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Taking Go modules for a spin

dave.cheney.net

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Re: Taking Go modules for a spin

#11

Post by bsaul »

jakoblorz wrote: post #8
bsaul wrote: post #6

I haven’t followed the history of the feature, but could anyone explain why we had to wait until version 11 to be able to build a project from any location we wanted ? I’m having a hard time believing it’s purely for technical reasons, but then i don’t understand either what has changed that makes it a desirable feature now rather than before.

Go has always been extensively opinionated (gofmt is just one example of that). This is also the beauty of Go - everything is just as expected once you understand the "opinions". The rather late support of "out-of-tree" building might be caused by a conflict between groups pressing to refrain from the $GOPATH approach (rising in size due to rising Go popularity itself) and Go Dev Team / early-adopters especially as t…

I'm having a hard time believing the go core team changed its mind upon popular pressure only. Are you sure there wasn't a real-life painful scenario that appeared or grew in importance , and convinced them an alternative system had to be provided ?

Re: Taking Go modules for a spin

#12

Post by benesch »

bsaul wrote: post #6

I haven’t followed the history of the feature, but could anyone explain why we had to wait until version 11 to be able to build a project from any location we wanted ? I’m having a hard time believing it’s purely for technical reasons, but then i don’t understand either what has changed that makes it a desirable feature now rather than before.

I can't speak to this with absolute certainty, but I have some speculation to offer. The story of GOPATH is tightly intertwined with the story of package management.

Go is a Google project, and Google has a very unique approach to package management: commit everything to the monorepo. The GOPATH is, in essence, a monorepo. If you want to change the API of a library, well, you can just change all its callers across your GOPATH, too. And so for a long time the Go team was unconvinced that package management was a problem.

For example, the Go FAQ [0] still has this to say:

> How should I manage package versions using "go get"?

> "Go get" does not have any explicit concept of package versions. Versioning is a source of significant complexity, especially in large code bases, and we are unaware of any approach that works well at scale in a large enough variety of situations to be appropriate to force on all Go users...

> Packages intended for public use should try to maintain backwards compatibility as they evolve. The Go 1 compatibility guidelines are a good reference here: don't remove exported names, encourage tagged composite literals, and so on. If different functionality is required, add a new name instead of changing an old one. If a complete break is required, create a new package with a new import path.

It is true that if you write perfectly backwards compatible code, then you don't have a versioning problem, but if you think that's a viable solution you're ignoring certain realities of software engineering.

It wasn't until early last year that Russ Cox [1] publicly declared that versioning was a problem and set out to introduce a package manager into the Go toolchain. As it turns out, GOPATH is entirely incompatible with the approach to package versioning that the Go team settled on. You simply can't have two versions of the same package in your GOPATH, unless you're willing to rename one and rewrite all the import paths. Given that public opinion had turned again GOPATH [2], it was finally time to do away with it.

So it took about a year and a half from the time the Go team admitted GOPATH was a problem to shipping a release that made it unnecessary. That's really not too bad. The frustrating part of this saga were the first seven years during which the Go team refused to admit there was a problem at all.

[0]: https://golang.org/doc/faq#get_version [1]: https://research.swtch.com/go2017 [2]: https://github.com/golang/go/issues/17271

Re: Taking Go modules for a spin

#13

Post by coldtea »

jakoblorz wrote: post #8
bsaul wrote: post #6

I haven’t followed the history of the feature, but could anyone explain why we had to wait until version 11 to be able to build a project from any location we wanted ? I’m having a hard time believing it’s purely for technical reasons, but then i don’t understand either what has changed that makes it a desirable feature now rather than before.

Go has always been extensively opinionated (gofmt is just one example of that). This is also the beauty of Go - everything is just as expected once you understand the "opinions". The rather late support of "out-of-tree" building might be caused by a conflict between groups pressing to refrain from the $GOPATH approach (rising in size due to rising Go popularity itself) and Go Dev Team / early-adopters especially as t…

>While I can see the intention of Go modules, I believe that many people which belong to the first group migrated from other languages like JavaScript and expect to migrate the workflow as well. I highly encourage everyone to try the $GOPATH approach before rooting for any side.

I've tried it. Can we now get real modules?

Re: Taking Go modules for a spin

#14

Post by mattlondon »

benesch wrote: post #12
bsaul wrote: post #6

I haven’t followed the history of the feature, but could anyone explain why we had to wait until version 11 to be able to build a project from any location we wanted ? I’m having a hard time believing it’s purely for technical reasons, but then i don’t understand either what has changed that makes it a desirable feature now rather than before.

I can't speak to this with absolute certainty, but I have some speculation to offer. The story of GOPATH is tightly intertwined with the story of package management. Go is a Google project, and Google has a very unique approach to package management: commit everything to the monorepo. The GOPATH is, in essence, a monorepo. If you want to change the API of a library, well, you can just change all its callers across yo…

+1 - I believe that it stems from the monorepo mindset.

