fix(cloudflare/workers): simulate inbound email in alchemy dev

[Mkassabov]

Cloudflare.email().subscribe(...) did not work under alchemy dev, in two independent ways.

Handlers have to live on the bridge prototype

workerd resolves JSRPC methods only on the target entrypoint's prototype chain. An own instance property of the same name shadows the prototype entry and the lookup fails outright — it does not fall back:

TypeError: The RPC receiver does not implement the method "email".

WorkerBridge assigned the whole handler set in the constructor, leaving throwing stubs on the prototype. Move the real dispatch onto the prototype and drop the stubs:

-      for (const methodName of ExportedHandlerMethods) {
-        (this as any)[methodName] = async (input: any) => processEvent(...);
-      }
-
       return new Proxy(this, { /* user-shape RPC fallback */ });

 for (const method of ExportedHandlerMethods) {
   Object.defineProperty(WorkerBridge.prototype, method, {
-    value: function () {
-      throw new Error(`Bridge method '${method}' was called before instance setup`);
-    },
+    value: function (this: any, input: any) {
+      return processEvent(
+        (built) => built.export[method](input, this.env, this.ctx),
+        this.ctx,
+        this.env,
+        (exit) => exit._tag === "Success"
+          ? Promise.resolve(exit.value)
+          : Promise.reject(Cause.squash(exit.cause)),
+      );
+    },

fetch/scheduled/queue never hit this path — workerd dispatches those as built-in events. The local runtime is the exception: its entry worker forwards the /cdn-cgi/handler/email trigger route to the user worker as env[USER_WORKER].email(message), a plain JSRPC call. So inbound email was the one handler that worked deployed and 500'd in dev.

Isolated with four workerd probes, calling .email() over a service binding:

entrypoint shape	result
prototype method	resolves
own property assigned in constructor	does not implement the method
own property + prototype stub	does not implement the method
prototype method + constructor Proxy	resolves

Dev must not touch real Email Routing

Email resources have no local providers, so email({ zone }).subscribe(...) provisioned a real Email.Routing toggle and Email.CatchAll during alchemy dev — pointing a live zone's catch-all at a script that was never uploaded. If that landed it would silently take over inbound mail for the whole zone and drop it.

+const dev = yield* Effect.serviceOption(AlchemyContext).pipe(
+  Effect.map((ctx) => (ctx._tag === "Some" ? ctx.value.dev : false)),
+);
+
-if (!globalThis.__ALCHEMY_RUNTIME__ && props.zone !== undefined) {
+if (!globalThis.__ALCHEMY_RUNTIME__ && props.zone !== undefined && !dev) {

Local inbound is driven by the trigger route instead, which reaches the same registered listener.

EmailEventSource.local.test.ts covers the accept path and setReject end-to-end against the local simulator, and guards the prototype placement — CronEventSource.local.test.ts cannot, since scheduled never goes over RPC.

[alchemy-version-bot]

Install the packages built from this commit:

Alchemy

alchemy

bun add https://pkg.ing/alchemy/bbcb783

@alchemy.run/better-auth

bun add https://pkg.ing/@alchemy.run/better-auth/bbcb783

@alchemy.run/cloudflare-runtime

bun add https://pkg.ing/@alchemy.run/cloudflare-runtime/bbcb783

@alchemy.run/frontend-frameworks

bun add https://pkg.ing/@alchemy.run/frontend-frameworks/bbcb783

@alchemy.run/node-utils

bun add https://pkg.ing/@alchemy.run/node-utils/bbcb783

@alchemy.run/pr-package

bun add https://pkg.ing/@alchemy.run/pr-package/bbcb783

@alchemy.run/floci

bun add https://pkg.ing/@alchemy.run/floci/bbcb783

Distilled

@distilled.cloud/core

bun add https://pkg.ing/@distilled.cloud/core/809f3d8

@distilled.cloud/aws

bun add https://pkg.ing/@distilled.cloud/aws/809f3d8

@distilled.cloud/axiom

bun add https://pkg.ing/@distilled.cloud/axiom/809f3d8

@distilled.cloud/cloudflare

bun add https://pkg.ing/@distilled.cloud/cloudflare/809f3d8

@distilled.cloud/hetzner

bun add https://pkg.ing/@distilled.cloud/hetzner/809f3d8

@distilled.cloud/neon

bun add https://pkg.ing/@distilled.cloud/neon/809f3d8

@distilled.cloud/planetscale

bun add https://pkg.ing/@distilled.cloud/planetscale/809f3d8