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Comment by troad | Hacker News Reader

Dependency bloat is an issue with Rust in general. The dependency trees for any meaty Rust project quickly become pretty horrifying. Auditing all these dependencies is infeasible, and my level of confidence in a lot of them is fairly low.

I worked with Rust for a few years, and with the benefit of a few years' experience, I don't think I'll be touching Rust again until the ecosystem matures a great deal (which will only come with significant corporate adoption), or if I need something for a no-std, no-deps, strictly-a-C-replacement kind of project. (Though Zig might edge out Rust for this use case once it stabilises.)

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> The dependency trees for any meaty Rust project quickly become pretty horrifying.

s/Rust//

This is really no different from any other language.

At least Rust, with Cargo, makes it easy to scan your dependencies. And many notable Rust projects attempt to keep third party dependencies to a minimum.

C++ gives you absolutely nothing to work with. Other languages with package managers don't keep dependency trees shallow. You're holding Rust up to a standard that nothing meets.

> And many notable Rust projects attempt to keep third party dependencies to a minimum.

I don't think this is true. The only two major Rust crates that manage to keep their dependencies light are tokio and serde, and these are highly atypical projects. For a more typical example, look at something like axum (running `cargo tree` for project with a single dependency on axum returns 121 lines).

> This is really no different from any other language.

> You're holding Rust up to a standard that nothing meets.

Respectfully, I think you're creating a bit of a false dichotomy here. I'm not demanding perfection, I'm merely noting that I've found Rust dependency trees to grow noticeably faster than dependency trees in equivalent languages. You add two dependencies in Rust, and suddenly you have a dozen dependencies of dependencies of dependencies, including at least three different logging crates. In the world of C, which is what Rust is trying to displace, that's just not going to pass muster.

Rust is a very fine language with a bit of a dependency addiction (a dependency dependency?). I honestly don't see what service it does to the language to pretend otherwise.

> You add two dependencies in Rust, and suddenly you have a dozen dependencies of dependencies of dependencies, including at least three different logging crates. In the world of C, which is what Rust is trying to displace, that's just not going to pass muster.

In the world of C, how many libraries just vendor their dependencies, so they're just not easily visible in a dependency tree?

I think the GP's point was that all modern languages (and some of the older ones) have this problem - in fact, JS is infamous for it. Therefore, I don't think it's really a pro or a con on its own - only in the context of your business and problem.

tokio and serde are certainly not the only ones. You can put almost all of my crates into that category too.

The problem with your framing is that you look at this as a "dependency addiction." But that doesn't fully explain everything. The `regex` crate is a good case study. If it were a C library, it would almost certainly have zero dependencies. But it isn't a C library. It exists in a context where I can encapsulate separately versioned libraries as dependencies with almost no impact on users of `regex`. Namely, it has two required dependencies: regex-syntax and regex-automata. It also has two optional dependencies: memchr and aho-corasick.

This isn't a case of the regex crate farming out its core functionality to other projects. Indeed, it started as a single crate. And I split its code out into separately versioned crates that others can now use. And this has been a major ecosystem win:

* memchr is used in all sorts of projects, and it promises to give you exactly the same implementation of substring search that the regex crate (and also ripgrep) use in your own projects. Indeed, that crate is used here! What would you do instead? If you were in C-land, you'd re-roll all of the specialized SIMD that's in memchr? For x86-64, aarch64 and wasm32 right? If you haven't done that sort of thing before, good luck. That'll be a long ramp-up time.

* aho-corasick is packaged as a stand-alone Python library that is quite a bit faster than pyahocorasick: https://pypi.org/project/ahocorasick-rs/ There's tons of other projects on crates.io relying on aho-corasick specifically, separately from how its used inside of `regex`.

* regex-syntax gives you a production grade regex parser. More than that, it gives you exactly the same parser used by the regex crate. People have used this for all sorts of things, including building their own regex engine without needing to re-create the parser (which is a significant simplification).

