ReferenceError when "module" string is present in incoming webhooks

Description:

The presence of the "module" string, either with quote or without trigger ReferenceError in incoming webhook scripts.

Steps to reproduce:

1. Create an incoming webhook
2. Add a script with a module string inside like :

class Script {
  process_incoming_request({ request }) {
    console.log(request.content);
    return { content: { alias: "foo", text: "module"} };
  }
}

3. Trigger it.

curl -X POST -H 'Content-Type: application/json' --data '{"foo":"bar"}' http://localhost/hooks/***/***

Expected behavior:

I20210323-14:46:40.935(0) Integrations ➔ Incoming WebHook.info Post integration: Foo Webhook
I20210323-14:46:40.936(0) Integrations ➔ Incoming WebHook.info Will evaluate script of Trigger Foo Webhook
{ foo: 'bar' }

Actual behavior:

I20210323-14:42:14.393(0) Integrations ➔ Incoming WebHook.info Post integration: Foo Webhook
I20210323-14:42:14.394(0) Integrations ➔ Incoming WebHook.info Will evaluate script of Trigger Foo Webhook
I20210323-14:42:14.398(0) server.js:204 Integrations ➔ Incoming WebHook.error [Error evaluating Script in Trigger Foo Webhook :]
I20210323-14:42:14.399(0) server.js:204 Integrations ➔ Incoming WebHook.error !function(module1){var Script=function(){function Script(){}var _proto=Script.prototype;_proto.process_incoming_request=function process_incoming_request(_ref){var request=_ref.request;console.log(request.content);return{content:{alias:"foo",text:"module"}}};return Script}()}.call(this,module);
I20210323-14:42:14.399(0) server.js:204 Integrations ➔ Incoming WebHook.error [Stack:]
I20210323-14:42:14.402(0) server.js:204 Integrations ➔ Incoming WebHook.error script.js:1 !function(module1){var Script=function(){function Script(){}var _proto=Script.prototype;_proto.process_incoming_request=function process_incoming_request(_ref){var request=_ref.request;console.log(request.content);return{content:{alias:"foo",text:"module"}}};return Script}()}.call(this,module); ^ ReferenceError: module is not defined at script.js:1:226 at Script.runInContext (vm.js:130:18) at Script.runInNewContext (vm.js:135:17) at getIntegrationScript (app/integrations/server/api/api.js:70:12) at Object.executeIntegrationRest (app/integrations/server/api/api.js:166:13) at app/api/server/api.js:394:82 at Meteor.EnvironmentVariable.EVp.withValue (packages/meteor.js🔢12) at Object._internalRouteActionHandler [as action] (app/api/server/api.js:394:39) at Route.share.Route.Route._callEndpoint (packages/nimble_restivus/lib/route.coffee:150:32) at packages/nimble_restivus/lib/route.coffee:59:33
I20210323-14:42:14.403(0) Integrations ➔ Incoming WebHook.warn { statusCode: 400, body: { success: false, error: 'error-evaluating-script', stack: undefined } }

Server Setup Information:

• Version of Rocket.Chat Server: 3.12.1 HEAD: (f2817c056)
• Operating System: Debian GNU/Linux
• Deployment Method: docker (rocketchat/rocket.chat:latest)
• Number of Running Instances: 1
• NodeJS Version: v12.18.4
• MongoDB Version: 4.0.23 / wiredTiger (oplog Enabled)

Additional context

Our real usage are prometheus alerts, which may define data to process in request.content.alerts[0].labels.module key. Either test its presence with if ("module" in alert.labels) { ... } or access it with alert.labels.module raise a ReferenceError.

Start in app/integrations/server/api/api.js, especially getIntegrationScript and executeIntegrationRest, and reproduce the incoming webhook with a script containing the string or property name "module". Trace why evaluation treats that reference as unavailable. Done means the webhook script runs successfully and returns its content without a ReferenceError.