Invoking `x` from a parent directory fails when CDPATH is set

[RalfJung]

Summary

Invoking x from a different directory does not (always) work as expected

Command used

git clone https://github.com/rust-lang/rust
rust/x check miri

This prints:

/usr/bin/python3: can't open file '/home/r/src/rust/tmp/rust\n/home/r/src/rust/tmp/rust/x.py': [Errno 2] No such file or directory

I don't know what's happening here but the literal \n in that string makes me think some escaping went wrong somewhere.

HEAD

2f4dfc7

[Kobzol]

We have the src/tools/x binary, which is designed to allow executing x from any subdirectory of a rustc checkout. The command that you posted works for me locally though.

[RalfJung]

Ah I think I see the problem:

realpath() {
    local path="$1"
    if [ -L "$path" ]; then
        readlink -f "$path"
    elif [ -d "$path" ]; then
        (cd -P "$path" && pwd)
    else
        echo "$(realpath "$(dirname "$path")")/$(basename "$path")"
    fi
}

The second case here, cd -P "$path" && pwd seems to assume that cd is silent. However, I have CDPATH set up on my system and that makes cd print the directory it cds to.

[Kobzol]

If you know an easy way of fixing that, while making sure that it also works for the case when cd is indeed silent, I'm happy to review a PR. Otherwise I'd just move this to the "too weird of a setup for bootstrap" pile and close the issue.