fix(client): prevent duplicate signal processing in atom listeners (#7018)

packages/better-auth/src/client/proxy.test.ts

@@ -0,0 +1,65 @@
+import { describe, expect, it, vi } from "vitest";
+import { createDynamicPathProxy } from "./proxy";
+
+describe("createDynamicPathProxy", () => {
+	it("should avoid duplicate signal processing", async () => {
+		const client = vi.fn(async (path, options) => {
+			if (options?.onSuccess) {
+				await options.onSuccess({} as any);
+			}
+			return {
+				data: {},
+				error: null,
+			};
+		});
+		const knownPathMethods = {
+			"/test": "POST",
+		} as const;
+
+		const signalSet = vi.fn();
+		const signalGet = vi.fn(() => false);
+
+		const atoms = {
+			testSignal: {
+				get: signalGet,
+				set: signalSet,
+				subscribe: () => () => {},
+				listen: () => () => {},
+				off: () => {},
+				value: false,
+			} as any,
+		};
+		const atomListeners = [
+			{
+				matcher: (path: string) => path === "/test",
+				signal: "testSignal",
+			},
+			{
+				matcher: (path: string) => path === "/test",
+				signal: "testSignal",
+			},
+		];
+
+		const proxy = createDynamicPathProxy(
+			{
+				test: {},
+			},
+			client as any,
+			knownPathMethods,
+			atoms,
+			atomListeners,
+		);
+
+		vi.useFakeTimers();
+
+		await (proxy.test as any)();
+
+		expect(client).toHaveBeenCalled();
+
+		vi.runAllTimers();
+
+		expect(signalSet).toHaveBeenCalledTimes(1);
+
+		vi.useRealTimers();
+	});
+});

packages/better-auth/src/client/proxy.ts

@@ -1,5 +1,6 @@
 import type {
 	BetterAuthClientPlugin,
+	ClientAtomListener,
 	ClientFetchOption,
 } from "@better-auth/core";
 import type { BetterFetch } from "@better-fetch/fetch";
@@ -100,9 +101,15 @@ export function createDynamicPathProxy<T extends Record<string, any>>(
 						 */
 						const matches = atomListeners.filter((s) => s.matcher(routePath));
 						if (!matches.length) return;
+
+						const visited = new Set<ClientAtomListener["signal"]>();
 						for (const match of matches) {
 							const signal = atoms[match.signal as any];
 							if (!signal) return;
+							if (visited.has(match.signal)) {
+								continue;
+							}
+							visited.add(match.signal);
 							/**
 							 * To avoid race conditions we set the signal in a setTimeout
 							 */