fix: dont schedule already-scheduled runs at startup

internal/run/scheduler.go

@@ -186,7 +186,14 @@ func (q queue) process(run *Run) (qq queue, enqueuePlan bool, unlock bool) {
 				unlock = true
 			}
 		} else {
-			// check if run is in backlog
+			if q.current == nil && run.Status != RunPending && !run.Done() {
+				// This condition handles the scenario where the scheduler has
+				// only been started up and the scheduler has not yet set the
+				// current run and there is an existing scheduled run that is
+				// not yet done.
+				q.current = &run.ID
+				return q, false, false
+			}
 			var found bool
 			for i, id := range q.backlog {
 				if run.ID == id {

internal/run/scheduler_test.go

@@ -111,13 +111,21 @@ func TestScheduler_process(t *testing.T) {
 			false,
 		},
 		{
-			"make run current and request enqueue plan",
+			"make pending run current and request enqueue plan",
 			queue{},
-			&Run{ID: runID1},
+			&Run{ID: runID1, Status: RunPending},
 			queue{current: &runID1},
 			true,
 			false,
 		},
+		{
+			"make plan_enqueued run current and do not request enqueue plan",
+			queue{},
+			&Run{ID: runID1, Status: RunPlanQueued},
+			queue{current: &runID1},
+			false,
+			false,
+		},
 		{
 			"move backlogged run into current and request enqueue plan",
 			queue{backlog: []resource.ID{runID1}},