With package selection, --package <non-existent> --workspace doesn't warn or error

[sunshowers]

Problem

Originally reported as nextest-rs/nextest#1108.

With Cargo's package selection, this errors out:

$ cargo build --package non-existent
error: package ID specification `non-existent` did not match any packages

However, this does not error out:

$ cargo build --package non-existent --workspace
<build occurs...>

I think this should at least produce a warning and maybe eventually error out.

(I tried searching for issues a bit but I couldn't figure out the right keywords.)

Steps

As above.

Possible Solution(s)

Produce a warning on --workspace and -p <non-existent>. Maybe eventually turn it into an error

Notes

No response

Version

% cargo +nightly version --verbose           
cargo 1.76.0-nightly (6790a5127 2023-11-10)
release: 1.76.0-nightly
commit-hash: 6790a5127895debec95c24aefaeb18e059270df3
commit-date: 2023-11-10
host: x86_64-unknown-linux-gnu
libgit2: 1.7.1 (sys:0.18.1 vendored)
libcurl: 8.4.0-DEV (sys:0.4.68+curl-8.4.0 vendored ssl:OpenSSL/1.1.1u)
ssl: OpenSSL 1.1.1u  30 May 2023
os: Pop!_OS 22.04 (jammy) [64-bit]

[766974616c79]

@rustbot claim

[progressive-galib]

@weihanglo looks like #14755 doesnt fix it, i can pick it up

[linyihai]

This below is a test snapshot for current behavior, Cargo will ignore the --pacakge flags due to it prefers the workspace option

    p.cargo("check --package baz --workspace")
        .with_stderr_data(str![[r#"
[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s

"#]])
        .run();

    p.cargo("check --package nonexistence --workspace")
        .with_stderr_data(str![[r#"
[CHECKING] baz v0.1.0 ([ROOT]/foo/baz)
[CHECKING] foo v0.1.0 ([ROOT]/foo)
[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s

"#]])
        .run();

IMO, If --package and --workspace both were specified, In this case, warn --package nonexistence will be ignored much better than warn --package nonexistence didn't match.

[epage]

IMO, If --package and --workspace both were specified, In this case, warn --package nonexistence will be ignored much better than warn --package nonexistence didn't match.

I disagree. The warning would only be about the --package being redundant. The user expressed an intent with --package nonexistent and we should warn, or even error, if that intent was not satisfied.

For myself, I feel like non-existent packages should probably be an error, rather than a warning,. That would be a change in behavior but I think we can chalk it up to a bug. If we feel a transition period is needed, we could start as a warning.

[linyihai]

The user expressed an intent with --package nonexistent and we should warn, or even error, if that intent was not satisfied.

Yes I agree it.

The warning would only be about the --package being redundant.

IMO, I think it would be good to also add this warning -workspace will be selected and ignored -package if they passed in the same time. Or we could add this description in somewhere (Cargo book or the --help).

[epage]

Yes I agree it.

What are your thoughts on error vs warn?

IMO, I think it would be good to also add this warning -workspace will be selected and ignored -package if they passed in the same time. Or we could add this description in somewhere (Cargo book or the --help).

I'd prefer to discuss changes like that separate from this so we don't get bogged down in details from the other.

[linyihai]

What are your thoughts on error vs warn?

My assumption that --package nonexistence --workspace this case will be very rare, it looks like a hard error is fine to me.

But given that this situation was introduced from the start, we can start with warn first.

[epage]

@linyihai we talked about this in the Cargo team meeting today and felt there is not likely enough of an impact of fixing this CLI bug to have a gradual transition, preferring instead to make this an error from the beginning.

[linyihai]

That makes sense. I had updated the PR to make this an error