View Source Bond.InvariantError exception (Bond v1.9.0)

Exception raised when an invariant is violated.

Covers all three invariant flavours, distinguished by the :kind field:

  • a struct @invariant (:kind :invariant) — checked when a public function in the struct's defining module receives or returns a value of the struct (:function is that function);
  • a Bond.Server @state_invariant (:kind :state_invariant) — checked after every state-transition callback returns a new state (:function is that callback);
  • a Bond.Server @transition_invariant (:kind :transition_invariant) — checked across every transition callback, relating old_state to new_state (:function is that callback).

Summary

Types

t()

The Bond.InvariantError exception type.

Types

Link to this type

t()

View Source 
@type t() :: %Bond.InvariantError{
  __exception__: term(),
  binding: keyword(),
  expression: Bond.assertion_expression(),
  file: Path.t(),
  function: {String.t(), non_neg_integer()},
  impl: module() | nil,
  kind: atom(),
  label: Bond.assertion_label(),
  line: integer(),
  module: module(),
  quantifier: map() | nil,
  source_behaviour: module() | nil,
  source_contract: {module(), atom()} | nil,
  source_protocol: module() | nil
}

The Bond.InvariantError exception type.

:kind is the assertion kind (:precondition, :postcondition, :invariant, :state_invariant, :transition_invariant, or :check). For Bond.InvariantError it distinguishes a struct @invariant from a Bond.Server @state_invariant / @transition_invariant; for the others it is redundant with the struct type.

:source_behaviour is the behaviour module an inherited contract came from (see Bond.Behaviour), or nil for a contract declared directly on the function.

:source_contract is the {module, name} of an applied named contract the failing assertion came from (see defcontract/@apply_contract), or nil otherwise.

:source_protocol is the protocol module a contract was declared on (see Bond.Protocol), or nil; when set, :impl is the implementation module the failing call resolved to (or nil if none could be resolved).

:quantifier carries element-level failure detail when the assertion used forall/exists (see Bond.Predicates), or nil otherwise.