fix: do not report a spent reminder as armed

A one-shot keeps its row after it fires, as completed, and the view
returned it. A next-run lookup reported an old time rather than nothing,
and an existence check refused to re-arm an alarm that could never fire
again.

Found by auditing against the JavaScript port, where the same defect was
reported. Both sides drop completed rows now.

Author: cardmagic

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+- Leave a one-shot reminder that already fired out of `reminder` and
+  `reminders`. Its row stays as `completed`, so a next-run lookup reported an
+  old time rather than nothing, and an existence check refused to re-arm an
+  alarm that could never fire again.
 - Refuse an unknown operation in `reminder`, `reminders`, `unschedule`, and
   `unschedule_all`. `schedule`
   already raised `UnknownMessage` for one, so a typo cancelled nothing quietly

lib/solid_objects/actor.rb

@@ -344,7 +344,7 @@ def reminder_view
     def committed_reminders
       return {} unless instance_id
 
-      Reminder.where(instance_id:).each_with_object({}) do |row, view|
+      Reminder.where(instance_id:).where.not(status: "completed").each_with_object({}) do |row, view|
         view[row.name] = reminder_status(
           name: row.name,
           operation: row.operation,

test/integration/reminder_cancellation_test.rb

@@ -137,6 +137,14 @@ def arm
       schedule(at: Time.utc(2030, 1, 1), every: 90).ping
     end
 
+    def arm_due
+      schedule(at: 1.second.ago).ping
+    end
+
+    def read_name
+      self.seen = { "name" => reminder(:ping)&.name }
+    end
+
     def read_next_run
       found = reminder(:ping)
       self.seen = found && {
@@ -412,6 +420,26 @@ def state_of(actor_type)
     scheduler&.stop
   end
 
+  test "inspection does not report a one-shot that already fired" do
+    reference = InspectorActor.ref("one")
+    reference.async.arm_due
+    drain
+    reference.async.read_name
+    drain
+
+    assert_equal "ping", state_of("cancel-inspector").fetch("seen").fetch("name")
+
+    scheduler = SolidObjects::ReminderScheduler.new
+    scheduler.run_once
+    drain
+    reference.async.read_name
+    drain
+
+    assert_nil state_of("cancel-inspector").fetch("seen").fetch("name")
+  ensure
+    scheduler&.stop
+  end
+
   test "inspection reports the next run time and interval" do
     reference = InspectorActor.ref("one")
     reference.async.arm