fix(api): replace invoice lines in a single transaction

packages/api/src/routes/invoices.test.ts

@@ -1,9 +1,9 @@
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 import { createApp } from "../app.js";
 import { createMemoryDocumentsStore } from "../documents.js";
 import { loadEnv } from "../env.js";
 import type { ErrorEnvelope } from "../http.js";
-import { createFakeDb, SEED } from "../test/fake-db.js";
+import { createFakeDb, emptyStore, SEED } from "../test/fake-db.js";
 
 function expectEnvelope(body: unknown, code: string) {
   const envelope = body as ErrorEnvelope;
@@ -114,6 +114,35 @@ describe("invoice stubs", () => {
     expect(body.items).toHaveLength(2);
   });
 
+  it("keeps existing lines when a replace insert fails", async () => {
+    const store = emptyStore();
+    const handle = createFakeDb(store);
+    const db = handle.db as { insert: ReturnType<typeof vi.fn> };
+    db.insert.mockImplementation(() => ({
+      values: () => ({
+        returning: async () => {
+          throw new Error("insert failed");
+        },
+      }),
+    }));
+    const app = createApp(envFor("admin"), handle, {
+      documents: createMemoryDocumentsStore(),
+    });
+    const response = await app.request(`/api/invoices/${SEED.invoice.id}/lines`, {
+      method: "PUT",
+      headers: jsonHeaders,
+      body: JSON.stringify({
+        items: [
+          { description: "Labor", amount: "1000.00" },
+          { description: "Parts", amount: "250.00" },
+        ],
+      }),
+    });
+    expect(response.status).toBe(500);
+    expect(store.invoiceLines).toHaveLength(1);
+    expect(store.invoiceLines[0]?.id).toBe(SEED.line.id);
+  });
+
   it("presigns a document and confirms after upload", async () => {
     const documents = createMemoryDocumentsStore();
     const app = createApp(envFor("admin"), createFakeDb(), { documents });

packages/api/src/routes/invoices.ts

@@ -379,15 +379,17 @@ export function createInvoiceRoutes(handle: Db, store: DocumentsStore) {
     if (!linesSumToAmount(parsedLines, invoice.amount)) {
       return errorJson(c, 400, "VALIDATION_ERROR", "Line amounts must sum to the invoice amount.");
     }
-    await handle.db.delete(invoiceLines).where(eq(invoiceLines.invoiceId, id));
     const created: LineRow[] = [];
-    for (const line of parsedLines) {
-      const [row] = await handle.db
-        .insert(invoiceLines)
-        .values({ invoiceId: id, ...line })
-        .returning();
-      created.push(row);
-    }
+    await handle.db.transaction(async (tx) => {
+      await tx.delete(invoiceLines).where(eq(invoiceLines.invoiceId, id));
+      for (const line of parsedLines) {
+        const [row] = await tx
+          .insert(invoiceLines)
+          .values({ invoiceId: id, ...line })
+          .returning();
+        created.push(row);
+      }
+    });
     return c.json({ items: created.map(toLine) });
   });
 

packages/api/src/test/fake-db.ts

@@ -233,6 +233,22 @@ export function createFakeDb(store: Store = emptyStore()): Db {
         rows.splice(0, rows.length);
       }),
     })),
+    transaction: vi.fn(async (callback: (tx: never) => Promise<unknown>) => {
+      const snapshot = structuredClone(store) as Store;
+      try {
+        return await callback(db as never);
+      } catch (error) {
+        (Object.keys(store) as Array<keyof Store>).forEach((key) => {
+          const rows = store[key] as unknown as Array<Record<string, unknown>>;
+          rows.splice(
+            0,
+            rows.length,
+            ...(snapshot[key] as unknown as Array<Record<string, unknown>>),
+          );
+        });
+        throw error;
+      }
+    }),
   };
 
   return {