BB.Error.State.StaleEpoch exception (bb v0.31.2)

Command refused because it does not belong to the current arming session.

BB.Safety.armed?/1 answers "is the robot armed now?", which is not the same question as "has the robot been armed continuously since this command was created?". Without the second answer a command created during one arming session could still be applied during a later one, after an intervening disarm that was supposed to make the robot safe.

So BB.Actuator's send functions stamp each outgoing command with the arm epoch current at the moment it is sent, and BB.Actuator.Server refuses it if the robot has since moved on. A command carrying no epoch at all is refused here too: an unstamped command cannot be shown to belong to the session that is running, and hand-built commands delivered straight to an actuator are exactly the case the epoch exists to catch.

This is a :state error rather than a :safety one: the safety system working as intended is not a safety violation.

Summary

Types

t()

Functions

exception(args)

Create an Elixir.BB.Error.State.StaleEpoch without raising it.

Types

t()

@type t() :: %BB.Error.State.StaleEpoch{
  __exception__: term(),
  actuator: atom(),
  bread_crumbs: term(),
  class: term(),
  command: module(),
  current_epoch: pos_integer() | nil,
  epoch: pos_integer() | nil,
  path: term(),
  robot: module() | nil,
  splode: term(),
  stacktrace: term(),
  vars: term()
}

Functions

exception(args)

@spec exception(opts :: Keyword.t()) :: %BB.Error.State.StaleEpoch{
  __exception__: term(),
  actuator: term(),
  bread_crumbs: term(),
  class: term(),
  command: term(),
  current_epoch: term(),
  epoch: term(),
  path: term(),
  robot: term(),
  splode: term(),
  stacktrace: term(),
  vars: term()
}

Create an Elixir.BB.Error.State.StaleEpoch without raising it.

Keys

:robot
:actuator
:command
:epoch
:current_epoch