cargo vendor doesn't respect symbolic links

[pcwalton]

Problem

The function that cargo vendor uses to copy files doesn't respect symbolic links: https://github.com/rust-lang/cargo/blob/master/src/cargo/ops/vendor.rs#L354

This causes cargo vendor to fail if there are any broken symbolic links in the crate it's trying to vendor.

Steps

$ cargo new blahblah
$ cd blahblah
$ echo 'rsdd = { git = "https://github.com/SHoltzen/rsdd", rev = "28ba18d3" }' >> Cargo.toml
$ cargo vendor test

Possible Solution(s)

Make that function respect symbolic links.

Notes

No response

Version

cargo 1.57.0-nightly (d56b42c54 2021-09-27)
release: 1.57.0
commit-hash: d56b42c549dbb7e7d0f712c51b39400260d114d4
commit-date: 2021-09-27

[jmintb]

Can I have a crack at this?

[Muscraft]

I would hold off on working on this as we are looking into a fix for #11192 and it may resolve this issue as well.