* regex-automata gives you access to all of the internal APIs of the regex engine. This is all the stuff that is too complex to put into a general purpose regex library targeting the 99% use case. As far as I know, literally no other general purpose regex engine has ever attempted this because most regex engines are written in C or C++ where you'd be laughed out of the room for suggesting it because dependency management is such a clusterfuck. Yet, this has been a big benefit to other folks. The Yara project uses it for example, and the Helix editor uses it to search discontiguous strings: https://github.com/helix-editor/helix/pull/9422 (Instead of rolling your own regex engine, which is what I believe vim does.)

This isn't dependency addiction. This is making use of separately versioned libraries to allow other projects to depend on battle tested components independent of their primary use case. Yet, if people repeat this kind of process---exposing internals like I did with the regex crate---then you wind up with a bigger dependency tree.

Good dependency management is a trade-off. One the one hand, it enables the above to happen, which I think is an objectively Good Thing. But it also enables folks to depend on huge piles of code so easily that it actively discourages someone from writing their own base64 implementation. But as should be obvious, it doesn't prevent them from doing so: https://github.com/BurntSushi/ripgrep/blob/ea99421ec896fcc9a...

Good dependency management is Pandora's box. It has been opened and it is never going to get closed again. Just looking on and calling it an addiction isn't going to take us anywhere. Instead, let's look at it as a trade-off.

Super interesting take, thanks for sharing your thoughts.

I like your trade-off framing, but I do think that your argument fails to take account of something important here, which I'll try to illustrate with an example.

Let's say I want to run a simple modern web stack. In C#, I might pull in ASP.NET and EF Core. In Java, I might pull in Spring. In Rust, I might pull in axum, axum-server, rustls and sqlx. From those four deps alone, and before I have written a single line of code, I now have a three hundred and fifty-two line long `cargo tree`. There are three things to note on this.

First, and most obviously, this is far too many dependencies of dependencies, and this is before I add in a lot of other crates I'll need to work with this stack, or for my business logic. I can't seriously rely on - or even keep up with - a dep tree like this for a single and relatively simple project.

Second, a lot of these dependencies are made by anonymous users on github, are documented solely on Discord, change frequently, and do not appear to warrant a high degree of confidence. If Rust continues to gain traction, we will absolutely see security issues à la Pollyfill.JS or xz. For my livelihood, I'm necessarily going to place more trust in Microsoft's ASP.NET or VMWare's Spring than in @animewaifu420's three dozen half-abandoned packages and their 'dank' Discord.

Third, despite pulling in twenty-five times more dependencies than Alpine requires to run an OS, this is actually an extremely barebones web stack. No code-first database migrations, no authentication or authorisation, no internationalisation, no named routes, just to take some random basic features - all of this requires further crates (and, in turn, many dozens of further dependencies of dependencies.)

I'm using web as an illustrative example here, but this is an issue that permeates the ecosystem. I've faced similar issues for other use cases as well.

I like your trade-off framing, but I respectfully think it comes out strongly against Rust from an end user's perspective, at least at this point in Rust's history. I also think it elides over something important - the fact that Rust need not actually be like this. There's no reason Rust couldn't, in the future, have fully-featured crates, with dramatically curtailed dep trees and wide industry buy-in. But it's just not there at this stage. And so I return to my initial post - I quite like Rust, I've previously used it for years, but the ecosystem is years away from a sufficient level of maturity for me to feel inclined to return to it for any significant work at this stage.

> I can't seriously rely on - or even keep up with - a dep tree like this for a single and relatively simple project.

Our dependency trees in `uv` and `ruff` at Astral are bigger than this. We rely on it and keep up with it. We do not spend most of our time dealing with the dependency tree. (Although I do think our compile times are longer than would be nice.)

> For my livelihood, I'm necessarily going to place more trust in Microsoft's ASP.NET or VMWare's Spring than in @animewaifu420's three dozen half-abandoned packages and their 'dank' Discord.

If this ends up being true, then that means there is financial incentive to provide something more holistic, right?

I don't know what "dank" Discords have to do with anything here.

From my perspective, I see a lot of derision and vague feelings in your commentary, but little hard data. Tons of production web applications are built in NodeJS on orders-of-magnitude larger dependency trees. Tons of peoples' livelihoods depend on it.

