rigor-statesman

Validates transition_to(:state) calls against the states declared in a state_machine do … end block, within the same file. A transition to an undeclared state is flagged (with a did-you-mean suggestion). It reads source only — no Statesman runtime dependency. (The DSL method names are configurable, so it also fits AASM-shaped state machines.)

It ships bundled in rigortype. Activate it under plugins::

plugins:
  - rigor-statesman

What it checks

class Order
  state_machine do
    state :draft, initial: true
    state :submitted
    state :approved
  end
end

order.transition_to(:submitted)   # info:  known state
order.transition_to(:approval)    # error: unknown state :approval (did you mean :approved?)
order.transition_to(:purgatory)   # error: unknown state :purgatory

Rule	Severity	Fires when
plugin.statesman.known-state	info	transition_to(:sym) where :sym is declared in an in-file state_machine block
plugin.statesman.unknown-state	error	transition_to(:sym) where :sym is not declared (with a Base.suggest did-you-mean)

Multiple state_machine blocks in one file union their states. Non-literal-symbol arguments and files with no state machine are silently passed through.

Configuration

plugins:
  - gem: rigor-statesman
    config:
      dsl_method: "state_machine"     # default; the block-opening method
      state_method: "state"           # default; the state-declaring method
      transition_method: "transition_to"  # default; the call to validate

Renaming these adapts the plugin to a different state-machine DSL (e.g. AASM’s aasm do … state … end).

Limitations

• File-scoped. States declared in models/order.rb aren’t visible from another file — each file validates independently.
• Literal symbols only. A variable or method-call argument is not checked.
• Receiver-agnostic. The check fires on any receiver as long as some state machine in the file declares the symbol; it does not tie a transition_to to a specific machine.

Plugin internals

rigor-statesman is the reference example for the two-pass (collect-then-validate) pattern: a node_file_context pass collects the declared states once, and a node_rule validates each transition_to over the engine-owned walk. The layout, demo, and contract surfaces are in the plugin’s README. To write a plugin, see examples/ and the rigor-plugin-author skill.