cmd/go: "get -tool" should fail if "go" is below 1.24 in go.mod

[dolmen]

When a tool is registered in go.mod with go get -tool, ensure that the go requirement is at least 1.24.0. If that isn't the case, suggest to the user to upgrade (go mod edit -go=1.24.0).

Rationale

go1.23 can't parse go.mod with a tool directive.

Go version

go version go1.24.5 darwin/arm64

Output of go env in your module/workspace:

GO111MODULE=''

What did you do?

$ cat go.mod
module github.com/dolmen-go/goeval

go 1.23.0

require (
	golang.org/x/mod v0.24.0
	golang.org/x/tools v0.31.0
)

require golang.org/x/sync v0.12.0 // indirect

tool github.com/dolmen-go/goeval

What did you see happen?

go1.23.11 fails to parse a go.mod that contains a tool directive:

$ go1.23.11 build
go: errors parsing go.mod:
go.mod:12: unknown directive: tool

https://github.com/dolmen-go/goeval/actions/runs/16493582443/job/46633886516#step:4:7

What did you expect to see?

Either:

• go 1.23 to ignore the tool directive
• or go 1.24+ go get -tool fails to add the tool and suggests to increase the minimum go version in go.mod (go mod edit -go=1.24.0)

[gabyhelp]

Related Issues

• cmd/go: improve error message for unparsable, too-new, go.mod #70979 (closed)
• cmd/go: go toolchain version switch doesn't work when only language version is set in go.mod #65580 (closed)
• cmd/go: `go env GOMOD` tries to download newer toolchain #61455 (closed)
• cmd/go: some documentation issues for new 1.24 'go tool' features #71663
• cmd/go: using go get go@{version} in a module without a go directive can print a misleading "downgraded" message #63507
• cmd/go: go directive is insufficiently documented for module authors to be able to make a decision about its value #30791 (closed)
• cmd/go: on malformed "go mod edit -go", suggest current version of go, not hardcoded 1.12 #32286 (closed)
• Should the `go` directive in `go.mod` a semver version (including patch), or not? #68971 (closed)

Related Documentation

• Go Modules Reference > go.mod files > go directive
• go.mod file reference > go > Notes

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