sudo just install` fails when rustup is user-installed (no root toolchain)

[ctsdownloads]

Summary

The install recipe in the justfile depends on build-release, which causes cargo build --release to re-run under sudo. On systems where rustup is installed per-user (the default for most Linux distros including CachyOS/Arch), root has no default toolchain configured, so the rebuild fails even though the user-level build succeeded moments earlier.

Steps to reproduce

1. Fresh CachyOS install with rustup installed as a normal user (rustup default stable set for the user)
2. Follow the README exactly:

   git clone https://codeberg.org/bhh32/cupola.git
   cd cupola
   sudo just install
   

Expected

Cupola builds and installs to /usr/local/bin.

Actual

cargo build --release
error: rustup could not choose a version of cargo to run, because one wasn't specified explicitly, and no default is configured.
help: run 'rustup default stable' to download the latest stable release of Rust and set it as your default toolchain.
error: Recipe `build-release` failed on line 11 with exit code 1

Root cause

In the justfile:

install: build-release
    sudo cp target/release/cupola /usr/local/bin
    sudo cp data/*.desktop /usr/share/applications
    sudo cp data/*.svg /usr/share/icons/hicolor/scalable/apps

When the whole recipe is run under sudo, the build-release dependency also runs under sudo, invoking cargo as root. Root's rustup has no default toolchain set.

Workaround

Build as user, then run the install steps manually:

just build-release
sudo cp target/release/cupola /usr/local/bin
sudo cp data/*.desktop /usr/share/applications
sudo cp data/*.svg /usr/share/icons/hicolor/scalable/apps

Suggested fix

Split the recipe so install only handles file copying, and add a separate recipe that does both. This way the user builds as themselves and only escalates for the copy step:

# Install (assumes binary is already built)
install:
    sudo cp target/release/cupola /usr/local/bin
    sudo cp data/*.desktop /usr/share/applications
    sudo cp data/*.svg /usr/share/icons/hicolor/scalable/apps

# Build and install
install-all: build-release install

And update the README to:

git clone https://codeberg.org/bhh32/cupola.git
cd cupola
just build-release
sudo just install

Environment

• OS: CachyOS (Arch-based)
• Rust: stable (installed via rustup, user-level)
• just: installed
• libxkbcommon: installed