Knip output differs depending on the presence of dist

[alecmev]

Hi! I finally updated Knip from 2.41.5 to 4.0.3 and it told me to move some type-only dependencies from devDependencies to dependencies, which I did (this is desired). Then I pushed these changes and Knip failed in CI, asking me to do the exact opposite of the above. The only difference is the absence of dist directories, as we don't build before static checks.

Made a repro. Run npm run test and observe this:

Unused dependencies (1)
@org/foo  packages/bar/package.json

Then run npm run build and npm run test again, no error.

Seems like some sort of composite project issue? Not sure.

[webpro]

Quoting from https://knip.dev/features/production-mode#strict-mode:

• Type-only imports should be in devDependencies

Unfortunately there's no clear-cut solution for this yet.

Related to #248.

[alecmev]

To clarify, I don't feel that strongly about whether it should be in dependencies or devDependencies, I understand that it's an ecosystem problem, but I do want Knip to be consistent about it 😛 In this case, Knip wants type-only deps to be in devDependencies if there is no dist, and in dependencies if there is a dist, which seems to be a bug.

[webpro]

It's a bit of double-edged sword: adding dist/index.js will include it in the program, since it's being referred to.

(This is how the TypeScript backend works w/ ts.createProgram()).

The correct result in this case seems to be that there are no unused dependencies. There's no way for Knip to understand that e.g. /dist/index.js should map to src/index.ts (regardless of the presence of the former). I understand the annoyance, but at this point there isn't much I can do about it. That's why I'm going to close this issue.

Related/similar: #472 (comment)

[alecmev]

Is dist included in the repro I posted though? It’s both specified as an outDir in tsconfig.json and listed in .gitignore, I would expect Knip to ignore it, or is that assumption wrong?

[webpro]

Knip ignores it, but the TypeScript backend does not.

[alecmev]

Just in case, this happens only in a monorepo. When I was trying to come up with a repro, I couldn't get it with just a simple plain package. If you go to the same repro above, do an npm run build, cd packages/bar and run npx knip --production --strict, you'll get the desired output (ignore "unused files", it's due to the lack of a local .gitignore):

Unused dependencies (1)
@org/foo  package.json

Then do a cd ../.. and run npx knip --production --strict again, no errors. There must be more to this?