Prerequisites

• I'm using the latest version (6.27.0)
• I've read the relevant documentation
• I've searched for existing issues
• I've checked the list of known issues
• I've read the issue reproduction guide

Reproduction url

https://github.com/grahamtt/knip-gitignore-negation-repro

Reproduction access

• I've made sure the reproduction is publicly accessible

Description of the issue

Summary: A .gitignore negation (!…) whose basename matches an ignored path un-ignores that path globally in knip, even when the negation targets a different directory. git scopes the negation correctly; knip does not, so knip analyzes files inside a git-ignored directory and reports them (e.g. as unused files).

Reproduce (npm install && npx knip in the linked repo):

Unused files (1)
build/reports/orphan.ts

build/reports/orphan.ts lives inside build/, which .gitignore ignores, so knip should not analyze it.

The trigger is one unrelated line. The .gitignore is:

node_modules/
build/
!foo/build/      <-- remove this line and the false positive disappears

!foo/build/ un-ignores foo/build/ — a non-existent, unrelated path. git still ignores the file either way:

git check-ignore build/reports/orphan.ts
# -> build/reports/orphan.ts   (git ignores it)

Delete the !foo/build/ line, rerun npx knip, and there are no unused files.

Scope of the trigger (from bisecting):

• Leaks only when the negation's basename equals an ignored path's basename. !foo/build/ leaks build/; !completely/unrelated/path/ and !keep.txt do not.
• Independent of the negation's directory prefix or trailing-slash form: !foo/build/, !x/build, and ignoring as build/** all leak identically.
• git check-ignore disagrees with knip in every leaking case.

Where it does not appear to be: the pattern converter. Feeding the same .gitignore through the exported parseAndConvertGitignorePatterns + expandIgnorePatterns, composed into picomatch(ignores, { ignore: unignores }), returns isIgnored("build/reports/orphan.ts") === true with and without the negation. So the flat pattern set looks correct. The divergence seems to arise in the directory-walk / pruning in src/util/glob-core.js, where an unignore with a colliding basename appears to stop build/ from being pruned as a directory (after which the descendant is walked and reported). That last part is a hypothesis; the black-box reproduction above is deterministic.

Expected: knip honors .gitignore with the same scoping git uses, so an unrelated negation does not cause files under an ignored directory to be analyzed.

Versions

• knip 6.27.0
• node 24.16.0