To be honest, I have a lot of the same feelings as you. I don't like large dependency trees either. But that tends to be more connected to tangible problems like compile times.

> There's no reason Rust couldn't, in the future, have fully-featured crates, with dramatically curtailed dep trees and wide industry buy-in.

There's no reason C couldn't have better dependency management either, right? But it doesn't. And the problem isn't just technical.

> but the ecosystem is years away from a sufficient level of maturity for me to feel inclined to return to it for any significant work at this stage.

I suspect the ecosystem is more mature than you think it is, particularly if your understanding of maturity boils down to just a single number of dependencies. But like, if you had written this comment originally, I probably wouldn't have replied. I don't think what you're saying is totally unreasonable, but I also don't see this changing either. Like, if Microsoft wanted to come in and build a nice web framework for Rust, I think it's very likely it would be built on top of the existing crate ecosystem. I don't think they would, for example, roll their own HTTP implementation unless there was some technical reason that `hyper` wouldn't work for them. I do not think they would do it just to get the dependency count down.

What you're seeing is a manifestation of a million tiny little decisions. Should I write my own URL parser? Or should I use a crate for it that I know is also used in production by a number of large companies? Why would you choose to roll your own? (Again, excepting technical reasons.) You wouldn't. You would use the one that already exists. And this decision procedure repeats over-and-over. Big companies aren't immune to it either.

In any case, I did say "trade off" and not "Rust's way is always better." So my reply makes room for viewpoints like yours, where as I think your original comment didn't make room for a more balanced take. That's why I responded.

Responding to the Discord point, charitably, I think the person you're replying to is saying that Discord is a poor documentation platform that has some fatal flaws, and I do think it has unfortunately replaced web forums in a lot of contexts, which means a couple things:

1. It's unsearchable and opaque: you can't really do anything but the most basic of searches on Discord and getting support or finding previous/similar questions can be incredibly difficult. This also has the strong disadvantage of being unarchivable with makes the next issue more important.

2. It's controlled by a single entity and the viability of Discord, from both a service provider perspective and a community perspective is uncertain. For all we know, Discord, the company, could die without any warning, or there could be policy decisions which make hosting communities untenable. If that happens, it'd be incredibly difficult to get stuff off of there. With more decentralized communities, or even centralized, but internet-visible ones, there are potentially archives and backups that can help restore information.

This, imo, makes it not a great choice for a software project's forum or whatever. Maybe general IRC-style chat where conversations tend to be relatively ephemeral anyway? Sure. But it's not a great forum or wiki replacement imo.

I'm not sure languages without a package manager being the default are nearly as bad.

When it is trivial (like running a single command line or a single line in a file like cargo.toml), having a proliferation of dependencies is so easy it almost becomes guaranteed. But in languages like c++ where not everyone uses them (even if several PMs exist) adding a dependency to a library is a much bigger deal as you either have to use something like git submodules or manage them yourself OR make any user of your library go get the correct versions themselves.

> I'm not sure languages without a package manager being the default are nearly as bad.

The autoconf or cmake list of included libraries for many non-trivial C++ projects is usually just as long as stuff in Cargo, especially when breaking up Boost, Qt, or other megaframeworks into individual libraries.

They do "make any user of your library go get the correct versions themselves" but that has been far less of a problem this century thanks to OS package management.

The thing is, when adding dependencies _isn't_ trivial, you end up vendoring. You aren't gonna thoroughly test your command line parser if it is a very small feature of your overall project. A dedicated command line parser lib will (more likely than you in this case) thoroughly test their implementation.

I think it's important to figure out what you're comparing though.

A language that makes it easy to pull in dependencies also encourages breaking code into separate modules.

Languages that make dependency management hard tend to have larger, heavier dependencies. Two dependencies in such a language are more likely to have duplicate functionality between them, instead of sharing the functionality through another dependency.

Is it better to vet many smaller dependencies, or fewer large ones that likely duplicate a lot of stuff? It depends on what those dependencies are.

