Rust Backend

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The Rust backend provides build orchestration for Rust projects using Cargo.

Detection

The Rust backend is detected when a Cargo.toml file is present in the project directory.

Configuration

Configure the Rust backend via fish.toml in your project or workspace root:

[build]
backend = "rust"
jobs = 8
no_cache = false
semantic = true
critical_path = true

[pipelines.build]
inputs = ["src/**/*", "Cargo.toml", "Cargo.lock"]
outputs = ["target/release/**/*"]

[pipelines.test]
depends_on = ["build"]
inputs = ["tests/**/*", "src/**/*"]

Tasks Generated

Build Task

cargo build --release --features <features>

Test Task

cargo test --release --features <features>

Check Task

cargo check --release --features <features>

Doc Task

cargo doc --release --features <features>

Dependency Extraction

The Rust backend extracts dependencies from:

• Cargo.toml dependencies section
• Cargo.lock for exact versions
• Workspace dependencies

Fingerprinting

The Rust backend fingerprints:

• Cargo.toml content
• Cargo.lock content
• Source files (excluding target/)
• Build configuration

Examples

Basic Rust Project

cd my-rust-project
fish build

Workspace with Features

cd my-workspace
fish build -p my-package --features "serde,uuid"

Workspace with Tests

cd my-workspace
fish test

Limitations

• Requires Rust toolchain installed
• Cargo workspaces supported
• Custom build scripts supported via procedural macros

Performance Optimization

The Rust backend uses:

• Level batching: Groups independent packages
• Feature-aware caching: Cache per feature combination
• Workspace-aware: Optimizes for workspace builds

Troubleshooting

Cargo not found

Install Rust: curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Build fails with linking errors

Check that native dependencies are installed and toolchain is correct.

Cache not working

Clear cache: Fish cache prune and rebuild.