Doesn't resolve modules with pnpm

[timsuchanek]

pnpm is not using hoisting, but always nests the node_modules.
It seems like this doesn't work with esbuild.
Here is a simple repro: https://github.com/timsuchanek/esbuild-pnpm

[evanw]

Caveat: I'm totally unfamiliar with pnpm.

Thanks for the simple repro case! It was very straightforward to reproduce the issue.

I'm just reading up on this tool now. I noticed that the FAQ (https://pnpm.js.org/en/faq) says this:

pnpm does not work with <YOUR-PROJECT-HERE>?

In most cases it means that one of the dependencies require packages not declared in package.json. It is a common mistake caused by flat node_modules. If this happens, this is an error in the dependency and the dependency should be fixed. That might take time though, so pnpm supports workarounds to make the buggy packages work.

...

Solution 3

In case there are too many issues, you can use the shamefully-hoist config. This creates a flat node_modules structure similar to the one created by npm or yarn.

To use it, try pnpm install --shamefully-hoist.

I can verify that if you follow your instructions and do pnpm install followed by pnpm run build then the build fails. These are the specific errors:

node_modules/chalk/source/index.js:2:27: error: Could not resolve "ansi-styles"
const ansiStyles = require('ansi-styles');
                           ~~~~~~~~~~~~~
node_modules/chalk/source/index.js:3:59: error: Could not resolve "supports-color"
const {stdout: stdoutColor, stderr: stderrColor} = require('supports-color');
                                                           ~~~~~~~~~~~~~~~~

However, if I do pnpm install --shamefully-hoist followed by pnpm run build then everything works fine.

Does this mean that, as the FAQ says, this is an error in the dependency? Sorry if that's not the case. I've never used pnpm before.

Also: Is there a description of the changes to the module resolution algorithm that I'd need to use to support pnpm? Node has a great reference for its module resolution algorithm, for example: https://nodejs.org/api/modules.html#modules_all_together.

[timsuchanek]

Thanks for the answer @evanw!
To be honest, I also don't understand enough, why the Node.js module resolution works in my example and what exactly pnpm is doing under the hood. I pinged the author of the library to give us an explanation here about how the module resolution algorithm would have to be adjusted in esbuild.

The --shamefully-hoist is not an option for us, because it slows installation down (we have a big workspace) and we have globally conflicting TypeScript types (of jest and mocha), which would conflict with hoisting, but are not conflicting with the pnpm module isolation.

[zkochan]

@evanw seems like the issue is that esbuild does not use the real location of the files when resolving dependencies. The real location of chak is not at node_modules/chalk. The real location is at node_modules/.pnpm/registry.npmjs.org/chalk/4.0.0/node_modules/chalk.

node_modules/chalk is a symlink to node_modules/.pnpm/registry.npmjs.org/chalk/4.0.0/node_modules/chalk. Any bundlers should resolve modules to their real location and resolve dependencies from that location (this is how Node's resolution algorithm works). Dependencies of chalk are at node_modules/.pnpm/registry.npmjs.org/chalk/4.0.0/node_modules/

[evanw]

That's very helpful! It'll probably be a little tricky to fix this without regressing performance. It looks like the naive approach is a big performance hit. I'll have to figure out a caching strategy.

It seems like this doesn't work in Parcel either. I believe parcel-bundler/parcel#1125 is the corresponding issue.

[evanw]

Just gave fixing it a shot. The module resolution algorithm should now return the real location instead of the symlink location. Please let me know if that works for you or not.

[timsuchanek]

The fix works! Thanks a lot!

[SevereOverfl0w]

Unfortunately, this does break npm install to a directory, which creates a symlink. The parcel issue also discusses this. Their solution to this is to act differently when the package.json contains "source": true.

[jackyef]

Hi @evanw , I just tried this on a windows machine (0.6.5, installed from npm) but the build fails with the same error as described in your earlier comment. Has this regressed since then?