Node "Cannot read properties of undefined (reading 'then')

[maciej-wakula-opuscapita]

What happened?

Steps to Reproduce

I tried to run node -r ./tracing.js index.js.
The sdk.start().then(...) is failing - sdk.ts is returning void.
I am using plain JavaScript (not typescript).

Expected Result

sdk.start() should always return same object type: either a promise, a concrete object or undefined. If the returned object is an undefined then .then should not be called on it.

Actual Result

When using webpack - it seems to work for me most time. When using javascript - the returned argument is not a promise and has no .then

Additional Details

Test procedure

mkdir /tmp/dir && cd /tmp/dir
docker run --rm -v /tmp/dir:/home/node/dir -it node:18-alpine sh
cd /home/node/dir
npm init -y
npm i @opentelemetry/sdk-node @opentelemetry/exporter-trace-otlp-http @opentelemetry/instrumentation-fs
node -r ./tracing.js index.js

OpenTelemetry Setup Code

//tracing.js

'use strict'
const opentelemetry = require('@opentelemetry/sdk-node');
const { OTLPTraceExporter } = require('@opentelemetry/exporter-trace-otlp-http');
const { FsInstrumentation } = require('@opentelemetry/instrumentation-fs');
const traceExporter = new OTLPTraceExporter({ url: 'http://otel-collector:4318/v1/traces' });
const sdk = new opentelemetry.NodeSDK({
  traceExporter,
  instrumentations: [new FsInstrumentation()],
  autoDetectResources: true,
  resourceDetectors: [ // By default process information is also added
    opentelemetry.resources.envDetector,
  ],
});
sdk.start()
  .then(()=>console.log("Tracing initialized"))
  .catch((error)=>console.log("Error during initialization"));

package.json

{
  "name": "dir",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@opentelemetry/exporter-trace-otlp-http": "^0.36.1",
    "@opentelemetry/instrumentation-fs": "^0.7.1",
    "@opentelemetry/sdk-node": "^0.36.1"
  }
}

Relevant log output

/home/node/dir/tracing.js:16
  .then(()=>console.log("Tracing initialized"))
  ^

TypeError: Cannot read properties of undefined (reading 'then')
    at Object.<anonymous> (/home/node/dir/tracing.js:16:3)
    at Module._compile (node:internal/modules/cjs/loader:1226:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1280:10)
    at Module.load (node:internal/modules/cjs/loader:1089:32)
    at Module._load (node:internal/modules/cjs/loader:930:12)
    at Module.require (node:internal/modules/cjs/loader:1113:19)
    at Module._preloadModules (node:internal/modules/cjs/loader:1403:12)
    at loadPreloadModules (node:internal/process/pre_execution:621:5)
    at setupUserModules (node:internal/process/pre_execution:125:3)
    at prepareExecution (node:internal/process/pre_execution:116:5)

[Flarna]

Likely caused by #3460 which was unfortunately not marked as breaking.

Please note that modules like @opentelemetry/sdk-node are still in experimental phase so breaking changes like this may happen.

There is a bold note about this in the readme.

[maciej-wakula-opuscapita]

Since README.md is updated in #3460 - we can probably close this ticket.

[kzotoff]

Also, this demo is needed to be updated
https://opentelemetry.io/blog/2022/instrument-nginx/