Setting node.__dirname to false doesn't work with ffi-napi, ref-napi libraries with electron js

Bug report

What is the current behavior? Using webpack in the electron js app I can’t import native module libraries like ffi-napi, ref-napi, etc in my application. Libraries like those generally expects node’s __dirname to set as global. Thus, setting node: {__dirname: true} would work in my app but in the production built it throws a runtime error:

Error: No native build was found for platform=darwin arch=x64 runtime=electron abi=87 uv=1 libc=glibc node=14.16.0 electron=12.0.6 webpack=true

The same above error would throws if I change/remove node:{__dirname: false} or node property itself from the webpack config.

If the current behavior is a bug, please provide the steps to reproduce. I’m not sure on this whether its a bug or not. But to reproduce the scenario here’s my example repo which can show the issue in more details. Basically,

to reproduce an error

• start the app by npm start
• then an error would shown up

to get working

• change the __dirname to true in the webpack.config.js and again
• start the app by npm start
• now it runs OK. To confirm if native module ffi-napi, ref-napi are working properly - goto View > Toggle Developer Tools and in the console tab = Add: 8

What is the expected behavior? If I need to set node:{__dirname: true} in this case (which works in the development mode) then the same behavior is expected to be working in the production mode (in the installer). Otherwise, if there is/are other work around to fix then still the expectation is same as to the development mode at the moment.

Other relevant information: webpack version: ^5.37.0 Node.js version: 14.16.0 Operating System: macOS 10.14.6 Additional tools: ffi-napi ver. ^4.0.3, ref-napi ver. ^3.0.2, webpack-cli ver. ^4.7.0, electron ver. ^12.0.7

[raviSussol]

@alexander-akait Yeah its to do with node addon path that node gyp build is expecting for building. But the __dirname varies based on the webpack config and so does the electron as well. One definitely needed to settle by providing consistent path to the directory and I fixed by using electron’s getAppPath function which always returns runtime app execution path. Node loader may not work in this case I think as libraries like ffi-napi, ref-napi themselves provide javascript apis to interact with their node addon files. However, did have to customized a bit of those libraries for me to get working. Thanks for the heads up though. I think this issue can be closed now.

[alexander-akait]

hm, yes, you are right target: 'node' is not working and it is expected, we set __dirname: mock for all cases except node https://github.com/webpack/webpack/blob/master/lib/config/defaults.js#L884

The problem here is that node-gyp-build try to search file and don’t found it, because it is bundled code and be in dist directory, not in node_modules (in my case it is /home/akait/projects/electron-webpack-native-module-example/dist), so node-gyp-build trying to search on the wrong path. Open node_modules/node-gyp-build/index.js and debug load.path.

We have the same limitation for Node.js add-ons, you need to use https://github.com/webpack-contrib/node-loader to working with them.

I think duplicate https://github.com/webpack/webpack/issues/5424