Prerequisites

• I've read the relevant documentation
• I've searched for existing issues
• I've read the issue reproduction guide

Reproduction url

https://github.com/astegmaier/playground-knip-6-tsconfig-bug

Reproduction access

• I've made sure the reproduction is publicly accessible

Good version

5.88.1

Bad version

6.0.3

Description of the regression

When tsconfig.json has "outDir": "lib/" (with a trailing slash):

{
  "compilerOptions": {
    "outDir": "lib/",
    "srcDir": "src/"
  }
}

...and package.json has an export pointing to a lib/ path:

{
  "exports": {
    "./greet": "./lib/greet.js"
  }
  // ...
}

Knip 6 is unable to map lib/greet.js back to src/greet.ts, causing it to report src/greet.ts as an unused file, even though it's correctly exported and used.

Knip 5 handles this case fine.

It's possible to work around this by removing the trailing slash (typscript seems to requard lib/ and lib as equivalent. I thought it would be worth reporting anyways to keep things as seamless as possible for others.