The output from `cargo package --list` is not good for workspaces

[torhovland]

Problem

This issue was discovered when working on #13947, but the problem is also on master.

When run in a workspace root directory, cargo package --list outputs something like this:

Cargo.lock
Cargo.toml
Cargo.toml.orig
src/main.rs
Cargo.toml
Cargo.toml.orig
src/lib.rs

It doesn't indicate that half the files are from one crate, and the other half from another crate.

The question is how to improve this in a way that is backward compatible. It is likely that the current output is used by CI/CD scripts, and should ideally stay as it is when packaging single crates.

Steps

No response

Possible Solution(s)

No response

Notes

No response

Version

cargo 1.78.0 (54d8815d0 2024-03-26)
release: 1.78.0
commit-hash: 54d8815d04fa3816edc207bbc4dd36bf18014dbc
commit-date: 2024-03-26
host: aarch64-apple-darwin
libgit2: 1.7.2 (sys:0.18.2 vendored)
libcurl: 8.4.0 (sys:0.4.72+curl-8.6.0 system ssl:(SecureTransport) LibreSSL/3.3.6)
ssl: OpenSSL 1.1.1w  11 Sep 2023
os: Mac OS 14.2.1 [64-bit]

[torhovland]

@rustbot label: +Command-package, +A-cli, +S-needs-design

[epage]

This is likely broken enough that we can change behavior. I wonder if we should just error in this case. If we had json output, then I could see specializing the list per package.

[epage]

See #11666 for json output

[torhovland]

One approach that is probably better than an error message would be this:

• In the case of one crate, keep the output as it is.
• In the case of multiple crates, output the name or full path of each crate followed by its file contents. Let each crate be separated by a blank line.

[epage]

I think a lot depends on what we consider the output intended to be. The current single-crate output is used programmatically. Extending the format with a per-crate header extends what we are offering. This is why I was looking to crate output.