Report a Semi-Final slot that was emptied without being refilled

The re-seed banner listed only the slots that were filled, so a re-seed that
just vacated one — un-recording an Elimination Final result takes its winner
back out of the semi — rendered as "Re-seeded the Semi-Finals: ." with nothing
after the colon.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MSDeNWAXvK7nznJqjxn7Jo

app/routes/__tests__/admin.sports-seasons.bracket.reseed-afl-semifinals.test.ts

@@ -87,6 +87,20 @@ describe("reseed-afl-semifinals", () => {
     });
   });
 
+  it("reports a slot that was emptied without being refilled", async () => {
+    // Un-recording an Elimination Final result takes its winner back out of the semi.
+    vi.mocked(reseedAflSemiFinals).mockResolvedValue({
+      vacated: [1, 2],
+      filled: [{ matchNumber: 2, participantId: "adelaide" }],
+    });
+
+    expect(await run()).toEqual({
+      success:
+        "Re-seeded the Semi-Finals: match 1 is back to TBD, " +
+        "match 2 now hosts Adelaide Crows.",
+    });
+  });
+
   it("says so when the pairings are already right", async () => {
     vi.mocked(reseedAflSemiFinals).mockResolvedValue({ vacated: [], filled: [] });
 

app/routes/admin.sports-seasons.$id.events.$eventId.bracket.server.ts

@@ -935,9 +935,20 @@ export async function action({ request, params }: Route.ActionArgs) {
 
       // Only the qualifier slots move, so there is nothing to re-score: no placement,
       // score or elimination changes, and so nothing to announce.
-      const moves = reseed.filled
+      //
+      // A slot can be vacated without being refilled — un-recording an Elimination Final
+      // result takes its winner back out — so report those too rather than rendering an
+      // empty list.
+      const filled = reseed.filled.map((slot) => ({
+        matchNumber: slot.matchNumber,
+        text: `match ${slot.matchNumber} now hosts ${nameOf(slot.participantId)}`,
+      }));
+      const emptied = reseed.vacated
+        .filter((matchNumber) => !reseed.filled.some((slot) => slot.matchNumber === matchNumber))
+        .map((matchNumber) => ({ matchNumber, text: `match ${matchNumber} is back to TBD` }));
+      const moves = [...filled, ...emptied]
         .toSorted((a, b) => a.matchNumber - b.matchNumber)
-        .map((slot) => `match ${slot.matchNumber} now hosts ${nameOf(slot.participantId)}`)
+        .map((move) => move.text)
         .join(", ");
 
       return {