baseUrl + paths in transform resolves path to parent dir

[devjiwonchoi]

Describe the bug

SWC transform requires the baseUrl to be absolute path.

The common case is to use resolve to get the absolute path resolving the cwd and baseUrl.

For the following examples, I'm using process.cwd() as resolved baseUrl.

If pass process.cwd() as baseUrl to swc transform, it resolves the path as the parent folder.

It should resolve the path for the baseUrl folder and should not resolve the path for the parent folder.

Input code

import { transform } from '@swc/core'

const input = `
import { foo } from '@/foo'

console.log(foo)
`

async function main() {
  const { code } = await transform(input, {
    jsc: {
      baseUrl: process.cwd(),
      paths: {
        '@/*': ['./src/*'],
      },
    },
  })

  console.log(code)
}

main()

Config

No response

Playground link (or link to the minimal reproduction)

https://github.com/devjiwonchoi/repro-swc-base-url-paths

SWC Info output

Operating System:
    Platform: darwin
    Arch: arm64
    Machine Type: arm64
    Version: Darwin Kernel Version 23.1.0: Mon Oct  9 21:32:11 PDT 2023; root:xnu-10002.41.9~7/RELEASE_ARM64_T6030
    CPU: (11 cores)
        Models: Apple M3 Pro

Binaries:
    Node: 18.17.0
    npm: 9.6.7
    Yarn: 1.22.19
    pnpm: 8.14.2

Relevant Packages:
    @swc/core: 1.4.2
    @swc/helpers: N/A
    @swc/types: N/A
    typescript: 5.3.3

SWC Config:
    output: N/A
    .swcrc path: N/A

Next.js info:
    output: N/A

Expected behavior

It should resolve the path for the baseUrl folder and should not resolve the path for the parent folder.

import { foo } from "./src/foo"; // based on current dir

console.log(foo, bar);

Actual behavior

If pass process.cwd() as baseUrl to swc transform, it resolves the path as the parent folder.
Also, it does not resolve the path for the baseUrl folder.

import { foo } from "./repro-swc-base-url-paths/src/foo"; // parent folder

console.log(foo, bar);

Version

1.4.2

Additional context

• Duplicate of spack: jsc.paths are not relative to jsc.baseUrl #2725, but added a valid reproduction and confirming the latest version.
• This fix is needed for Next.js PR#57656.

[devjiwonchoi]

Confirmed that it is fixed by v1.4.3-nightly-20240226.1

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.