exports and node_modules inside package resolving broken

[alexander-akait]

@alexander-akait I think you closed my issue prematurely, though granted it was a bit inaccurate.

I've done a bit more digging - the key difference between the node_modules folders that npm and yarn generate is that yarn creates node_module folders in each dep where their deps have cli tools with a nested .bin folder and npm does not.

So from the above, ipfs-unixfs-importer depends on rabin-wasm which has a cli tool.

With npm I get:

my-project/
├── node_modules/
│   ├── .bin/
│   │   └── rabin-wasm
.. other files
│   ├── ipfs-unixfs-importer/
|   |   └── package.json // etc

With yarn I get:

my-project/
├── node_modules/
│   ├── .bin/
│   │   └── rabin-wasm
.. other files
│   ├── ipfs-unixfs-importer/
│   │   ├── node_modules/
│   │   │   └── .bin/
│   │   │       └── rabin-wasm
|   |   └── package.json // etc

If I remove (or rename) the nested my-project/node_modules/ipfs-unixfs-importer/node_modules folder everything works, if I leave it, webpack does not resolve the rabin-wasm dependency. I guess it doesn't walk back up the tree to find the next node_modules folder if the first one doesn't have the dep it's looking for like node does?

You can see this yourself with the repro repo.

Originally posted by @achingbrain in webpack/webpack#14268 (comment)

[alexander-akait]

@achingbrain we have a bug, somewhat critical

exports example:

"exports": {
    ".": {
      "browser": "./esm/src/index.js",
      "require": "./cjs/src/index.js",
      "import": "./esm/src/index.js"
    }
  }

Reproducible:

• we have package node_modules/package-1 with node_modules and the exports field
• we try to load package-2 inside node_modules/package-1/index.js
• due ModulesInHierachicDirectoriesPlugin logic we try to search in node_modules/package-1/node_modules/package-2 , (using - request - ./package-2 and path - node_modules/package-1/node_modules)
• package-2 doesn't exist
• but because we apply ExportsFieldPlugin plugin we try to search in the exports field and ./package-2returnbrowser entry from theexports` field

[alexander-akait]

Let's wait @sokra answer, fix is easy, we should skip resolving in ExportsFieldPlugin when we try to resolve file from ModulesInHierachicDirectoriesPlugin

[achingbrain]

I think this problem also exists for enahnced-resolve@4.x.x, is there any possibility a fix can be backported for those still using webpack 4 (e.g. react-scripts, etc)?

[alexander-akait]

@achingbrain i am afraid v4 accept only security fixes, what is the blocker to update?