Missing package in 1.18

[ocket8888]

golang:1.17.8-alpine came with the git executable - presumably to accommodate go get - but golang:1.18-alpine does not - presumably because of the breaking change to go get that accompanied the new version.

[yosifkit]

git in the PATH? It is not installed in the alpine based image on purpose (and never has been).

Duplicate of #345/#347 (most recently), but see also #250 (comment); #119, #140, #153, #157, #166, #198, #209, #230, #239, #241, #251, #328.

[ocket8888]

I have an image that worked using golang:1.17.8-alpine and now fails to build an executable at runtime having changed only that base image with:

go: missing Git command. See https://golang.org/s/gogetcmd
        error obtaining VCS status: exec: "git": executable file not found in $PATH
 	Use -buildvcs=false to disable VCS stamping.

I assumed this was because git used to be in the $PATH, but it could just be a misleading error message

[ocket8888]

I went back to 1.17.8 and confirmed that there's no git anywhere on the image filesystem. So I'm not sure what was actually broken.

[ocket8888]

Found the exact command in the image's CMD that used to work but now doesn't:

go build --gcflags "all=-N -l" .

a go build that used to work no longer does

[dagood]

Here's a simple reproduction:

docker run -it --rm golang:1.18-alpine sh -c '
  mkdir /app; cd /app
  echo "package main;func main(){}" > main.go
  go mod init example
  mkdir .git
  echo ---
  go build .'

go: creating new go.mod: module example
go: to add module requirements and sums:
        go mod tidy
---
go: missing Git command. See https://golang.org/s/gogetcmd
error obtaining VCS status: exec: "git": executable file not found in $PATH
        Use -buildvcs=false to disable VCS stamping.

As it says, running go build -buildvcs=false . fixes it. Deleting .git also fixes it.

It looks like the new VCS status embedding feature in go 1.18 requires git, and instead of silently skipping buildvcs when git isn't available, it shows an error.

• cmd/go: "go test" seems to now require git due to -buildvcs golang/go#51723
• cmd/go: add (and default to) -buildvcs=auto golang/go#51748

[ocket8888]

But that's impossible, the Go team knows that it's unacceptable to ever make a breaking change under any circumstances 🙄

More seriously it looks from that bottom comment like they're open to fixing this - but at any rate it's not an issue with this Docker image, but an upstream problem. I'll take it up with them. Thanks.

[tianon]

If you really don't need .git for your builds at all, you can add .git to .dockerignore too 👀

[abursavich]

@ocket8888, please consider re-opening this issue.

There is a new std package in go 1.18, debug/buildinfo, which requires git in order to stamp the version control info on the binary (svn, hg, and bzr might be required too?). It's unfortunate that this may unnecessarily break some use cases (e.g. tests), but I think it's reasonable to expect that the official docker image should support the std packages of the language.

[ocket8888]

If you really don't need .git for your builds at all, you can add .git to .dockerignore too 👀

No, the source directory is mounted as a volume, not loaded into the build context, so that's unfortunately not an option.

It's unfortunate that this may unnecessarily break some use cases (e.g. tests), but I think it's reasonable to expect that the official docker image should support the std packages of the language.

I'll re-open if you want, but for the record I think Go ought to walk this back instead. And they yet might. No idea how long that would be, though, or if 1.18.0 would ever see it anyway.