That's fine and works perfectly well in the appropriate environment (e.g. large structured work environment with processes etc etc), but for my personal work I prefer to just checkout wherever the hell I want and go from there. Really looking forward to module support so I can use golang for some personal small-scale projects easily without having to go through a lot of the ceremony of setting go up on say a raspberry pi - just checkout and go (no pun intended) will be a breath of fresh air.

Re: Taking Go modules for a spin

#15

Post by hellcow »

I've been using go modules in my company for several months now. Everything has "just worked." It's at least 1 order of magnitude faster than dep.

It's worth noting that go modules use a novel dependency resolution algorithm which is extremely simple to reason about/implement, fast, and produces more reliable builds than npm/bundler/cargo. That's why I was excited about it, anyway. It removes the ever-present NP-complete assumptions in this space, so from a computer science perspective it's extremely interesting.

Re: Taking Go modules for a spin

#16

Post by azhenley »

I recently started to learn Go and everything has gone smoothly... except the bizarre, unfriendly GOPATH and forced project structure.

It was not fun when VS Code (with the Go plugin) would automatically remove my imports every time I saved the file because it couldn’t find it.

Re: Taking Go modules for a spin

#17

Post by atombender »

benesch wrote: post #12
bsaul wrote: post #6

I haven’t followed the history of the feature, but could anyone explain why we had to wait until version 11 to be able to build a project from any location we wanted ? I’m having a hard time believing it’s purely for technical reasons, but then i don’t understand either what has changed that makes it a desirable feature now rather than before.

I can't speak to this with absolute certainty, but I have some speculation to offer. The story of GOPATH is tightly intertwined with the story of package management. Go is a Google project, and Google has a very unique approach to package management: commit everything to the monorepo. The GOPATH is, in essence, a monorepo. If you want to change the API of a library, well, you can just change all its callers across yo…

The Go team, for years, actually insisted that package management was something the Go community had to go and figure out. As you say, Google uses a monorepo where they check everything into a single tree. One of the core Go developers -- I forget who, unfortunately -- actually claimed at one point that they didn't want to design a package management system because they didn't know how; since Google used a monorepo, designing a real package management system not based on a monorepo would apparently be beyond them.

My personal theory is that what made Russ Cox cave in was his discussions with Sam Boyer. Cox thought Boyer was going down the wrong path, and thought he had a better solution. Unfortunately, the Go community didn't seem to have read the discussions the two were having, because pretty much everyone thought Dep (Boyer's tool) was blessed by the Go team and was going to be the official package management tool. I can forgive the drama of the end result is a real, non-Google package management system, though.

(While I didn't appreciate the drama, I'm somewhat relieved Dep is not going to be the official solution. Dep is okay when it works, but inherits pretty much all the warts of Glide, which Boyer also worked on. Glide has been an absolute nightmare to work with. Dep is in fact worse than Glide in some respects -- due to weaknesses in its solver, it's completely incompatible with certain significant community packages such as the Kubernetes client. Of course, Dep is not yet 1.0, but I would not say things were looking that promising.)

Re: Taking Go modules for a spin

#18

Post by weberc2 »

hellcow wrote: post #15

I've been using go modules in my company for several months now. Everything has "just worked." It's at least 1 order of magnitude faster than dep. It's worth noting that go modules use a novel dependency resolution algorithm which is extremely simple to reason about/implement, fast, and produces more reliable builds than npm/bundler/cargo. That's why I was excited about it, anyway. It removes the ever-present NP-comp…

Can you elaborate on why it’s easier to reason about than Cargo et al? I’ve heard a lot of theoretical criticism of Go modules for not taking Cargo’s approach so I’m surprised to hear an experience report to the contrary.

Re: Taking Go modules for a spin

#19

Post by weberc2 »

azhenley wrote: post #16

I recently started to learn Go and everything has gone smoothly... except the bizarre, unfriendly GOPATH and forced project structure. It was not fun when VS Code (with the Go plugin) would automatically remove my imports every time I saved the file because it couldn’t find it.

I like the consistent, sane project structure, but GOPATH is an odd duck to be sure.

Re: Taking Go modules for a spin

#20

Post by neuland »

azhenley wrote: post #16

I recently started to learn Go and everything has gone smoothly... except the bizarre, unfriendly GOPATH and forced project structure. It was not fun when VS Code (with the Go plugin) would automatically remove my imports every time I saved the file because it couldn’t find it.

Removing imports sounds like a gofmt issue. That is the linter / formatter for all Go code. If you don't run the linter and try to build the code, it won't work anyway. For example, I added the net/http package to a file without using it and got this error when running `go build` without doing `go fmt` first:

    ./example.go:8:9: imported and not used: "net/http"
So VS Code's Go plugin removes the unused import because otherwise the code is invalid. I'm a vim user and `vim-go` has the same behavior.
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