minor tweak: do not send error param leftover from /login validatio…

…n to `/authorize` route

e2e/authentication.spec.ts

@@ -77,6 +77,26 @@ test("Login should preserve query parameters on validation error", async ({ page
 	expectQueryParametersToBePreserved(page.url());
 });
 
+test("Login should remove error query parameter once user inputs correct credentials", async ({
+	page,
+}) => {
+	await page.goto(
+		"/login?client_id=123&response_type=code&redirect_uri=https://www.example.com&scope=openid",
+	);
+
+	// Cause the error by submitting invalid data.
+	await page.getByRole("button", { name: "Sign in" }).click();
+	await expect(page.getByText("Wrong username or password.")).toBeVisible();
+	expect(page.url()).toContain("error=1");
+
+	// Enter correct credentials.
+	await page.getByLabel(/Username/).fill("MarkS");
+	await page.getByLabel(/Password/).fill("test");
+	await page.getByRole("button", { name: "Sign in" }).click();
+	expectQueryParametersToBePreserved(page.url());
+	expect(page.url()).not.toContain("error=1");
+});
+
 function expectQueryParametersToBePreserved(url: string) {
 	const loginPageSearchParams = new URL(url).searchParams;
 	expect(loginPageSearchParams.get("client_id")).toEqual("123");

routes/frontend.ts

@@ -161,12 +161,11 @@ export default async function frontend(fastify: FastifyInstance) {
 			await signInUser(user.id, reply.setCookie.bind(reply) as SetCookieHandler);
 
 			// If there are Oauth2 parameters in the query string redirect user back to /authorize endpoint
-			// to approve/deny the request.
+			// so the user can approve or deny the authorization request.
 			// We check that query string parameters are valid there.
 			if (request.query.redirect_uri) {
-				// TODO do not send error param
-				// const { error, ...oauth2Params } = request.query;
-				return reply.redirect(`/authorize?${querystring.stringify(request.query)}`);
+				const { error, ...oauth2Params } = request.query; // Remove the error parameter if present.
+				return reply.redirect(`/authorize?${querystring.stringify(oauth2Params)}`);
 			}
 
 			return reply.redirect("/");