Compiling a dependent package using branch: "main" fails due to symlinks

[rvsrvs]

Building a package which depends on:

.package(url: "https://github.com/apple/swift-atomics.git", branch: "main")

with Xcode 15 RC1 fails with the message:

the package manifest at '/Package@swift-5.8.swift' cannot be accessed (InternalError(description: "Internal error. Please file a bug at https://github.com/apple/swift-package-manager/issues with this info. symlinks not supported")) in https://github.com/apple/swift-atomics.git

Changing the symlinks for Package@swift-5.7.swift and Package@swift-5.8.swift to be actual files by copying the linked file into place resolves the problem.

Information

• Package version: Current main on 13-Sep-2023
• Platform version: MacOS Sonoma RC1
• Swift version: swift-driver version: 1.87.1 Apple Swift version 5.9 (swiftlang-5.9.0.128.108 clang-1500.0.40.1) Target: arm64-apple-macosx14.0

Checklist

• [x ] If possible, I've reproduced the issue using the main branch of this package.
• [ x] I've searched for existing reports of the same issue.

Steps to Reproduce

create a new package with the depdenency shown above. It will fail with that message

Expected behavior

It should compile successfully

Actual behavior

See above.

[lorentey]

Good catch! We'll probably want to duplicate the file contents then. (Weird that this proved an issue on macOS, of all platforms...)

[ktoso]

Let's do a naive simple fix for now to avoid symlinks.

Perhaps this can be cleaned up a bit so multiple copies would not be necessary? But to unblock development for folks here's a simple patch: #100