Force `go` to always use the local toolchain (i.e. the one the one that
shipped with the go command being run) via setting the `GOTOOLCHAIN`
environment variable to `local`[1]:
> When GOTOOLCHAIN is set to local, the go command always runs the
bundled Go toolchain.
This is how things are setup in the official Docker images (e.g.[2], see
also the discussion around that change[3]). The motivation behind this
is to:
* Reduce duplicate work, the action will install a version of Go, a
toolchain will be detected, the toolchain will be detected and then
another version of Go installed
* Avoid Unexpected behaviour: if you specify this action runs with some Go
version (e.g. `1.21.0`) but your go.mod contains a `toolchain` or `go`
directive for a newer version (e.g. `1.22.0`) then, without any other
configuration/environment setup, any go commands will be run using go
`1.22.0`
* TODO: link image
This will be a **breaking change** for some workflows. Given a `go.mod`
like:
module proj
go 1.22.0
Then running any `go` command, e.g. `go mod tidy`, in an environment
where only go versions before `1.22.0` were installed would previously
trigger a toolchain download of Go `1.22.0` and that version being used
to execute the command. With this change the above would error out with
something like:
> go: go.mod requires go >= 1.22.0 (running go 1.21.7;
GOTOOLCHAIN=local)
[1] https://go.dev/doc/toolchain#select
[2] dae3405a32/Dockerfile-linux.template (L163)
[3] https://github.com/docker-library/golang/issues/472
f54e8eea6b