The author expresses growing concern over the complexity and interconnectedness of Rust's dependency graph. They highlight how seemingly simple projects can pull in a vast number of crates, increasing the risk of encountering bugs, vulnerabilities, and build issues. This complexity also makes auditing dependencies challenging, hindering efforts to ensure code security and maintainability. The author argues that the "batteries included" approach, while beneficial for rapid prototyping, might be contributing to this problem, encouraging developers to rely on numerous crates rather than writing more code themselves. They suggest exploring alternative approaches to dependency management, questioning whether the current level of reliance on external crates is truly necessary for the long-term health of the Rust ecosystem.
Vincent Bernat's blog post, "Rust's dependencies are starting to worry me," expresses a growing concern about the increasing complexity and potential fragility introduced by the extensive use of dependencies in Rust projects. Bernat acknowledges the benefits of leveraging external crates, highlighting how they facilitate rapid development and code reuse, effectively preventing developers from constantly reinventing the wheel. However, he argues that the current dependency management system in Rust, primarily through Cargo, might be masking a looming problem of over-reliance on potentially unstable or poorly maintained external code.
Bernat’s central argument revolves around the concept of "dependency hell," a scenario where conflicting versions, abandoned projects, or breaking API changes in dependencies can lead to significant integration challenges and potentially paralyze development. He uses the analogy of building a house with prefabricated components; while convenient initially, relying heavily on external providers can create a vulnerable situation where the unavailability or alteration of a single component can compromise the entire structure.
The blog post specifically points to several factors contributing to this potential instability. The prevalence of small, hyper-specialized crates, while promoting modularity, also increases the overall number of dependencies a project relies upon, amplifying the risk of encountering problems. Furthermore, Bernat questions the long-term maintainability of these crates, expressing concern about the potential for maintainers to abandon projects, leaving downstream users with unsupported code. He illustrates this with a personal anecdote about a crucial dependency for his HTTP mocking crate becoming effectively unmaintained, forcing him to consider forking the project to ensure its continued functionality.
Bernat also discusses the challenge posed by semantic versioning and breaking changes. While semantic versioning aims to provide a clear indication of compatibility, he argues that its interpretation and enforcement are not always consistent, potentially leading to unexpected issues when upgrading dependencies. He specifically points to the difficulty of ensuring that transitive dependencies, those brought in indirectly through other crates, adhere to semantic versioning principles.
Furthermore, the post touches on the complexity of auditing dependencies for security vulnerabilities and the difficulty of assessing the overall quality and reliability of external code. While acknowledging the existence of tools like cargo-audit, Bernat implies that these tools alone are not sufficient to address the underlying issue of deep and intricate dependency trees. He briefly mentions the concept of vendoring dependencies as a potential mitigation strategy, but acknowledges its own set of complexities and drawbacks.
In conclusion, while appreciating the power and convenience of Rust's dependency management system, Bernat cautions against becoming overly reliant on external crates, advocating for a more mindful approach to dependency management, considering the long-term maintainability, security implications, and potential fragility that extensive dependency trees can introduce. He suggests the need for a broader community discussion and potential tooling improvements to address these growing concerns.
Summary of Comments ( 470 )
https://news.ycombinator.com/item?id=43935067
Hacker News users largely disagreed with the author's premise that Rust's dependency situation is alarming. Several commenters pointed out that the blog post misrepresents the dependency graph, including dev-dependencies and transitive dependencies unnecessarily. They argued that the actual number of dependencies linked at runtime is significantly smaller and manageable. Others highlighted the benefits of Rust's package manager, Cargo, and its features like semantic versioning and reproducible builds, which help mitigate dependency issues. Some suggested the author's perspective stems from a lack of familiarity with Rust's ecosystem, contrasting it with languages like Python and JavaScript where dependency management can be more problematic. A few commenters did express some concern over build times and the complexity of certain crates, but the overall sentiment was that Rust's dependency management is well-designed and not a cause for significant worry.
The Hacker News post titled "Rust’s dependencies are starting to worry me" (linking to an article expressing concern about the growth of Rust dependencies) generated a significant discussion with varied perspectives.
Several commenters echoed the original author's concerns, pointing to the increasing complexity of Rust projects and the potential for this complexity to introduce vulnerabilities or make maintenance more difficult. They highlighted the challenge of auditing numerous dependencies and ensuring their ongoing security. One commenter drew a parallel to the JavaScript ecosystem, expressing concern that Rust might be heading down a similar path of dependency bloat. Another pointed to the potential for "left-pad" style incidents where the removal of a small dependency can have cascading effects on the ecosystem. The idea of a "dependency explosion" leading to a future maintainability crisis was a recurring theme.
However, other commenters offered counterarguments and alternative viewpoints. Some argued that the number of dependencies is not inherently bad, especially when they are small and focused, promoting code reuse and modularity. They emphasized the benefits of Rust's strong type system and cargo's dependency management in mitigating some of the risks associated with numerous dependencies. One commenter pointed out that even with a large number of dependencies, the actual compiled binary size can remain relatively small. Others argued that comparing Rust's current state to JavaScript's mature ecosystem is premature and that Rust's dependency management is fundamentally different and more robust.
A few commenters focused on specific aspects of dependency management. One suggested using tools like
cargo-denyto enforce stricter dependency policies and audit for vulnerabilities. Another discussed the trade-offs between using direct dependencies versus relying on re-exports, suggesting that relying on re-exports can simplify dependency management and reduce the risk of version conflicts.Some commenters also discussed the cultural aspects of the Rust community, suggesting that the emphasis on correctness and thoroughness might help mitigate some of the risks associated with complex dependency trees.
Finally, several commenters mentioned alternative approaches to dependency management, like vendoring dependencies or using a monorepo structure, although acknowledging the trade-offs associated with these approaches.
Overall, the discussion reflected a nuanced understanding of the complexities of dependency management in Rust. While some expressed genuine concern about the growing number of dependencies, others argued that the benefits outweigh the risks, particularly given Rust's strong tooling and community focus on quality. The conversation highlighted the ongoing evolution of best practices in dependency management within the Rust ecosystem.