ls --affected accuracy issue when root package.json or turbo.json changes

[0xb4lamx]

Verify canary release

• I verified that the issue exists in the latest Turborepo canary release.

Link to code that reproduces this issue

https://github.com/0xb4lamx/turborepo-ls-affected-accuracy-issue

Which canary version will you have in your reproduction?

2.5.6

Expected behavior

on changes to root package.json:

• turbo ls --affected should only list packages that are actually affected by the change.

Note: According to Turborepo 2.1 release note, turbo ls --affected --output=json was introduced as a recommended replacement for turbo build --dry=json when you only need to retrieve a list of changed packages.

Actual behavior

on any random change to the root package.json:

• turbo ls --affected shows ALL packages as affected regardless of the change.
• turbo build --dry-run=json shows clear cache hit! (correct actual+expected behavior)

To Reproduce

1. Create a simple Turborepo with any packages:

   npx create-turbo@latest test-repo
   cd test-repo

2. Build to create initial cache:

   pnpm install
   pnpm turbo build  # This creates the cache that we'll test against

3. Make a minimal change to root package.json:

   # Add a space before the opening brace on line 1
   sed -i '' '1s/{/ {/' package.json
   # Or manually edit.  (add any random white space)

4. Check what turbo ls --affected shows:

   pnpm turbo ls --affected

   Result: Shows ALL packages as affected ❌

5. Check what turbo build --dry=json shows:

   pnpm turbo build --dry=json | jq -c '. as $root | .tasks[] | { taskId, cache: .cache.status }'

   Result: Shows ALL packages as "cache":"HIT" ✅

Additional context

this GH action job run could easily showcase the issue:

more details: https://github.com/0xb4lamx/turborepo-ls-affected-accuracy-issue/actions/runs/17892941470/job/50875748218.

I think --affected need to be more intelligent when handling changes to the root package.json (and turbo.json). A change in those files should not automatically mark all packages as affected unless the change actually impacts them.