fix(multiplayer): repair allocated compose verification

server/store/match_sql.go

@@ -81,9 +81,14 @@ func PromoteStoredAcceptedProposal(ctx context.Context, db *sql.DB, proposalID s
 		return fmt.Errorf("invalid stored proposal promotion arguments")
 	}
 	plan := AcceptedMatchPlan{MatchID: "match-" + proposalID, ProposalID: proposalID}
-	if err := db.QueryRowContext(ctx, StoredProposalMatchPlanSQL, proposalID).Scan(&plan.Region, &plan.Protocol, &plan.ArenaPath); err != nil {
+	// Casual proposals intentionally persist no arena path. Scan it as nullable
+	// here just as the in-transaction promotion path does, so an API retry after
+	// the atomic promotion does not turn a successful acceptance into a 503.
+	var arenaPath sql.NullString
+	if err := db.QueryRowContext(ctx, StoredProposalMatchPlanSQL, proposalID).Scan(&plan.Region, &plan.Protocol, &arenaPath); err != nil {
 		return err
 	}
+	plan.ArenaPath = arenaPath.String
 	rows, err := db.QueryContext(ctx, StoredProposalMatchPlayersSQL, proposalID)
 	if err != nil {
 		return err

server/store/postgres_integration_test.go

@@ -778,6 +778,12 @@ func TestPostgreSQLProposalClaimAndResponseAreAtomic(t *testing.T) {
 	if accepted.State != domain.Accepted || accepted.Revision != 2 {
 		t.Fatalf("proposal did not close after unanimous acceptance: %+v", accepted)
 	}
+	// The API's post-commit recovery promoter must accept the nullable casual
+	// arena path left by the atomic response transaction and converge on the
+	// already-created match.
+	if err := PromoteStoredAcceptedProposal(ctx, db, proposal.ProposalID, now.Add(time.Second)); err != nil {
+		t.Fatalf("replay persisted casual promotion: %v", err)
+	}
 	var matchState string
 	if err := db.QueryRow(`SELECT state FROM matches WHERE match_id = 'match-proposal-integration'`).Scan(&matchState); err != nil {
 		t.Fatalf("atomic accepted match: %v", err)