actions/checkout fails on Windows runners when repository contains branch prefixes differing only by case

[manudrive04-hue]

:

Description

What happened?

actions/checkout fails on Windows runners during the "Determining the checkout info" phase when the repository contains branches whose path components differ only by case.

Example branches:

• feature/manu
• Feature/tarun

The checkout succeeds on Linux runners but fails on Windows runners.

Reproduction

Repository contains:

feature/manu
Feature/tarun

Workflow:

steps:
  - uses: actions/checkout@v6

Run on:

runs-on: windows-latest

Expected behavior

Checkout should either:

1. Complete successfully, or


2. Fail with a clear error indicating that the repository contains refs that cannot coexist on a case-insensitive filesystem.



Actual behavior

Checkout fails while determining checkout information / fetching refs on Windows runners.

Environment

actions/checkout: v6.0.3

Runner OS: Windows

GitHub-hosted runner


Additional context

The issue appears related to Windows case-insensitive filesystem behavior when refs contain path components that differ only by case (feature vs Feature).

You can file it in the official repository: 

One thing to consider mentioning: this may ultimately be a Git-on-Windows limitation rather than a bug in `actions/checkout` itself. Framing it as "checkout should detect and provide a clearer error message" may make the issue more actionable for the maintainers.