From 94e04c6a96e077b718f81f2b7eda26e3062c8bf4 Mon Sep 17 00:00:00 2001
From: Taesu <166604494+bytaesu@users.noreply.github.com>
Date: Thu, 20 Aug 2026 11:04:38 +0000
Subject: [PATCH] test(e2e): cover concurrent async context initialization in
 Workerd (#10847)

---
 .../test/fixtures/cloudflare/package.json     |  1 +
 .../test/fixtures/cloudflare/src/index.ts     | 59 +++++++++++++++++++
 .../cloudflare/test/cold-start.test.ts        | 30 ++++++++++
 pnpm-lock.yaml                                |  3 +
 4 files changed, 93 insertions(+)
 create mode 100644 e2e/smoke/test/fixtures/cloudflare/test/cold-start.test.ts

diff --git a/e2e/smoke/test/fixtures/cloudflare/package.json b/e2e/smoke/test/fixtures/cloudflare/package.json
index 84c1090007..639cd13b33 100644
--- a/e2e/smoke/test/fixtures/cloudflare/package.json
+++ b/e2e/smoke/test/fixtures/cloudflare/package.json
@@ -2,6 +2,7 @@
   "name": "@better-auth-test/fixtures-cloudflare",
   "private": true,
   "dependencies": {
+    "@better-auth/core": "workspace:*",
     "@better-auth/sso": "workspace:*",
     "better-auth": "workspace:*",
     "drizzle-orm": "^0.45.2",
diff --git a/e2e/smoke/test/fixtures/cloudflare/src/index.ts b/e2e/smoke/test/fixtures/cloudflare/src/index.ts
index 68b0df39ed..0a90ce8bd9 100644
--- a/e2e/smoke/test/fixtures/cloudflare/src/index.ts
+++ b/e2e/smoke/test/fixtures/cloudflare/src/index.ts
@@ -1,3 +1,14 @@
+import type { AuthEndpointContext } from "@better-auth/core/context";
+import {
+	getCurrentAdapter,
+	getCurrentAuthContext,
+	runWithEndpointContext,
+	runWithTransaction,
+} from "@better-auth/core/context";
+import type {
+	DBAdapter,
+	DBTransactionAdapter,
+} from "@better-auth/core/db/adapter";
 import { sso } from "@better-auth/sso";
 import { betterAuth } from "better-auth";
 import { drizzleAdapter } from "better-auth/adapters/drizzle";
@@ -27,6 +38,54 @@ const app = new Hono<{
 	};
 }>();
 
+// Keep this before the auth middleware to test first-time async context initialization.
+app.get("/async-context/concurrency", async (c) => {
+	const contexts = Array.from(
+		{ length: 32 },
+		() => ({}) as AuthEndpointContext,
+	);
+	const currentContexts = await Promise.allSettled(
+		contexts.map((context) =>
+			runWithEndpointContext(context, async () => {
+				await Promise.resolve();
+				return getCurrentAuthContext();
+			}),
+		),
+	);
+
+	const adapters = Array.from({ length: 32 }, () => {
+		const transactionAdapter = {} as DBTransactionAdapter;
+		const adapter = {
+			transaction: async <R>(
+				callback: (trx: DBTransactionAdapter) => Promise<R>,
+			) => callback(transactionAdapter),
+		} as DBAdapter;
+		return { adapter, transactionAdapter };
+	});
+	const currentAdapters = await Promise.allSettled(
+		adapters.map(({ adapter }) =>
+			runWithTransaction(adapter, async () => {
+				await Promise.resolve();
+				return getCurrentAdapter(adapter);
+			}),
+		),
+	);
+
+	return c.json({
+		endpointContextMatches: currentContexts.filter(
+			(currentContext, index) =>
+				currentContext.status === "fulfilled" &&
+				currentContext.value === contexts[index],
+		).length,
+		transactionAdapterMatches: currentAdapters.filter(
+			(currentAdapter, index) =>
+				currentAdapter.status === "fulfilled" &&
+				currentAdapter.value === adapters[index]?.transactionAdapter,
+		).length,
+		total: contexts.length,
+	});
+});
+
 app.use("*", async (c, next) => {
 	const auth = createAuth(c.env);
 	c.set("auth", auth);
diff --git a/e2e/smoke/test/fixtures/cloudflare/test/cold-start.test.ts b/e2e/smoke/test/fixtures/cloudflare/test/cold-start.test.ts
new file mode 100644
index 0000000000..147159f9c2
--- /dev/null
+++ b/e2e/smoke/test/fixtures/cloudflare/test/cold-start.test.ts
@@ -0,0 +1,30 @@
+import { afterAll, beforeAll, expect, it } from "vitest";
+import { createTestHarness } from "wrangler";
+
+const server = createTestHarness({
+	workers: [{ configPath: "./wrangler.json" }],
+});
+
+beforeAll(async () => {
+	await server.listen();
+});
+
+afterAll(async () => {
+	await server.close();
+});
+
+/**
+ * @see https://github.com/better-auth/better-auth/issues/10832
+ */
+it("preserves async contexts across concurrent first calls in the Workers runtime", async () => {
+	const response = await server.fetch(
+		"http://localhost:8787/async-context/concurrency",
+	);
+	expect(response.status).toBe(200);
+	const body: unknown = await response.json();
+	expect(body).toEqual({
+		endpointContextMatches: 32,
+		transactionAdapterMatches: 32,
+		total: 32,
+	});
+});
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 02b47bc6c5..c0ddb15449 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -807,6 +807,9 @@ importers:
 
   e2e/smoke/test/fixtures/cloudflare:
     dependencies:
+      '@better-auth/core':
+        specifier: workspace:*
+        version: link:../../../../../packages/core
       '@better-auth/sso':
         specifier: workspace:*
         version: link:../../../../../packages/sso