true even when it was
previously set to false, and the user expressed no intention of changing it.
A similar issue occurs when switching from (sic) a Tailnet that has seamlessRenewalEnabled, regardless of the current state
of the LocalBackend's state machine, and also results in unexpectedly set WantRunning. While this behavior is generally
undesired, it is also incorrect that it depends on the control knobs of the Tailnet we're switching from rather than
the Tailnet we're switching to. However, this issue needs to be addressed separately.
This PR updates LocalBackend.SetControlClientStatus to only set WantRunning to true in response to an interactive login
as indicated by a non-empty authURL.
Fixes#6668Fixes#11280
Updates #12756
Signed-off-by: Nick Khyl <nickk@tailscale.com>
b48c8db69c