runInDebug() not stripped in production

[mydea]

I am using ember-source 3.18.0, and just noticed that runInDebug is not stripped from production builds.

This is my code:

import Route from '@ember/routing/route';
import { runInDebug } from '@ember/debug';

export default class ApplicationRoute extends Route {
  beforeModel() {
    runInDebug(() => {
      // do something
    });
    // ...
  }
}

I noticed on our CI that the build size increased whenever I added something inside of the runInDebug method. I then ran the build locally (ember b --prod) and checked the generated app.js file, and indeed the whole method with all the content was still there.

Note: It is not actually run it production, but the code is still in the bundle.

[mydea]

I made a minimal reproduction here:

https://github.com/mydea/ember-issue-reproductions/tree/run-in-debug

Steps to reproduce:

• Run ember b --prod
• Go to dist/assets/ember-issue-reproductions.js
• Search for runInDebug, see that the whole function body is still in there

I also tried it all the way down to 3.8, with no change.

[pzuraq]

Hmm, this function was added in 1.5 and isn't the modern way of doing this. We currently recommend that you use the DEBUG flag, which is more flexible:

import Route from '@ember/routing/route';
import { DEBUG } from '@glimmer/env';

export default class ApplicationRoute extends Route {
  beforeModel() {
    if (DEBUG) {
      // do something
    }
    // ...
  }
}

This is more inline with the wider ecosystem (which uses NODE_ENV in general). The way it works is it gets turned to true/false depending on environment, and then Terser/Uglify remove it because they recognize it as dead code.

We do document the runInDebug function though and say that it is stripped in production, the docs may need to be updated. I'll look into this.

[pzuraq]

For reference, the debug stripping/tooling that is definitely supported is documented in ember-cli-babel's README: https://github.com/babel/ember-cli-babel#debug-tooling

[mydea]

Yeah, I was actually looking around in the docs searching for exactly this, then stumbled over runInDebug() and though that this would work as well.

It would probably also make sense to document import { DEBUG } from '@glimmer/env'; somewhere in the ember guides - I wouldn't think to search for this in ember-cli-babel :)

[mydea]

I will also write up an RFC to actually deprecate this functionality... :)

[mydea]

For reference: emberjs/rfcs#619

[pzuraq]

Confirmed with Rob that we never actually supported it being stripped. It should not run in production, but it won't get stripped. Given we have different APIs that overlap here, I think we should update the API docs and also point them to the other APIs.

[locks]

Closed as resolved.