39 ms·

> they definitely never felt too long, compared to say Java. Woah... now I am the one who have to ask: what the hell are you on about?? I work on Rust and Jav

by brabel 5y ago

> they definitely never felt too long, compared to say Java. Woah... now I am the one who have to ask: what the hell are you on about?? I work on Rust and Java projects, if you exclude running tests, Java compiles very very fast compared to pretty much any language... Rust is a lot slower to compile even on the much smaller projects I've worked on... in this post, a very small project (I think it's like 16,000 LoC, it's mentioned in the beginning) was taking over a minute even on hot builds... To get a build to take this long in Java you would need to have several million LoC! Even if you don't use something like Gradle to cache compilation units and just compile everything from scratch with javac.

dmitriid 5y ago
> Java compiles very very fast compared to pretty much any language In my experience C# compiles faster, but I still agree with you on all points.
- yawaramin 5y ago
  Not surprising, considering the chief architect of C# is the guy famous for making Turbo Pascal.
- emn13 5y ago
  Build times have regressed considerably the past few releases (at least for me). Not that I'm complaining about the tradeoffs, the new features are generally worth it. Whats most annoying is that it's often hard to tell which features are expensive until you've already wasted a bunch of time introducing em. But I've got to say I'm super jealous of the level of introspection the rust compiler allows here. I'd definitely be willing to change a few C# coding patterns in code bases I maintain to benefit build times, but as is, that's a really painful trial and error process. And sometimes you get lucky finding the root cause, but if you don't... well, it's not a great experience.
Ygg2 5y ago
And I've worked on large Java projects. Things that have like 420+ dependencies (spring boot + some other requirements). I timed the maven clean compile. And it takes around 2min.
- brabel 5y ago
  Maven is very slow. Gradle and Bazel avoid doing wasteful things like Maven does so generally are a lot faster... if you want to know the speed of compiling Java you should just run `javac`, assuming Maven speed is Java compilation speed is far from correct even if a lot of projects still use Maven to build Java projects.
  - lenkite 5y ago
    Use Maven Daemon. (https://github.com/apache/maven-mvnd https://github.com/apache/maven-mvnd) . With Maven Daemon, traditional maven builds get a spectacular boost factor that put them ahead of Gradle. (Haven't tried Bazel though)
fasterthanlime 5y ago
Seems like you really need to finish reading the article: hot builds take 3s by the time I find the regression that caused pathological compile times.
- yawaramin 5y ago
  You mean, by the time you split up the project into a bunch of tiny crates and mention: > I don't love how the dependency graph looks After adding this complexity to the project, yes, some of the crates are building in ~3s, if they are the only ones that needed to be rebuilt. Meanwhile, in a Java project there is none of this artificial crate splitting. Sure, Java projects have other nonsense, but they don't force you to split up projects into tiny pieces to get decent compile times.
  - estebank 5y ago
    It's a tradeoff: if you make the file the language's compilation unit, then you can't have "circular imports" to allow end users divide their code in an ergonomic manner with fewer "arbitrary" restrictions. We can argue all year on whether Rust settled on the right side of that trade-off.
    - yawaramin 5y ago
      I'm just surprised that no one has (to my knowledge, anyway) tried this even experimentally. Wouldn't the potential build speed improvement be worth at least trying out the one-file-per-crate strategy?

by brabel 5y ago

dmitriid 5y ago

> Java compiles very very fast compared to pretty much any language In my experience C# compiles faster, but I still agree with you on all points.

yawaramin 5y ago
Not surprising, considering the chief architect of C# is the guy famous for making Turbo Pascal.
emn13 5y ago
Build times have regressed considerably the past few releases (at least for me). Not that I'm complaining about the tradeoffs, the new features are generally worth it. Whats most annoying is that it's often hard to tell which features are expensive until you've already wasted a bunch of time introducing em. But I've got to say I'm super jealous of the level of introspection the rust compiler allows here. I'd definitely be willing to change a few C# coding patterns in code bases I maintain to benefit build times, but as is, that's a really painful trial and error process. And sometimes you get lucky finding the root cause, but if you don't... well, it's not a great experience.

Ygg2 5y ago

And I've worked on large Java projects. Things that have like 420+ dependencies (spring boot + some other requirements). I timed the maven clean compile. And it takes around 2min.

brabel 5y ago
Maven is very slow. Gradle and Bazel avoid doing wasteful things like Maven does so generally are a lot faster... if you want to know the speed of compiling Java you should just run `javac`, assuming Maven speed is Java compilation speed is far from correct even if a lot of projects still use Maven to build Java projects.
- lenkite 5y ago
  Use Maven Daemon. (https://github.com/apache/maven-mvnd https://github.com/apache/maven-mvnd) . With Maven Daemon, traditional maven builds get a spectacular boost factor that put them ahead of Gradle. (Haven't tried Bazel though)

fasterthanlime 5y ago

Seems like you really need to finish reading the article: hot builds take 3s by the time I find the regression that caused pathological compile times.

yawaramin 5y ago
You mean, by the time you split up the project into a bunch of tiny crates and mention: > I don't love how the dependency graph looks After adding this complexity to the project, yes, some of the crates are building in ~3s, if they are the only ones that needed to be rebuilt. Meanwhile, in a Java project there is none of this artificial crate splitting. Sure, Java projects have other nonsense, but they don't force you to split up projects into tiny pieces to get decent compile times.
- estebank 5y ago
  It's a tradeoff: if you make the file the language's compilation unit, then you can't have "circular imports" to allow end users divide their code in an ergonomic manner with fewer "arbitrary" restrictions. We can argue all year on whether Rust settled on the right side of that trade-off.
  - yawaramin 5y ago
    I'm just surprised that no one has (to my knowledge, anyway) tried this even experimentally. Wouldn't the potential build speed improvement be worth at least trying out the one-file-per-crate strategy?