fix(toml): Error on [project] in Edition 2024

[epage]

What does this PR try to resolve?

[package] was added in 86b2a2a in the pre-1.0 days but [project] was never removed nor did we warn on its use until recently in #11135. So likely we can't remove it completely but we can remove it in Edition 2024+.

This includes cargo fix support which is hard coded directly into the cargo fix command.

This is part of

• Next step for deprecations in Cargo #13629
• Tracking Issue for Rust 2024: Cargo deprecations rust#123754

While we haven't signed off on everything in #13629, I figured this (and a couple other changes) are not very controversial.

How should we test and review this PR?

Per commit. Tests are added to show the behavior changes, including in cargo fix.

Additional information

[rustbot]

r? @weihanglo

rustbot has assigned @weihanglo.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[weihanglo]

This only errors out on edition 2024, though for hard errors it's better to get a consensus from the team.

@rfcbot fcp merge

[rfcbot]

Team member @weihanglo has proposed to merge this. The next step is review by the rest of the tagged team members:

• @Eh2406
• @Muscraft
• @arlosi
• @ehuss
• @epage
• @joshtriplett
• @weihanglo

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

[rfcbot]

🔔 This is now entering its final comment period, as per the review above. 🔔

[bors]

☔ The latest upstream changes (presumably #13754) made this pull request unmergeable. Please resolve the merge conflicts.

[weihanglo]

The cargo team went to the proposed deprecations in #13629 today, and we are fine with this erroring on Edition 2024. No need to wait for a full FCP.

@bors r+

[bors]

📌 Commit cbd9def has been approved by weihanglo

It is now in the queue for this repository.

[bors]

⌛ Testing commit cbd9def with merge 6f06fe9...

[bors]

☀️ Test successful - checks-actions
Approved by: weihanglo
Pushing 6f06fe9 to master...

[heisen-li]

Sorry, there seems to be some problem here, it doesn't fetch all members of the workspace. If the members contain [project], then cargo fix --edition won't complete the migration either.

Is this intentional, or am I misinterpreting?

[epage]

We do filter by the --package flag which is us just doing what the user told us. I'm not seeing how presence of [proiject] causes a problem. We also have a test showing that it works.

[heisen-li]

Sorry, I don't seem to have been clear.

What I meant was that if the members in the workspace use [project] instead of [package], then executing the command cargo fix --edition in the workspace does not modify the members.

I'm wondering if the changes should be done on all members at once.

[epage]

I think I'm still missing the problem case.

Could you create a test case to demonstrate it?

[heisen-li]

If there is a workspace ws containing the member hello.

which:

# [ws]/Cargo.toml
[workspace]
members = ["hello"]

[project]     # Pay attention here 
name = "ws"
version = "0.1.0"
edition = "2021"

# [ws]/hello/Cargo.toml
[project]     # Pay attention here 
name = "hello"
version = "0.1.0"
edition = "2021"

After running cargo fix --edition --allow-no-vcs in the workspace. The cargo.toml of ws completes the modification, but the cargo.toml of member hello does not.

I think both should be modified to [package] here.

[epage]

I've written that up as a test case which is passing.

Yes, we aren't migrating hello's Cargo.toml but we also aren't migrating hellos src/lib.rs. Manifest and rust migration should be done hand-in-hand. The user has to opt-in to migrating hello with the --workspace flag. cargo fix --edition --workspace will migrate both packages, manifest and rust.

#[cargo_test]
fn migrate_project_to_package_ws() {
    let p = project()
        .file(
            "Cargo.toml",
            r#"
cargo-features = ["edition2024"]

[workspace]
members = ["hello"]

# Before project
[ project ] # After project header
# After project header line
name = "foo"
edition = "2021"
# After project table
"#,
        )
        .file("src/lib.rs", "")
        .file(
            "hello/Cargo.toml",
            r#"
cargo-features = ["edition2024"]

# Before project
[ project ] # After project header
# After project header line
name = "hello"
edition = "2021"
# After project table
"#,
        )
        .file("hello/src/lib.rs", "")
        .build();

    p.cargo("fix --edition --allow-no-vcs")
        .masquerade_as_nightly_cargo(&["edition2024"])
        .with_stderr(
            "\
[MIGRATING] Cargo.toml from 2021 edition to 2024
[FIXED] Cargo.toml (1 fix)
[WARNING] [CWD]/hello/Cargo.toml: `[project]` is deprecated in favor of `[package]`
[LOCKING] 2 packages to latest compatible versions
[CHECKING] foo v0.0.0 ([CWD])
[MIGRATING] src/lib.rs from 2021 edition to 2024
[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [..]s
",
        )
        .run();
    assert_eq!(
        p.read_file("Cargo.toml"),
        r#"
cargo-features = ["edition2024"]

[workspace]
members = ["hello"]

# Before project
[ package ] # After project header
# After project header line
name = "foo"
edition = "2021"
# After project table
"#
    );
    assert_eq!(
        p.read_file("hello/Cargo.toml"),
        r#"
cargo-features = ["edition2024"]

# Before project
[ project ] # After project header
# After project header line
name = "hello"
edition = "2021"
# After project table
"#
    );
}