Fix Workspace Circular Symlink

[mattietea]

Issue

Knip hangs indefinitely when analyzing workspaces containing circular symlinks in node_modules. This occurs in monorepos where workspace-to-workspace symlinks create circular references

Root Cause

The syncGlob function in src/util/glob.ts uses fast-glob with default options, which includes followSymbolicLinks: true. When encountering circular symlinks, fast-glob enters an infinite traversal loop.

Fix

Added followSymbolicLinks: false to the syncGlob function.

I noticed there is also GLOBAL_IGNORE_PATTERNS - is that the better fix?

Impact

Before:

• Analysis hangs indefinitely on workspaces with circular symlinks

After:

• Correctly finds files without traversing symlinks

[mattietea]

Perhaps GLOBAL_IGNORE_PATTERNS is the better fix?

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/knip@1319

commit: 26c5eac

[webpro]

Thanks for the PR!

I do wonder if this actually fixes the issue you described. The fixture currently doesn't seem to fail without this change. So could you please set up something that fails/hangs first so that we have something to work with?

[mattietea]

Thanks for the PR!

I do wonder if this actually fixes the issue you described. The fixture currently doesn't seem to fail without this change. So could you please set up something that fails/hangs first so that we have something to work with?

Hi Lars,

Thanks for taking a look at this! Hmm, I seem to be getting the failure.

I thought there might be issues with symlinks and GitHub, so I tried deleting the branch locally and checking it out again but that seems to have worked. Let me know if you have any other ideas! I'm running the test with

bun test ./packages/knip/test/workspaces-circular-symlinks.test.ts

Without Changes

const syncGlob = ({ cwd, patterns }: { cwd?: string; patterns: string | string[] }) =>
  fg.sync(patterns, { cwd });

bun test ./packages/knip/test/workspaces-circular-symlinks.test.ts
bun test v1.2.15 (df017990)

packages/knip/test/workspaces-circular-symlinks.test.ts:
11 | test('syncGlob should not traverse circular symlinks', () => {
12 |   const libACwd = resolve('fixtures/workspaces-circular-symlinks/packages/lib-a');
13 |   const files = _syncGlob({ patterns: ['./**/*.ts'], cwd: libACwd });
14 |
15 |   const expected = 1;
16 |   assert.equal(files.length, expected, `Expected ${expected} file but found ${files.length}`);
              ^
AssertionError: Expected 1 file but found 32

32 !== 1

 generatedMessage: false,
     actual: 32,
   expected: 1,
   operator: "strictEqual",
       code: "ERR_ASSERTION"

      at /Users/mattietea/Desktop/knip/packages/knip/test/workspaces-circular-symlinks.test.ts:16:10
✗ syncGlob should not traverse circular symlinks [8.60ms]

 0 pass
 1 fail
Ran 1 tests across 1 files. [57.00ms]

We can see in this test _globSync is returning the same path 32 times

Truncated return value of _globSync

[
  "index.ts", "node_modules/@fixtures/lib-b/index.ts", "node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/index.ts",
  "node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/index.ts",
  "node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/index.ts",
  "node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/index.ts",
  "node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/index.ts",
  "node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/index.ts",
  "node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/node_modules/@fixtures/lib-b/node_modules/@fixtures/lib-a/index.ts",
  ...
]

With Changes

const syncGlob = ({ cwd, patterns }: { cwd?: string; patterns: string | string[] }) =>
  fg.sync(patterns, { cwd, followSymbolicLinks: false });

bun test ./packages/knip/test/workspaces-circular-symlinks.test.ts
bun test v1.2.15 (df017990)

packages/knip/test/workspaces-circular-symlinks.test.ts:
✓ syncGlob should not traverse circular symlinks [2.71ms]

 1 pass
 0 fail
Ran 1 tests across 1 files. [53.00ms]

[webpro]

Thanks Matt! Confirmed & merged.

[webpro]

🚀 This pull request is included in v5.78.0. See Release 5.78.0 for release notes.

Using Knip in a commercial project? Please consider becoming a sponsor.