actions/github-script is a GitHub Action that allows users to run JavaScript/TypeScript scripts in their workflows with access to a pre-authenticated GitHub API client and other GitHub Action toolkit packages. The action executes user-provided scripts as asynchronous functions within a context that includes github, context, core, glob, io, exec, getOctokit, and require objects. Scripts can make GitHub API calls, perform file operations, and return values that become action outputs. The architecture follows standard GitHub Action patterns with TypeScript source code compiled and bundled via ncc into a single distributable file. Key components include async-function.ts for safely executing user scripts, create-configured-getoctokit.ts for creating secondary authenticated clients with inherited configuration, and wrap-require.ts for handling module resolution. The action integrates with GitHub's retry and request-logging plugins and supports configurable retries, user-agent, base URL, and result encoding.

This repository implements the official GitHub Action `actions/setup-node`, which sets up a Node.js environment in GitHub Actions workflows. It downloads and caches the requested Node.js version (including LTS, nightly, RC, and v8-canary builds), adds it to the PATH, optionally caches npm/yarn/pnpm dependencies using `actions/cache`, registers problem matchers for TypeScript and ESLint, and configures authentication for private npm registries. The architecture is a composite action with a main entry point (`src/setup-node.ts`) and a post-job cache-save entry point (`src/cache-save.ts`), both compiled via ncc. The codebase is well-structured with abstract base classes for distribution handling, a factory pattern for selecting the correct distribution, and separate modules for cache utilities and authentication. It relies on the `@actions/*` toolkit libraries and external services (GitHub node-versions manifest, nodejs.org dist mirrors).

This repository implements a GitHub Action (`actions/setup-java`) that installs a Java JDK or JRE in CI environments. It supports 17+ distributions (Adoptium Temurin, Azul Zulu, Microsoft, Amazon Corretto, GraalVM, Liberica, etc.) and resolves versions from user input, version files (`.java-version`, `.tool-versions`, `.sdkmanrc`), or the `latest` alias. The action also sets up dependency caching for Maven, Gradle, and sbt, generates Maven settings.xml with server credentials and GPG signing profiles, and handles Maven toolchains.xml merging across workflow steps. It includes signature verification (GPG) for Temurin and Microsoft distributions and checksum verification for downloaded archives. The architecture is modular: a factory pattern lazily loads distribution-specific installer classes (each extending an abstract `JavaBase`), which handle version resolution, download, extraction, and tool-cache registration. A separate cache system (JDK binary cache, dependency cache, and resolution cache) uses GitHub Actions cache primitives with configurable retention. The codebase is written in TypeScript and heavily leverages the `@actions/*` toolkit. Tests mock all external dependencies and use static JSON fixtures to simulate vendor APIs. The action is deployed as compiled bundles in `dist/` and is actively maintained with comprehensive CI workflows for e2e testing across OS, architecture, and distribution variants. The core value of this repository is its reliability and breadth of support: it automates the brittle process of Java version management in CI, handles edge cases like early-access builds, floating version tags, and platform-specific package types (jdk+fx, jdk+jmods, etc.). The caching and retry logic reduce pipeline execution time and failure rates. While tightly integrated with GitHub Actions, several internal modules (retrying HTTP client, checksum verification, XML escaping) are isolated enough for potential extraction into other TypeScript projects.

This repository is a thin GitHub Actions composite action that serves as a wrapper around `actions/attest`. It provides a user-friendly interface for generating signed build provenance attestations for workflow artifacts, delegating all actual logic to the underlying `actions/attest` action. The action.yml defines inputs (subject-path, subject-digest, etc.) and outputs (bundle-path, attestation-id, etc.) and passes them directly to the pinned version of `actions/attest`. There is no custom code; the entire implementation is a single composite step. The CI workflow tests the action by running it with a dummy subject digest. The repository is actively maintained with dependabot and CI, but it offers no reusable components or novel engineering patterns.

This repository implements a GitHub Action (`actions/ai-inference`) that runs AI model inference inside GitHub Actions workflows by shelling out to the GitHub Copilot CLI. The action accepts a user prompt (inline or from a file), an optional system prompt, a model identifier, and various configuration options. It builds a combined prompt string, spawns the Copilot CLI with `-p`, `-s`, and `--no-ask-user` flags, captures the model's text response, and exposes it via `response` and `response-file` outputs. The architecture is a single Node.js action (bundled into `dist/index.js`) with modular TypeScript source files: `main.ts` orchestrates input parsing and provider dispatch, `copilot.ts` handles CLI invocation and error handling, `prompt.ts` provides structured `.prompt.yml` file parsing with template variable substitution, and `helpers.ts` contains utility functions. The action is tightly coupled to the Copilot CLI, which must be pre-installed and authenticated on the runner. It supports only the `copilot` provider. The codebase is well-structured, includes unit tests, and follows modern TypeScript practices.

The `actions/upload-pages-artifact` repository provides a composite GitHub Action that packages a directory of static assets into a tarball and uploads it as an Actions artifact, specifically for deploying to GitHub Pages. The action is defined in `action.yml`, which orchestrates shell commands to create a tar archive with proper handling of symlinks (dereferencing them), exclusion of `.git` and `.github` directories, and optional exclusion of hidden files. The archive is then uploaded using the `actions/upload-artifact` action. The action runs on Linux, macOS, and Windows runners, with platform-specific adjustments (e.g., using `gtar` on macOS). The repository also includes a test script (`script/new-artifact.sh`) to generate sample files for testing, along with a comprehensive CI matrix that validates the action on all three OSes and checks for correct handling of hidden files and symlinks. Overall, this is a focused, well-maintained utility action that solves a specific problem (preparing Pages artifacts) with robust cross-platform support.