fix: refuse an unknown operation when reading reminders

unschedule already refused an operation the actor does not declare, but
reminder and reminders did not. A typo returned nil and an empty array,
so a caller asking whether an alarm was armed got told no rather than
told it had asked the wrong question. Both now raise the UnknownMessage
that schedule and unschedule raise.

Found by auditing the Ruby and JavaScript surfaces against each other:
the JavaScript reader already validated, and this side did not.

Author: cardmagic

CHANGELOG.md

@@ -2,7 +2,8 @@
 
 ## Unreleased
 
-- Refuse an unknown operation in `unschedule` and `unschedule_all`. `schedule`
+- Refuse an unknown operation in `reminder`, `reminders`, `unschedule`, and
+  `unschedule_all`. `schedule`
   already raised `UnknownMessage` for one, so a typo cancelled nothing quietly
   and left a recurring reminder running.
 - Add reminder cancellation. `unschedule` removes one reminder by operation and

lib/solid_objects/actor.rb

@@ -293,12 +293,13 @@ def unschedule_all(operation)
     def reminder(operation_or_handle, key: nil)
       return reminder_view[handle_name(operation_or_handle, key:)] if operation_or_handle.is_a?(Hash)
 
+      validated_reminder_operation(operation_or_handle)
       reminder_view[reminder_name(operation: operation_or_handle, key: validated_reminder_key(key))]
     end
 
     # @rbs (Symbol | String) -> Array[ReminderStatus]
     def reminders(operation)
-      wanted = operation.to_s
+      wanted = validated_reminder_operation(operation)
       reminder_view.each_value.select { |status| status.operation == wanted }
     end
 

test/integration/reminder_cancellation_test.rb

@@ -38,6 +38,14 @@ def convert_then_raise
       raise "turn failed"
     end
 
+    def read_unknown
+      reminder(:no_such_operation)
+    end
+
+    def list_unknown
+      reminders(:no_such_operation)
+    end
+
     def cancel_unknown
       unschedule(:no_such_operation)
     end
@@ -283,6 +291,20 @@ def state_of(actor_type)
     assert_empty reminders_for("cancel-trial")
   end
 
+  test "an unknown operation is refused when reading rather than reported absent" do
+    SolidObjects.configuration.max_attempts = 1
+    reference = TrialActor.ref("alice")
+    reference.async.start_trial
+    drain
+    reference.async.read_unknown
+    reference.async.list_unknown
+    drain
+
+    assert_equal 2, SolidObjects::DeadLetter.where(actor_type: "cancel-trial").count
+    assert_equal [ "SolidObjects::UnknownMessage" ],
+      SolidObjects::DeadLetter.where(actor_type: "cancel-trial").distinct.pluck(:exception_class)
+  end
+
   test "an unknown operation is refused rather than cancelling nothing" do
     SolidObjects.configuration.max_attempts = 1
     reference = TrialActor.ref("alice")