Webpack entry cannot be found after importing filer

[thomas-jakemeyn]

Context

I am trying to add FilerWebpackPlugin to an existing Webpack configuration.

Problem

As soon as I require('filer'), Webpack starts failing because it cannot find the entry file anymore.

Analysis

This problem seems to be caused by a side effect in src/path.js:

/**
 * Patch process to add process.cwd(), always giving the root dir.
 * NOTE: this line needs to happen *before* we require in `path`.
 */
process.cwd = () => '/';

Workaround

The only workaround that I found is to save process.cwd before importing filer, and to restore it afterwards.

const cwd = process.cwd;
const filer = require('filer');
process.cwd = cwd;

With this fix, Webpack is able to find the entry file again.

[humphd]

cc @bcheidemann, who might have thoughts.

[bcheidemann]

Thanks for raising this issue @thomas-jakemeyn.

The problem seems to be that we import the whole of filer when we only need the FilerWebpackPlugin class. In hindsight, this is obviously not the best idea! I will put up a PR to deprecate accessing the plugin through the "normal" filer import and add a specific import path for the plugin. @humphd what do you think about:

const { FilerWebackPlugin } = require('filer/webpack');

@thomas-jakemeyn Until the fix is released, you should be able to import the class directly:

// Direct import
const FilerWebpackPlugin = require('filer/src/webpack-plugin');

Let me know if this works for you! :)

[thomas-jakemeyn]

Hello @bcheidemann,

I confirm that using a direct import as you suggested works. Thank you for that!
However, don't you think that the real problem is the side-effect on process.cwd?

[bcheidemann]

Hello @bcheidemann,

I confirm that using a direct import as you suggested works. Thank you for that! However, don't you think that the real problem is the side-effect on process.cwd?

@thomas-jakemeyn The process.cwd side effect is, as I understand it, required for filer to work properly in the browser. Maybe @humphd can clarify the exact purpose? Regardless, the Webpack config only needs to load the FilerWebpackPlugin class which does not import any part of the main filer library (nor should it). As such, if imported correctly, there should be no side-effects.

Are you having trouble with the process.cwd side effect other than in the context of the Webpack config (i.e. at runtime)?

[thomas-jakemeyn]

The problem that I was personally facing is solved with your suggestion.

[humphd]

re: the process.cwd override, that can probably be removed. It's used very rarely, and likely could be dealt with through documentation alone. Unlike fs running in the OS, we have no concept of a process on which the current working directory can be managed. We could probably move this to the shell instead. I'd take a PR that did this, but am unlikely to have time to do it any time soon.

[bcheidemann]

Thanks for the clarification @humphd.

@thomas-jakemeyn do you anticipate other issues that wouldn't be solved by PR #793? Happy to rethink our approach if there's reason to do so :)

[thomas-jakemeyn]

Since filer is intended to be used in a browser, I guess that it should be fine indeed. Thank you for the clarification and for the quick reaction!

[bcheidemann]

No problem!

@humphd shall we proceed with PR #793 so we can close this issue?

EDIT: I have seen the other issue about the shims not being present in the version distributed through npm - don't have time to address that until this evening or tomorrow but we should probably ship any fix for that with the fix for this issue imo

[humphd]

Landed #793, I'll ship v1.4.0 in a min.

[humphd]

https://github.com/filerjs/filer/releases/tag/v1.4.0

https://www.npmjs.com/package/filer is now at v1.4.0

[bcheidemann]

https://github.com/filerjs/filer/releases/tag/v1.4.0

https://www.npmjs.com/package/filer is now at v1.4.0

Thanks!