Self-repository action references fail on unrelated dangling symlinks

Description

The new $/ self-repository action syntax fails during Set up job when the repository contains an unrelated dangling symbolic link.

The referenced composite action is self-contained and does not access the symlink. The job fails before any action step executes.

Minimal reproduction

Repository:

https://github.com/khitrenovich/actions-self-reference-symlink-repro

Public failing run:

https://github.com/khitrenovich/actions-self-reference-symlink-repro/actions/runs/31539160416

The repository contains:

• .github/actions/noop/action.yml: a self-contained no-op composite action
• .github/workflows/reproduce.yml: invokes uses: $/.github/actions/noop
• unrelated-link: a tracked symlink (Git mode 120000) pointing to the intentionally absent generated/missing.txt

The workflow is:

name: Reproduce self-repository symlink failure

on:
  push:
  workflow_dispatch:

permissions:
  contents: read

jobs:
  reproduce:
    runs-on: ubuntu-latest
    steps:
      - name: Use same-repository action
        uses: $/.github/actions/noop

Actual behavior

The runner fails during job setup:

Could not find file '/home/runner/work/_actions/_temp_13dfc312-ad75-4ec4-9a00-429d60560a56/_staging/actions-self-reference-symlink-repro-0a86ba71675c525265c5c3fb7087a12f47c89cb5/unrelated-link'.

No workflow step executes.

Expected behavior

The runner should load .github/actions/noop and execute it. A dangling symlink elsewhere in the repository should not affect loading an unrelated action.

At minimum, repository staging should preserve a tracked symlink without dereferencing its target. Ideally, loading an action from a subdirectory should not require unrelated repository paths to be staged.

Environment

• GitHub-hosted runner
• Runner version: 2.336.0
• Image: ubuntu-24.04
• Workflow permissions: contents: read
• No secrets or third-party actions

Additional context

Replacing the self-repository reference with ./.github/actions/noop after actions/checkout avoids this failure.

The self-repository implementation resolves $/path to a normal owner/repo/path@sha reference before download and notes that a repository tarball is cached:

https://github.com/actions/runner/pull/4457

Feature announcement:

https://github.blog/changelog/2026-07-30-reference-same-repository-actions-with-self-repository-syntax/

This was initially observed in a larger private repository, where concurrent jobs failed on different unrelated tracked symlinks whose generated targets are intentionally not committed. The public repository above reduces the behavior to one action and one dangling symlink.

Reproduce the failure with .github/actions/noop/action.yml, .github/workflows/reproduce.yml, the public repository, and the failing run; then inspect the self-repository implementation and linked PR 4457. Done means the self-contained action runs during Set up job even when unrelated-link is a tracked dangling symlink, without dereferencing its missing target.