cargo list does not de-duplicate entries

[jonhoo]

On Arch Linux, among other distros, /bin is a symlink to /usr/bin. This makes cargo list show many components twice:

$ which -a cargo-clippy
/usr/bin/cargo-clippy
/bin/cargo-clippy
$ cargo list | grep clippy
    clippy
    clippy

It's a little unclear how to fix this though, since cargo would have to know that those two binaries are indeed the same. Resolving symlinks with readlink before de-duplicating here might be the way to go? Alternatively, maybe the list should be de-duplicated based only on the command name, and not on the full path as well. That is, make that BTreeSet a BTreeMap with name as the key. We'd still then have to resolve conflicts, but have to do that today anyway!

As an aside to this, it'd be great if cargo list showed the path of the command it'll use to execute a given component by default. This happens if --verbose is passed currently, but I'm not sure I see the reason to hide it in non-verbose output, given that the command descriptions for built-ins are always shown?

[jonhoo]

cc @akshayknarayan

[ehuss]

Note: This often happens on Windows, where rustup adds the toolchain bin directory to PATH (for DLL loading).

This should be a relatively simple fix, to use a BTreeMap instead of a BTreeSet here.

[0xPoe]

@rustbot claim

[nipunn1313]

@rustbot claim

Sorry @hi-rustin - I think I just raced with you - I had just coded this one up. Perhaps you can review #9773 ?