Julia Package Dev

Julia Package Development

Use this skill for package-oriented Julia work: bootstrapping a package, local environments, multi-package workspaces, extensions, and Pkg apps.

Core Workflow

using Pkg

Pkg.activate("./dev")
Pkg.develop(path="./MyPackage.jl")
using MyPackage

Prefer environments over mutating the global default environment.

• Set ENV["JULIA_PKG_SERVER_REGISTRY_PREFERENCE"] = "eager" before Pkg

operations in local or CI sessions in this workspace. Use this by default when recent registrations may matter; otherwise just-registered packages can appear to be missing and create false resolution failures.

• Prefer Pkg.test(...) over directly executing test/runtests.jl when

validating a package checkout. Treat direct test/runtests.jl execution as a runner-debugging path, not the default validation path.

• For test-only dependencies, use test/Project.toml with root

[workspace] projects = ["test"]; avoid new [extras]/[targets] test declarations except for legacy compatibility.

• Never read or edit Manifest.toml directly. Treat every manifest as

generated state owned by Pkg.

• If dependency resolution behaves impossibly, run Pkg.update() and

Pkg.resolve() in the relevant environment first. If recurrent issues remain, delete the relevant Manifest.toml file and regenerate it with Pkg.instantiate().

• Read Project.toml when needed, but change dependencies and compat entries

only through Pkg APIs such as Pkg.add, Pkg.develop, Pkg.rm, Pkg.free, and Pkg.compat.

Multi-Repo Rule

• In a workspace with sibling repos, if compat or registry resolution blocks

testing, first Pkg.develop(path=...) the local dependency checkouts already present, preferably on their current master/main.

• Do this before chasing registry lag or editing compat blindly.

Pick a Topic

• Pkg commands and dependency management:

references/pkg-commands.md

• Interactive debugging and exploration:

references/debugging.md

• Multi-package development and release flow:

references/multipackage-git-workflow.md

• Package extension patterns:

references/extension-patterns.md

• Testing and documenting extensions:

references/extension-testing.md

• User-facing extension error hints:

references/weakdephelpers.md

• Pkg app scaffolding and CLI patterns:

references/pkg-app-patterns.md

Common Tasks

Shared Workspace

using Pkg
Pkg.activate("quantum-dev")
Pkg.develop(path="./QuantumInterface.jl")
Pkg.develop(path="./QuantumSavory.jl")

Notes

• Use julia-tests for test execution and organization.
• Use julia-docs for docs setup and doctests.
• Use julia-comonicon when you need a richer CLI than Pkg apps provide.

Related Skills

• julia-tests
• julia-docs
• julia-scratch

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Krastanov
• Source: Krastanov/JuliaLLMAgentSkills
• License: Unlicense

Install and usage instructions live in the source repository linked above.