I have a new python project set up using uv workspaces.

This means I have a repo that looks something like this:

.
├── core
│   ├── pyproject.toml
│   ├── src
│   └── uv.lock
├── mcp_server
│   ├── pyproject.toml
│   └── src
├── pyproject.toml
├── README.md
├── shared
│   ├── pyproject.toml
│   └── src
└── uv.lock

This works fine locally, but with Railway the build command it uses needs to be changed to support the workspace. With the default:

uv sync --locked --no-dev --no-install-project 

We get the error:

The lockfile at `uv.lock` needs to be updated, but `--locked` was provided. To update the lockfile, run `uv lock`.

I believe this is because it is not installing the dependencies for all packages and so it is a changed list. In theory we could change the build command, but that doesn't seem to be working for me? i.e. I've tried changing the "Custom build command" to this, but it seems to be complete ignored.

Has anyone got this working?