Icons Preset Node Loader does not work when using Yarn PnP

[FWest98]

UnoCSS version

0.58.8

Describe the bug

When using Yarn PnP, the icons preset does not pick up on any Iconify dependencies being present. I suspect this is caused by the "Node Loader" deferring to a filesystem lookup - this fails because when using PnP: there is no node_modules folder as all the dependencies are zipped and made available on demand when importing a dependency.

I did find a workaround by modifying the icons preset configuration:

presetIcons({
    collections: {
        "material-symbols": () => import("@iconify-json/material-symbols/icons.json").then(i => i.default)
    }
})

System Info

No response

Validations

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[antfu]

I am sorry, but I am not interested in supporting Yarn PnP.

[FWest98]

Then it would be good to mention this clearly in the documentation. The docs do include yarn example commands, and Yarn PnP has already become the default for new projects. This is related to #3566 as well.

[antfu]

That's interesting. I didn't know they are doing PnP by default now, which is also kind of sad because it requires the ecosystem to have special handling for it. In that case, I am open to contributions if the implementation is not too difficult. But supposedly, the code to fix it is not in this repo but somewhere down the line, like @iconify/utils or so.

Reopen to keep track of it.

[cyberalien]

Confirmed and trying to debug it...

When trying to debug it, found a related issue:

Installing @iconify-json/mdi...
Unknown Syntax Error: Unsupported option name ("--prefer-offline").

$ yarn add [--json] [-E,--exact] [-T,--tilde] [-C,--caret] [-D,--dev] [-P,--peer] [-O,--optional] [--prefer-dev] [-i,--interactive] [--cached] [--mode #0] ...
[@iconify-loader] Failed to install @iconify-json/mdi
Error: Command failed with exit code 1: yarn add -D --prefer-offline @iconify-json/mdi

Triggered by installPackage from @antfu/install-pkg package.

edit: option --prefer-offline does not exist in Yarn 3.6.0, so error is correct. Yarn detection is broken in @antfu/install-pkg

[cyberalien]

Figured it out. Error is caused by resolvePath from mlly package failing to resolve @iconify-json/material-symbols/icons.json, even though package is installed.

So 2 unrelated issues.