I don't think just looking at dependency counts is that useful. Many libraries that would be a single dependency in other languages are split into several because they are useful on their own.

> I'm not sure languages without a package manager being the default are nearly as bad.

Javascript doesn't have a specified package manager.

It’s different from Go, but then, Go is probably not the language you’re going to replace Rust with.

(I know it’s exactly different from Go’s dependency management, but you frankly rarely need any thing outside of the STL in Go.)

And yet with Python and JS I don’t need to pull a freaking third-party library for something as basic as JSON.

Most of my Rust projects don't need a JSON parser. You probably haven't been a programmer that long if you think JSON is "basic". If it was 20 years ago, you'd be arguing for an XML parser in Rust's stdlib. In 20 years I'm sure it will be something else. File/data formats come and go. The stdlib of a systems programming language shouldn't be taking on a forever maintenance burden for something that likely won't be in widespread use for all that long.

Nope, instead it's pulled into every project whether you need it or not.

Pulled how?

If I don't need it, it's not basic it's just useless.

> This is really no different from any other language.

There are languages with big standard libraries and first party frameworks.

I can build a complex web app in C# using only packages published by Microsoft in ASP.NET and EF.

Python ships with a lot of "batteries included".

Not saying I expect that from rust considering the funding/team size discrepancy and language targets - but I disagree that every language is same in this regard - JS/Node is notoriously bad, Rust is around C++ level, and plenty of higher level languages have first pary/standard library stacks.

Moment you add something to std it's effectively died. Strong backwards guarantees will choke development of library.

Python std is where libraries go to die.

Who says that's a bad thing ? Sometimes things are good enough and just need to be vetted and maintained.

Rarely that's ever true. Hardware and software assumption will change over time. E.g. Simd is rare and not available to 99% of hardware has it, pointer is 16/32/64 bit wide, that API is available, SGML/JSON/XML is all parsing you will ever need.

Let's be real about dependencies https://wiki.alopex.li/LetsBeRealAboutDependencies

> A medium-sized Rust project can easily tip the scales at 2-300 crates, which is still rather more dependencies than anything I’ve looked at here, but that’s explained by the simple fact that using libraries in C is such a monumental pain in the ass that it’s not worth trying for anything unless it’s bigger than… well, a base64 parser or a hash function.

It's odd that this article spends so much time arguing that Rust is no different than C or C++, only to concede at the end that Rust projects do have more dependencies.

Because Rust has Cargo which makes it trivial to include dependencies.

C developers constantly reinvent because C dependency management is such a joke that no one bothers.

This is so on-point. Number of dependencies is correlated with ease of package management.

If you have a well-working package manager you're more likely to use a dependency than just rewrite that little part of your code.

For little programs written in C or C++ this usually means that people write their own buggy CLI parsing that doesn't produce a proper help message and segfaults with the wrong combination of arguments. In Rust people use clap. And they just need to derive on their CLI arguments struct.

And this process happens for every "small" dependency. In the end you're faster developing with cargo, you get a more professional result, probably you can even generate an executable for ARM and Intel without changing anything.

But OMG, you have a dependency tree.

> Number of dependencies is correlated with ease of package management.

I disagree with this, Python makes it trivial to add dependencies. [1] And yet Python developers tend to have the mentality of an older generation of software developers, pre-node/npm, and believe in keeping most things light. That starts with the language maintainers having a vision that says this should be possible, by including the batteries most people need for mid-size projects.

This has a compounding effect. People writing the dependencies that your dependencies will use might not even need dependencies outside of the Python standard library. In Rust, those dependencies have dependencies which have dependencies. You get a large tree even when everyone involved is being relatively sane. When one or two projects are not careful, and then everyone uses those projects ...

When I'm writing Rust, I eternally have the infuriating dilemma of picking which dependency to use for a relatively common operation. Having one blessed way to do something is an enormous productivity advantage, because it's never on you to vet the code. The disadvantages of a large stdlib are pretty overstated; even when an outside library outperforms the internal one (like Python's "requests"), the tendency will be for everyone to form a consensus about which outside library to use (like Python's "requests"), because that's how the ecosystem works.

