In this PR, we enable extensions to track changes in the current prefs. These changes can result from a profile switch
or from the user or system modifying the current profile’s prefs. Since some extensions may want to distinguish between
the two events, while others may treat them similarly, we rename the existing profile-change callback to become
a profile-state-change callback and invoke it whenever the current profile or its preferences change. Extensions can still
use the sameNode parameter to distinguish between situations where the profile information, including its preferences,
has been updated but still represents the same tailnet node, and situations where a switch to a different profile has been made.
Having dedicated prefs-change callbacks is being considered, but currently seems redundant. A single profile-state-change callback
is easier to maintain. We’ll revisit the idea of adding a separate callback as we progress on extracting existing features from LocalBackend,
but the conversion to a profile-state-change callback is intended to be permanent.
Finally, we let extensions retrieve the current prefs or profile state (profile info + prefs) at any time using the new
CurrentProfileState and CurrentPrefs methods. We also simplify the NewControlClientCallback signature to exclude
profile prefs. It’s optional, and extensions can retrieve the current prefs themselves if needed.
Updates #12614
Updates tailscale/corp#27645
Updates tailscale/corp#26435
Updates tailscale/corp#27502
Signed-off-by: Nick Khyl <nickk@tailscale.com>
Nick Khyl
e6eba4efee