refactor: check persisted json payload shape instead of double casts (#152) (#154)

src/modules/investments/portfolio/infrastructure/portfolio.repository.ts

@@ -200,3 +200,16 @@ export class PortfolioRepository {
 export function portfolioWorkKey(accountId: string): string {
   return `portfolio:${JSON.stringify(accountId)}`;
 }
+
+// Json payload is written only by publish(); a shape check turns corruption into an explicit 500.
+export function portfolioSnapshot(value: Prisma.JsonValue): PortfolioDto {
+  const snapshot = value as null | Partial<PortfolioDto>;
+  if (
+    !Array.isArray(snapshot?.positions) ||
+    !Array.isArray(snapshot.totalsByCurrency) ||
+    !Array.isArray(snapshot.cashBalances)
+  ) {
+    throw new Error('Corrupted portfolio snapshot payload');
+  }
+  return snapshot as PortfolioDto;
+}