Add runtime persistence failure coverage

Author: ndycode

lib/runtime/account-check.ts

@@ -328,7 +328,7 @@ export async function runRuntimeAccountCheck(
 		deps.invalidateAccountManagerCache();
 	} else {
 		if (state.flaggedChanged) {
-		await deps.saveFlaggedAccounts(state.flaggedStorage);
+			await deps.saveFlaggedAccounts(state.flaggedStorage);
 		}
 		if (state.storageChanged) {
 			await deps.saveAccounts(workingStorage);

test/runtime-account-check.test.ts

@@ -263,6 +263,51 @@ describe("runRuntimeAccountCheck", () => {
 		expect(saveFlaggedAccounts).not.toHaveBeenCalled();
 	});
 
+	it("propagates EBUSY from combined persistence without partial writes", async () => {
+		const persistAccountAndFlaggedStorage = vi.fn(async () => {
+			const error = new Error("busy") as Error & { code?: string };
+			error.code = "EBUSY";
+			throw error;
+		});
+		const saveAccounts = vi.fn(async () => {});
+		const saveFlaggedAccounts = vi.fn(async () => {});
+
+		await expect(
+			runRuntimeAccountCheck(true, {
+				hydrateEmails: async (storage) => storage,
+				loadAccounts: async () => ({
+					version: 3,
+					accounts: [{ email: "one@example.com", refreshToken: "refresh-1", accessToken: undefined, addedAt: 1, lastUsed: 1 }],
+					activeIndex: 0,
+					activeIndexByFamily: { codex: 0 },
+				}),
+				createEmptyStorage: () => ({ version: 3, accounts: [], activeIndex: 0, activeIndexByFamily: {} }),
+				loadFlaggedAccounts: async () => ({ version: 1, accounts: [] }),
+				createAccountCheckWorkingState: (flaggedStorage) => ({ flaggedStorage, removeFromActive: new Set(), storageChanged: false, flaggedChanged: false, ok: 0, errors: 0, disabled: 0 }),
+				lookupCodexCliTokensByEmail: async () => null,
+				extractAccountId: () => undefined,
+				shouldUpdateAccountIdFromToken: () => false,
+				sanitizeEmail: (email) => email,
+				extractAccountEmail: () => undefined,
+				queuedRefresh: async () => ({ type: "failed", reason: "invalid_grant", message: "refresh failed" }),
+				isRuntimeFlaggableFailure: () => true,
+				fetchCodexQuotaSnapshot: async () => { throw new Error("should not probe quota in deep mode"); },
+				resolveRequestAccountId: () => undefined,
+				formatCodexQuotaLine: () => "quota",
+				clampRuntimeActiveIndices: vi.fn(),
+				MODEL_FAMILIES: ["codex"],
+				saveAccounts,
+				invalidateAccountManagerCache: vi.fn(),
+				saveFlaggedAccounts,
+				persistAccountAndFlaggedStorage,
+				showLine: vi.fn(),
+			}),
+		).rejects.toThrow("busy");
+
+		expect(saveAccounts).not.toHaveBeenCalled();
+		expect(saveFlaggedAccounts).not.toHaveBeenCalled();
+	});
+
 	it("treats cache lookup failures as a cache miss and still refreshes", async () => {
 		const saveAccounts = vi.fn(async () => {});
 		await runRuntimeAccountCheck(false, {

test/runtime-verify-flagged.test.ts

@@ -345,6 +345,52 @@ describe("verifyRuntimeFlaggedAccounts", () => {
 		expect(saveFlaggedAccounts).not.toHaveBeenCalled();
 	});
 
+	it("propagates EBUSY from persistAccountsAndFlagged without partial writes", async () => {
+		const now = 10_000;
+		const persistAccountsAndFlagged = vi.fn(async () => {
+			const error = new Error("busy") as Error & { code?: string };
+			error.code = "EBUSY";
+			throw error;
+		});
+		const persistAccounts = vi.fn(async () => {});
+		const saveFlaggedAccounts = vi.fn(async () => {});
+
+		await expect(
+			verifyRuntimeFlaggedAccounts({
+				loadFlaggedAccounts: async () => ({
+					version: 1,
+					accounts: [
+						{
+							email: "refresh@example.com",
+							refreshToken: "refresh-token",
+							addedAt: 1,
+							lastUsed: 1,
+						},
+					],
+				}),
+				lookupCodexCliTokensByEmail: async () => {
+					throw new Error("busy");
+				},
+				queuedRefresh: async () => ({
+					type: "success" as const,
+					access: "new-access",
+					refresh: "new-refresh",
+					expires: now + 60_000,
+				}),
+				resolveTokenSuccessAccount: (tokens) => ({ ...tokens }) as never,
+				persistAccounts,
+				persistAccountsAndFlagged,
+				invalidateAccountManagerCache: vi.fn(),
+				saveFlaggedAccounts,
+				now: () => now,
+				showLine: vi.fn(),
+			}),
+		).rejects.toThrow("busy");
+
+		expect(persistAccounts).not.toHaveBeenCalled();
+		expect(saveFlaggedAccounts).not.toHaveBeenCalled();
+	});
+
 	it("leaves flagged state untouched when persistAccounts throws EBUSY", async () => {
 		const now = 10_000;
 		const saveFlaggedAccounts = vi.fn(async () => {});