Repositories

A repository is a storage location for software artifacts, files, and their revision history. In software development, a source code repository stores a project's files along with the complete history of changes, enabling collaboration, auditing, and rollback. Repositories are typically managed by version control systems and may exist locally on a developer's machine or remotely on servers or cloud services.

There are different repository models. Centralized version control systems maintain a single shared repository that all contributors synchronize with. Distributed version control systems allow every contributor to have a full copy of the repository, enabling offline work and peer-to-peer collaboration. Examples include centralized tools such as Subversion and Perforce, and distributed ones such as Git and Mercurial. Repositories may be public or private, and access is controlled by permissions.

A repository's structure includes commits, branches, and tags, along with metadata such as authors, timestamps, and messages. In distributed systems, the commit graph records the history and relationships between changes. Common operations include cloning or fetching to obtain a copy, pulling to integrate remote changes, pushing to publish local changes, and merging branches. Workflows often use pull requests or merge requests to review changes before integration.

Beyond source code, repositories can also host build artifacts, libraries, and dependencies in package registries or artifact repositories, as well as container images in container registries. Repositories support workflows such as continuous integration, access controls, hooks, and auditing to enforce policies, licensing, and reproducibility.

In practice, repositories enable collaboration, version history, traceability, and reproducible builds, forming a core component of modern software development and deployment pipelines.