Cargo incorrectly detects a package name conflict when a workspace package has the same name as a (transitive) dependency

[avsaase]

Problem

Take a project directory structure like this:

.
├── Cargo.lock
├── Cargo.toml
├── examples
│   └── grid
│       ├── Cargo.toml
│       └── src
│           └── main.rs
└── src
    └── lib.rs

Cargo.toml:

[package]
name = "library"
version = "0.1.0"
edition = "2021"

[dependencies]
taffy = { version = "0.3.16", features = ["grid"] }

[workspace]
members = ["examples/grid"]

examples/grid/Cargo.toml:

[package]
name = "grid"
version = "0.1.0"

[dependencies]
library = { path = "../../" }

Dependency tree:

library v0.1.0 ([omitted])
└── taffy v0.3.16
    ├── arrayvec v0.7.4
    ├── grid v0.10.0
    ├── num-traits v0.2.17
    │   [build-dependencies]
    │   └── autocfg v1.1.0
    └── slotmap v1.0.6
        [build-dependencies]
        └── version_check v0.9.4

When you try to run the grid example with cargo run --package grid you get an error:

error: There are multiple `grid` packages in your project, and the specification `grid` is ambiguous.
Please re-run this command with `-p <spec>` where `<spec>` is one of the following:
  [email protected]
  [email protected]

Steps

1. Checkout https://github.com/avsaase/cargo-ambiguous-package
2. Run cargo run --package grid
3. Run cargo run --package [email protected]

Possible Solution(s)

The problem seems to be that cargo sees the transitive grid dependency of taffy and sees that as a conflict with the package of the same name in the local workspace. This must be a bug because there is no reason to run a binary target from a (transitive) dependency with cargo run. And even if there was, the grid crate doesn't have a binary target so there's nothing to run.

The solution suggested by cargo is also not correct because running cargo run -p [email protected] gives the error that the package is not found in the workspace.

A workaround is to use globally unique package names in workspaces but this is very restrictive because adding a dependency can easily create a new conflict.

Notes

No response

Version

cargo 1.73.0 (9c4383fb5 2023-08-26)
release: 1.73.0
commit-hash: 9c4383fb55986096b414d98125421ab87b5fd642
commit-date: 2023-08-26
host: x86_64-unknown-linux-gnu
libgit2: 1.6.4 (sys:0.17.2 vendored)
libcurl: 8.2.1-DEV (sys:0.4.65+curl-8.2.1 vendored ssl:OpenSSL/1.1.1u)
ssl: OpenSSL 1.1.1u  30 May 2023
os: Linux 16 (focal) [64-bit]