Generated source distribution does not handle aliased dependencies correctly

[0xbe7a]

Bug Description

maturin sdist does not handle "aliased" dependencies of workspaces correctly:

I have a package py_adder which is the only member of a workspace (Link to a repository containing the full minimal reproducible example is at the end).
The workspaces Cargo.toml looks like this:

[workspace]
members = [
  "py-adder"
]

[workspace.dependencies.backend]
package = "adder_backend"
version = "0.1.0"
path = "adder_backend"

adder_backend is just a minimal library containing a single function add.

adder_backends Cargo.toml looks like this:

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

My package py-adder uses this backend like this:

[dependencies]
backend = { workspace = true }

When running maturin build or maturin develop inside the py-adder folder everything works as expected and the functions can be used by python.

We can also build the source distribution by running maturin sdist inside the py-adder folder.

However, when trying to run maturin build inside the extracted source distribution folder we get:

error: no matching package named `backend` found
location searched: /private/tmp/source_code/adder-0.1.0/local_dependencies/backend
required by package `adder v0.1.0 (/private/tmp/source_code/adder-0.1.0)`
💥 maturin failed
  Caused by: Cargo metadata failed. Does your crate compile with `cargo build`?
  Caused by: `cargo metadata` exited with an error:

Which is expected, as the Cargo.toml inside folder local_dependencies/backend declares a package called adder_backend and we are looking for backend.

We recently hit this bug in polars pola-rs/polars#11371.

I compiled a repository containing a minimal reproducible example: https://github.com/0xbe7a/maturin-dependeny-rename-mre

Your maturin version (maturin --version)

maturin 1.2.3

Your Python version (python -V)

Python 3.11.5

Your pip version (pip -V)

pip 23.2.1

What bindings you're using

pyo3

Does cargo build work?

• Yes, it works

If on windows, have you checked that you aren't accidentally using unix path (those with the forward slash /)?

• Yes

Steps to Reproduce

1. Clone https://github.com/0xbe7a/maturin-dependeny-rename-mre
2. cd py-adder
3. Run maturin develop and observe that everything works as expected
4. Run maturin sdist
5. Extract the source distribution into a new folder
6. Run maturin build inside the new folder containing the extracted source

[messense]

Thanks for the report, can you try matruin main branch to see whether #1741 has fixed it already?

[0xbe7a]

Using maturin from main also produces a non-compileable source distribution.

➜  adder-0.1.0 tree
.
├── PKG-INFO
├── adder_backend
│   ├── Cargo.toml
│   └── src
│       └── lib.rs
├── py-adder
│   ├── Cargo.lock
│   ├── Cargo.toml
│   └── src
│       └── lib.rs
└── pyproject.toml

5 directories, 7 files
➜  adder-0.1.0 cat py-adder/Cargo.toml 
[package]
name = "adder"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[lib]
name = "adder"
# "cdylib" is necessary to produce a shared library for Python to import from.
crate-type = ["cdylib"]

[dependencies]
backend = { workspace = true }

[dependencies.pyo3]
version = "0.18.0"
features = ["abi3-py37"]
➜  adder-0.1.0 cat adder_backend/Cargo.toml 
[package]
name = "adder_backend"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
➜  adder-0.1.0 maturin build
error: failed to parse manifest at `/private/tmp/source_code/adder-0.1.0/py-adder/Cargo.toml`

Caused by:
  error inheriting `backend` from workspace root manifest's `workspace.dependencies.backend`

Caused by:
  failed to find a workspace root
💥 maturin failed
  Caused by: Cargo metadata failed. Does your crate compile with `cargo build`?
  Caused by: `cargo metadata` exited with an error: 
➜  adder-0.1.0

[messense]

For your repro, if you remove py-adder/Cargo.lock it should work? I'm not sure why/how you created that file in the first place, the canonical lock file for the workspace should be the top level Cargo.lock.

[0xbe7a]

In polars the equivalent of py-adder was not part of the workspace, however while minimizing the example i realized that this is not required to trigger the behaviour.

Here is the commit where i moved py-adder into the workspace 0xbe7a/maturin-dependeny-rename-mre@bcd5b48

When i remove py-adders invalid Cargo.lock the latest maturin from main works perfectly 😄, 1.2.3 is still broken !

Would you mind releasing the new sdist implementation?

[messense]

Would you mind releasing the new sdist implementation?

I'll probably release a new version next week.