test: cover account snapshot metadata edges

(cherry picked from commit 51313b6)

Author: ndycode

lib/storage/account-snapshot.ts

@@ -33,7 +33,8 @@ export async function statSnapshot(
 }
 
 /**
- * Build backup metadata for an account snapshot, treating ENOENT races as missing files.
+ * Build backup metadata for an account snapshot, treating ENOENT load races as invalid snapshots
+ * that were present when the initial stat succeeded.
  */
 export async function describeAccountSnapshot(
 	path: string,
@@ -56,18 +57,26 @@ export async function describeAccountSnapshot(
 	try {
 		const { normalized, schemaErrors, storedVersion } =
 			await deps.loadAccountsFromPath(path);
-		const resolvedStats =
-			stats.bytes === undefined || stats.mtimeMs === undefined
-				? await deps.statSnapshot(path)
-				: stats;
+		let resolvedStats = stats;
+		for (
+			let attempt = 0;
+			attempt < 2 &&
+			(resolvedStats.bytes === undefined || resolvedStats.mtimeMs === undefined);
+			attempt += 1
+		) {
+			const refreshedStats = await deps.statSnapshot(path);
+			if (refreshedStats.exists) {
+				resolvedStats = refreshedStats;
+			}
+		}
 		return {
 			kind,
 			path,
 			index: deps.index,
 			exists: true,
 			valid: !!normalized,
-			bytes: resolvedStats.bytes,
-			mtimeMs: resolvedStats.mtimeMs,
+			bytes: resolvedStats.bytes ?? 0,
+			mtimeMs: resolvedStats.mtimeMs ?? 0,
 			version: typeof storedVersion === "number" ? storedVersion : undefined,
 			accountCount: normalized?.accounts.length,
 			schemaErrors: schemaErrors.length > 0 ? schemaErrors : undefined,

test/account-snapshot.test.ts

@@ -2,6 +2,15 @@ import { describe, expect, it, vi } from "vitest";
 import { describeAccountSnapshot, statSnapshot } from "../lib/storage/account-snapshot.js";
 
 describe("statSnapshot", () => {
+	it("returns size and mtime for accessible snapshots", async () => {
+		await expect(
+			statSnapshot("accounts.json", {
+				stat: vi.fn(async () => ({ size: 1234, mtimeMs: 5678 })),
+				logWarn: vi.fn(),
+			}),
+		).resolves.toEqual({ exists: true, bytes: 1234, mtimeMs: 5678 });
+	});
+
 	it("returns missing metadata for ENOENT", async () => {
 		await expect(
 			statSnapshot("missing.json", {
@@ -16,7 +25,7 @@ describe("statSnapshot", () => {
 	it("logs and returns missing metadata for non-ENOENT stat failures", async () => {
 		const logWarn = vi.fn();
 		await expect(
-			statSnapshot("locked.json", {
+			statSnapshot("denied.json", {
 				stat: vi.fn(async () => {
 					throw Object.assign(new Error("denied"), { code: "EACCES" });
 				}),
@@ -25,7 +34,7 @@ describe("statSnapshot", () => {
 		).resolves.toEqual({ exists: false });
 		expect(logWarn).toHaveBeenCalledWith(
 			"Failed to stat backup candidate",
-			expect.objectContaining({ path: "locked.json" }),
+			expect.objectContaining({ path: "denied.json" }),
 		);
 	});
 	it("treats locked snapshots as existing when stat returns EBUSY", async () => {
@@ -164,6 +173,39 @@ describe("describeAccountSnapshot", () => {
 		expect(statSnapshot).toHaveBeenCalledTimes(2);
 	});
 
+	it("falls back to zeroed metadata after repeated stat locks", async () => {
+		const statSnapshot = vi
+			.fn()
+			.mockResolvedValueOnce({ exists: true })
+			.mockResolvedValueOnce({ exists: true })
+			.mockResolvedValueOnce({ exists: true });
+
+		await expect(
+			describeAccountSnapshot("accounts.json", "accounts-primary", {
+				index: 0,
+				statSnapshot,
+				loadAccountsFromPath: vi.fn(async () => ({
+					normalized: { accounts: [{ id: 1 }] },
+					schemaErrors: [],
+					storedVersion: 3,
+				})),
+				logWarn: vi.fn(),
+			}),
+		).resolves.toEqual({
+			kind: "accounts-primary",
+			path: "accounts.json",
+			index: 0,
+			exists: true,
+			valid: true,
+			bytes: 0,
+			mtimeMs: 0,
+			version: 3,
+			accountCount: 1,
+		});
+
+		expect(statSnapshot).toHaveBeenCalledTimes(3);
+	});
+
 	it("returns invalid metadata when the loader fails", async () => {
 		const logWarn = vi.fn();
 		await expect(