Dependency Management Guidelines

This skill provides guidance for managing Rust dependencies in the Jarvy project.

Dependency Selection Criteria

Prefer Standard Library First

Before adding external crates, verify stdlib cannot handle the need:

// PREFER: stdlib for simple operations
use std::fs;
use std::path::PathBuf;
use std::process::Command;

// AVOID: Adding crates for trivial functionality

Evaluation Checklist

When considering a new dependency:

1. Necessity: Can this be implemented in <100 lines?
2. Maintenance: Is the crate actively maintained?
3. Transitive deps: How many dependencies does it bring?
4. Compile time: What is the build time impact?
5. License: Is it compatible (MIT, Apache-2.0, BSD)?

Reuse Existing Dependencies

Need	Use Existing
JSON	serde_json
YAML	serde_yaml
TOML	toml
Error types	thiserror
HTTP	ureq
Logging	tracing
CLI args	clap with derive
Interactive prompts	inquire
Unique IDs	uuid v7
Platform dirs	dirs

Feature Flag Best Practices

Minimize Enabled Features

# GOOD: Explicit minimal features
clap = { version = "4.5", features = ["derive"] }
uuid = { version = "1.10", features = ["v7"] }
serde = { version = "1.0", features = ["derive"] }
ureq = { version = "3.1", features = ["json"] }

# BAD: Enabling all features
# clap = { version = "4.5", features = ["full"] }

Document Non-Obvious Features

# v7 provides time-ordered UUIDs for telemetry event ordering
uuid = { version = "1.10", features = ["v7"] }

Disable Default Features When Appropriate

some-crate = { version = "1.0", default-features = false, features = ["needed"] }

Version Management

Version Specification

# Standard: Allow patch and minor updates
serde = "1.0"

# Specific: Pin only when necessary
opentelemetry-otlp = "0.31.0"

Update Commands

# Update all dependencies
cargo update

# Update specific dependency
cargo update -p serde

# Check for outdated dependencies
cargo outdated

Lockfile Management

• Commit Cargo.lock: This is an application, not a library
• Review lockfile changes: Check diffs for unexpected updates

Security Auditing

Automated Auditing

# Install audit tools
cargo install cargo-audit
cargo install cargo-deny

# Run security advisory check
cargo audit

# Comprehensive check (security, licenses, duplicates)
cargo deny check

cargo-deny Configuration

Create deny.toml:

[advisories]
vulnerability = "deny"
unmaintained = "warn"
yanked = "deny"

[licenses]
unlicensed = "deny"
allow = ["MIT", "Apache-2.0", "BSD-2-Clause", "BSD-3-Clause", "ISC", "Zlib"]

[bans]
multiple-versions = "warn"
wildcards = "deny"

[sources]
unknown-registry = "deny"
unknown-git = "deny"

Security Workflow

1. Pre-commit: Run cargo audit locally
2. CI Pipeline: Run cargo deny check on every PR
3. Weekly: Automated dependency update PRs
4. Release: Full audit before publishing

Adding New Dependencies

Process

1. Justify: Document why needed
2. Research: Check alternatives and maintenance status
3. Audit: Run cargo audit after adding
4. Minimize: Enable only required features
5. Test: Verify compile time impact

PR Template

## New Dependency: `crate-name`

**Purpose**: [What functionality?]

**Alternatives Considered**:
- stdlib: [Why not sufficient?]

**Metrics**:
- Transitive dependencies: [count]
- Build time impact: [minimal/moderate/significant]
- Last updated: [date]

**Features Enabled**: [list and why]

Build Optimization

Current Build Configuration

[build]
rustc-wrapper = "sccache"
jobs = 16

[profile.dev]
opt-level = 1

[profile.release]
lto = "thin"

Monitor Build Times

# Measure build time
cargo build --timings

# Generate HTML report
cargo build --timings=html

Platform-Specific Dependencies

[target.'cfg(target_os = "macos")'.dependencies]
macos-crate = "1.0"

[target.'cfg(target_os = "windows")'.dependencies]
windows-crate = "1.0"

Verify cross-platform compilation:

cargo check --target x86_64-unknown-linux-gnu
cargo check --target x86_64-apple-darwin
cargo check --target x86_64-pc-windows-msvc

Current Project Dependencies

Runtime Dependencies

Crate	Version	Purpose
clap	4.5.6	CLI parsing
serde	1.0.204	Serialization
toml	0.9.5	Config parsing
thiserror	2.0.16	Error types
tracing	0.1.40	Logging
ureq	3.1.2	HTTP client
inquire	0.9.1	Interactive prompts
dirs	6.0.0	Platform directories
uuid	1.10.0	Unique IDs
machineid-rs	1.2	Machine fingerprint

Dev Dependencies

Crate	Version	Purpose
tempfile	3.20.0	Temp file handling
assert_cmd	2.0.17	CLI testing

Dependency Checklist

1. Checked if stdlib can handle the need
2. Reviewed existing dependencies for reuse
3. Minimized enabled features
4. Ran cargo audit after adding
5. Tested cross-platform compilation
6. Documented justification in PR