Using technology designed 25 years ago has big advantages for Linux developers as well. Even when I need to add a dependency in Python, chances are I don't have to install one in my development environment because I can experiment with the shared dependencies already installed on my operating system. And I can look to the maintainers of the software I use - and my system maintainers - for implicit advice about which libraries are reliable and trustworthy, and use those. Rust, Go, etc., throw all of this out in the name of convenience for developers, but it's precisely as a developer that I find this mentality frustrating.

[1] People complain about the UX of e.g. pip in certain situations, but (regardless of whether it's a reasonable complaint) it's not the same issue as maintaining a stack of dependencies in the language itself being difficult.

> I disagree with this, Python makes it trivial to add dependencies.

In python it's surely easier to add dependencies than C/C++, but it's harder than in Rust and not so trivial. Everyone using your script has to manually run pip to _globally_ install dependencies, unless you use virtual environments which can take a requirements.txt file, which just show how the builtin dependency management is not enough.

> When I'm writing Rust, I eternally have the infuriating dilemma of picking which dependency to use for a relatively common operation.

Likewise in python you might wonder which library to use between urllib, urllib2, urllib3 and reqwest. People not familiar with python might even fail to guess which ones are part of the stdlib.

Granted that's just one specific example, but it shows pretty nicely how there will always be a library with a better design and a stdlib module that's good enough right now will likely not hold the test of time, ultimately resulting in bloat.

C has no dependency management. There are various other package management you can use with C though. I am quite happy with my Linux distribution package manager.

But I have to say it clearly: cargo is a supply chain disaster and ever changing dependencies are major problem for Rust. Rust programs having many dependencies if not a good thing.

I wonder if Go tooling does the job umm... "better" here. At least faster build time and debug build is much smaller.

At my current company, we handle payment, transaction etc with Go (some Fiber, some Echo). None of the projects reach 100 MB, and my pkg folder size is around 2.5 GB-ish. Those are the dependencies of all of my Go codebase. Well not bad.

Compare it with building a Rust sqlite web API which easily eat 3 GB disk. 10 similar projects may eat at least 30 GB.... :D

Disclaimer: I don't use Rust for work... yet. Only for personal tinkering.

To me the size of the codebase after installing dependencies isn’t that relevant. Are you starved for 30GB for your work? My current company has projects in PHP, rust, and a bunch of frontend projects with all the modern build tooling.

The largest service we deploy is ~300Mb, maybe 200Mb if you exclude copy of Monaco that we ship in the Dist folder. That web server will have terabytes of database storage behind it and 32 or 64 Gb of Redis/Memcached behind it. If we add in the Elasticsearch we’ve got another terabyte and a ton of memory.

If those dependencies aren’t checked into version control or being shipped to prod does it really matter?

For an application developer like me? No. It's technically not a dealbreaker. But probably more like a question for compiler devs.

Odd indeed.

It's also worth noting that the article has a real apples != oranges problem. Things like 'libsystemd' are not in any way comparable to your typical Rust crate.

> Though Zig might edge out Rust for this use case once it stabilises.

Zig has a meaningful advantage in the context of this discussion: lazy compilation. The compiler won't even semantically analyze a block of code unless the target requires that to happen.

Currently, dependencies are more eager than they really need to be, but making them just as lazy as compilation is on the roadmap. Lazy compilation means no tree shaking is needed, and it means that the actual build-graph of a program can be traced on a fine-grained level. We might not be able to audit a hundred dependencies, but auditing the actual used code from all those dependencies might be more practical.

This is well positioned to handle a common pattern: `small-lib` provides some useful stuff, but also has extensions for working with `huge-framework`, and it needs to have `huge-framework` as a dependency to do so. Currently this means that the build system will fetch `huge-framework`, but if we can get it lazy enough, even that won't have to happen unless the code consuming `small-lib` touches the `huge-framework` dependency, which won't happen unless the program itself needs `huge-framework`.

Existing build systems don't do such a great job with that kind of structure, and the culprit is eagerness.

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