proposal: cmd/go: enhance `go version` to check if running latest revision of Go

[mzattahri]

The Go ecosystem lacks a standard way to check whether a system is running the latest revision of the current {major}.{minor} version of Go available.

https://go.dev/dl/?mode=json already provides a machine-readable (JSON) list of all the currently supported versions, but integrating it into a toolchain often requires complex scripts with external dependencies (e.g. curl, jq).

It seems like something the go command should handle in a consistent way.

My proposal is to extend go version with a new check command as following:

With no parameters, it would check whether the system is running the latest revision of the current major version installed.

> go version check
Running the latest revision of Go 1.20 (go1.20.3 darwin/arm64).
(code 0)

With a --latest flag, it would check whether the system is running the latest major release of Go.

> go version check --latest
Go 1.20 is available → https://tip.golang.org/doc/go1.20
(code 1)

Ideally, this would also serve warnings for out-of-support versions:

> go version check
Go 1.18 is no longer supported (go1.18.10 darwin/arm64).
(code 1)

[thediveo]

doesn't this break lots of existing scripts, etc.?

[mvdan]

Also see #57001.

[mzattahri]

@thediveo It would scripts calling go version against a binary named check, but there are workarounds for that (go check?). Not really opinionated about the syntax.

@mvdan Thanks, helpful context. I'd personally be opposed to making go version install anything on my system.

[ianlancetaylor]

CC @bcmills @matloob

[mzattahri]

FYI - Sharing some code I'm using today, and which could be adapted. https://gist.github.com/mohamedattahri/8cacc47b710eb3e2b170eef59bcd4a5b

[na4ma4]

I would think it would work better having something like:

$ go version --check tip
go1.24.0
(Exit Code: 1)

$ go version --check '>=1.20'
go1.24.0
(Exit Code: 0)

$ go version --check '<=1.21'
go1.24.0
(Exit Code: 1)