`cargo tree -d` with multitarget configured shows duplicate dependencies once per target

[joshtriplett]

Problem

With multiple targets configured in .cargo/config.toml, cargo tree -d will show each duplicated dependency once per target per version. For instance, with two targets configured, cargo tree -d will show each duplicated dependency twice per version of that dependency. It should show each version of the dependency only once.

Steps

1. Make sure you have the x86_64-unknown-linux-musl and aarch64-unknown-linux-musl targets installed.
2. Check out rust-lang/cargo at commit 64e46b0 . (Note that the reproducibility of this issue may change if new package versions become available, but the issue still exists.)
3. Run cargo tree -d; you should see this:

hex v0.3.2
└── crypto-hash v0.3.4
    └── cargo-util v0.2.2 (/path/to/cargo/crates/cargo-util)
        ├── cargo v0.68.0 (/path/to/cargo)
        └── cargo-test-support v0.1.0 (/path/to/cargo/crates/cargo-test-support)
            [dev-dependencies]
            └── cargo v0.68.0 (/path/to/cargo)

hex v0.4.3
├── cargo v0.68.0 (/path/to/cargo)
└── cargo-util v0.2.2 (/path/to/cargo/crates/cargo-util) (*)

4. Run cargo tree -d --target x86_64-unknown-linux-musl --target aarch64-unknown-linux-musl. Or, as is more likely to occur in practice, put that in .cargo/config.toml (mkdir .cargo && echo 'build.target = ["x86_64-unknown-linux-musl", "aarch64-unknown-linux-musl"]' > .cargo/config.toml) and then run cargo tree -d. You'll see this:

hex v0.3.2
└── crypto-hash v0.3.4
    └── cargo-util v0.2.2 (/path/to/cargo/crates/cargo-util)
        ├── cargo v0.68.0 (/path/to/cargo)
        └── cargo-test-support v0.1.0 (/path/to/cargo/crates/cargo-test-support)
            [dev-dependencies]
            └── cargo v0.68.0 (/path/to/cargo)

hex v0.3.2
└── crypto-hash v0.3.4
    └── cargo-util v0.2.2 (/path/to/cargo/crates/cargo-util)
        ├── cargo v0.68.0 (/path/to/cargo)
        └── cargo-test-support v0.1.0 (/path/to/cargo/crates/cargo-test-support)
            [dev-dependencies]
            └── cargo v0.68.0 (/path/to/cargo)

hex v0.4.3
├── cargo v0.68.0 (/path/to/cargo)
└── cargo-util v0.2.2 (/path/to/cargo/crates/cargo-util) (*)

hex v0.4.3
├── cargo v0.68.0 (/path/to/cargo)
└── cargo-util v0.2.2 (/path/to/cargo/crates/cargo-util) (*)

libz-sys v1.1.5
└── flate2 v1.0.22
    [build-dependencies]
    ├── cargo v0.68.0 (/path/to/cargo)
    └── cargo v0.68.0 (/path/to/cargo)

libz-sys v1.1.5
├── curl-sys v0.4.59+curl-7.86.0
│   ├── cargo v0.68.0 (/path/to/cargo)
│   └── curl v0.4.44
│       ├── cargo v0.68.0 (/path/to/cargo)
│       ├── crates-io v0.34.0 (/path/to/cargo/crates/crates-io)
│       │   ├── cargo v0.68.0 (/path/to/cargo)
│       │   └── cargo-test-support v0.1.0 (/path/to/cargo/crates/cargo-test-support) (*)
│       └── git2-curl v0.16.0
│           └── cargo v0.68.0 (/path/to/cargo)
├── flate2 v1.0.22
│   ├── cargo v0.68.0 (/path/to/cargo)
│   └── cargo-test-support v0.1.0 (/path/to/cargo/crates/cargo-test-support) (*)
├── libgit2-sys v0.14.0+1.5.0
│   ├── cargo v0.68.0 (/path/to/cargo)
│   └── git2 v0.15.0
│       ├── cargo v0.68.0 (/path/to/cargo)
│       ├── cargo-test-support v0.1.0 (/path/to/cargo/crates/cargo-test-support) (*)
│       └── git2-curl v0.16.0 (*)
└── libssh2-sys v0.2.23
    └── libgit2-sys v0.14.0+1.5.0 (*)

libz-sys v1.1.5
├── curl-sys v0.4.59+curl-7.86.0
│   ├── cargo v0.68.0 (/path/to/cargo)
│   └── curl v0.4.44
│       ├── cargo v0.68.0 (/path/to/cargo)
│       ├── crates-io v0.34.0 (/path/to/cargo/crates/crates-io)
│       │   ├── cargo v0.68.0 (/path/to/cargo)
│       │   └── cargo-test-support v0.1.0 (/path/to/cargo/crates/cargo-test-support) (*)
│       └── git2-curl v0.16.0
│           └── cargo v0.68.0 (/path/to/cargo)
├── flate2 v1.0.22
│   ├── cargo v0.68.0 (/path/to/cargo)
│   └── cargo-test-support v0.1.0 (/path/to/cargo/crates/cargo-test-support) (*)
├── libgit2-sys v0.14.0+1.5.0
│   ├── cargo v0.68.0 (/path/to/cargo)
│   └── git2 v0.15.0
│       ├── cargo v0.68.0 (/path/to/cargo)
│       ├── cargo-test-support v0.1.0 (/path/to/cargo/crates/cargo-test-support) (*)
│       └── git2-curl v0.16.0 (*)
└── libssh2-sys v0.2.23
    └── libgit2-sys v0.14.0+1.5.0 (*)

Possible Solution(s)

No response

Notes

No response

Version

cargo 1.65.0 (4bc8f24d3 2022-10-20)
release: 1.65.0
commit-hash: 4bc8f24d3e899462e43621aab981f6383a370365
commit-date: 2022-10-20
host: x86_64-unknown-linux-gnu
libgit2: 1.5.0 (sys:0.15.0 vendored)
libcurl: 7.83.1-DEV (sys:0.4.55+curl-7.83.1 vendored ssl:OpenSSL/1.1.1q)
os: Debian n/a (bookworm) [64-bit]

[weihanglo]

Not only cargo tree -d. Plain cargo tree with two or more --targets suffers from this as well.

Have two options here off the top of my head:

• Merge multiple targets to one graph. Just like what --target all does.
• Has a header to indicate what target the graph is for.

I lean towards merging them all without showing target platform infos. The user can always specify a single --target to see what happen if they want to narrow down the result.

[joshtriplett]

@weihanglo I agree; merging them seems like the right answer.