1. History¶

The Rust programming language was initiated as a personal project by Mozilla researcher Graydon Hoare. After realizing its potential for efficient safety and performance, the software company started sponsoring its development and launched it in 2010. It was in that year that the Rust compiler, rustc, in the form it is used today, was launched. From 2010 to 2015, Rust underwent many iterations and experimentation up until the release of Rust 1.0 (May 2015), which also established the first form of independent governance for the project.

Rust continues to be a highly iterative language, with a new stable release every six weeks. It follows the “release trains” model (also used in web browsers), with changes landing on the nightly builds first, then becoming available in the beta release for six weeks, and finally reaching a stable state.

When developing new features, Rust favors an “open” philosophy, making changes available as soon as possible on the nightly builds behind experimental feature flags. This allows users to test and provide feedback on new and experimental features before their design and implementation is fully finalized, increasing the confidence when those features are then stabilized.

From the beginning, Rust has emphasized performance, type safety, and concurrency as a memory-safe language. Rust also focuses on the developer experience, by providing great tooling around the language (such as the “cargo” build system, the “rustdoc” documentation generator, the “Clippy” linter, and the “Rust Analyzer” IDE plugin) and leading the industry in the quality and usefulness of its compiler errors and warnings.

Today, the Rust project has an independent governance structure composed of many teams, with both volunteers and corporate contributors leading the programming language and its development. In 2021, the Rust project created the Rust Foundation, a non-profit organization “dedicated to stewarding the Rust programming language, nurturing the Rust ecosystem, and supporting the set of maintainers governing and developing the project”. The Rust Foundation does not make technical, language or governance decisions: it has a support role for the project, providing crucial funding, employment of key roles, and legal support.

“Ferrocene”, started in 2021 after years of planning, is a qualified Rust compiler with a focus on the ISO 26262 standard for the automotive industry. It is maintained by Ferrous Systems, which also qualifies new versions of the Rust compiler, as required in safety and mission-critical settings.

1.2. Upstream Release Schedule¶

The upstream releases follow a software release train model, with three release channels: nightly, beta, and stable.

All upstream development is done on the master branch of the upstream GitHub repository. Every night, the upstream release infrastructure takes the latest commit on the master branch and produces a nightly release.

Once a stable release takes place, the upstream release infrastructure promotes the nightly release of that day to beta release on a beta branch. When a bug or a regression is fixed, the associated commit is merged into the master branch, and also backported into the beta branch to produce a new beta release.

Every six weeks, the upstream release infrastructure promotes the last beta release to a stable release on a stable branch. The stable branch is on a fixed schedule, so developers are always aware of when the next release will be available for download.

The following diagram shows how the Upstream release trains work: