cp: expand target path before checking

[WindSoilder]

Description

Fixes: #11683

User-Facing Changes

NaN

Tests + Formatting

I don't think we need to add a test, or else it'll copy some file to user's directory, it seems bad.
Done.

After Submitting

NaN

[bew]

I don't think we need to add a test, or else it'll copy some file to user's directory, it seems bad.

To write a test you could set $env.HOME to a test folder so actual user home isn't targeted?

[WindSoilder]

Thanks for your suggestion! Sadly I don't think it works. Because expand_path_with reads home dir from dirs_next::home_dir(), it doesn't know anything about $env.HOME

[bew]

Well in the end getting the home dir will look for the HOME env var (at least on Linux), so it should be possible to to set that env var before running the tests to ensure it doesn't leak into the test environment

https://doc.rust-lang.org/std/env/fn.home_dir.html

[WindSoilder]

Thanks! I've add a test on unix like system