Apple is open-sourcing Swift Build, the build system used to create Swift itself and related projects. This move aims to improve build performance, enable more seamless integration with other build systems, and foster community involvement in its evolution. The open-sourcing effort will happen gradually, focusing initially on the build system's core components, including the build planning framework and the driver responsible for invoking build tools. Future plans include exploring alternative build executors and potentially supporting other languages beyond Swift. This change is expected to increase transparency, encourage broader adoption, and facilitate the development of new tools and integrations by the community.
The Swift community has announced a significant advancement in the evolution of its build system: the open sourcing of Swift Build. This marks a pivotal moment, transitioning the system from a closed-source component tightly coupled with the Swift compiler to a standalone, community-driven project. The blog post meticulously outlines the motivations and benefits of this transition, as well as the technical details of the new architecture.
Historically, the build system responsible for compiling Swift projects was integrated directly into the Swift compiler. While this approach offered certain advantages in the early stages of Swift's development, it presented increasing challenges as the language and its ecosystem matured. The monolithic nature of the compiler-integrated build system made it difficult to iterate rapidly on build features independently of the compiler itself. Furthermore, it hampered the ability of external developers and tool authors to contribute to the build system's evolution or adapt it to their specific needs.
The newly open-sourced Swift Build addresses these limitations by introducing a modular and extensible architecture. It is designed to be language-agnostic, capable of building projects written in C, C++, Objective-C, and of course, Swift. This broader applicability opens up possibilities for cross-language projects and integration with other build systems. The system leverages the Swift Package Manager's package model for defining project structure and dependencies, providing a familiar and consistent experience for Swift developers.
One of the key innovations within Swift Build is the adoption of the Build System Interface (BSI), which serves as a well-defined communication layer between the build system and the underlying build tools. This abstraction allows for greater flexibility and choice in the tools used for the actual compilation and linking processes. Developers can, for instance, swap out different compilers or linkers based on their specific requirements, without needing to modify the core build system logic. The BSI further promotes innovation by enabling the creation of entirely new build tools that can integrate seamlessly with Swift Build.
The open-sourcing of Swift Build also facilitates community involvement. By making the source code publicly available, the Swift team invites contributions from developers worldwide, fostering a collaborative environment for enhancing the build system's capabilities and addressing any shortcomings. This collaborative approach is expected to accelerate the development and maturation of Swift Build, leading to a more robust and feature-rich build experience for all Swift developers. Furthermore, the move towards open source fosters transparency and trust within the community, allowing developers to scrutinize and understand the inner workings of the build system.
The blog post emphasizes that this transition is a gradual process. Initially, Swift Build will be focused on supporting Swift Package Manager projects on macOS, with future plans to extend support to other platforms and integrate with existing Xcode projects. The Swift team encourages community feedback and participation in shaping the future of Swift Build, emphasizing its importance in the continued growth and success of the Swift ecosystem.
Summary of Comments ( 50 )
https://news.ycombinator.com/item?id=42899703
HN commenters generally expressed cautious optimism about Apple open sourcing Swift Build. Some praised the potential for improved build times and cross-platform compatibility, particularly for non-Apple platforms. Several brought up concerns about how actively Apple will maintain the open-source project and whether it will truly benefit the wider community or primarily serve Apple's internal needs. Others questioned the long-term implications, wondering if this move signals Apple's eventual shift away from Xcode. A few commenters also discussed the technical details, comparing Swift Build to other build systems like Bazel and CMake, and speculating about potential integration challenges. Some highlighted the importance of community involvement for the project's success.
The Hacker News post "Apple is open sourcing Swift Build" generated a fair number of comments discussing the announcement of Swift Build's open-sourcing. Several commenters expressed cautious optimism, acknowledging that this move could potentially improve Swift's ecosystem, especially for server-side development and cross-platform compatibility. They also hoped for better integration with other build systems and improved build times.
Some commenters delved into more technical aspects, discussing the potential benefits of using Bazel, the build system underlying Swift Build. They pointed to its potential for remote caching and distributed builds, leading to faster build times, particularly for large projects. The potential for integrating with existing Bazel rules and extensions was also mentioned as a plus.
A few comments expressed skepticism, questioning whether this open-sourcing would truly be beneficial to the community. One commenter pointed out the challenge of making Bazel accessible to developers unfamiliar with its complexities. Another commenter questioned the level of community involvement Apple would allow and speculated on whether this move was primarily motivated by Apple's internal needs.
The potential impact on other build systems like CMake and Swift Package Manager (SPM) was also a topic of discussion. Some users wondered if this signaled the eventual deprecation of SPM. Others speculated that Swift Build might coexist with or even enhance these existing systems.
Several users highlighted the current limitations of Swift's build tooling, especially around dependency management and build times. They expressed hope that open-sourcing Swift Build would address these issues, leading to a smoother development experience.
A couple of comments also touched upon the licensing aspect of the open-sourcing, emphasizing the importance of a permissive license for wider community adoption and contribution. One user pointed out the Apache 2.0 license would enable its use in commercial products without requiring source code disclosure.
Finally, there were a few comments expressing general excitement about the announcement, seeing it as a positive step for the Swift community and a potential catalyst for further growth and innovation.