fix: install toolchain version

[erikburt]

Changes

• Install the go version specified by the toolchain directive if it exists.

Motivation

This is the cause for the errors seen during go mod cache restores for all of our workflows.

Basically the actions/setup-go action doesn't install the provided toolchain version, so when executing a go command later, it fetches the toolchain version and adds the toolchain's modules to the go mod cache. When we go to restore the cache, it can't overwrite the modules which are already present.

Related: actions/setup-go#424

---

RE-3325

[github-actions]

I see you updated files related to core. Please run pnpm changeset in the root directory to add a changeset as well as in the text include at least one of the following tags:

• #added For any new functionality added.
• #breaking_change For any functionality that requires manual action for the node to boot.
• #bugfix For bug fixes.
• #changed For any change to the existing functionality.
• #db_update For any feature that introduces updates to database schema.
• #deprecation_notice For any upcoming deprecation functionality.
• #internal For changesets that need to be excluded from the final changelog.
• #nops For any feature that is NOP facing and needs to be in the official Release Notes for the release.
• #removed For any functionality/config that is removed.
• #updated For any functionality that is updated.
• #wip For any change that is not ready yet and external communication about it should be held off till it is feature complete.

🎖️ No JIRA issue number found in: PR title, commit message, or branch name. Please include the issue ID in one of these.

[jmank88]

IMHO we need to find a way to work with the tooling, not against it. This is an important feature for reproducability, and disallowing it can suddenly become a problem that surprises us later.

[jmank88]

Can we install the correct version if we read the toolchain first?

~/chainlink$ go mod edit -json | jq -r ".Toolchain"
go1.23.4

[erikburt]

AFAICT there's not a great solution to this. Is it possible that we keep the go version in sync with the desired toolchain version, then remove the toolchain directive?

What's the benefit of having a different go and toolchain versions? I don't know if there's subtleties, but it seems unnecessary.

[erikburt]

As you suggested, here is a workaround that gets the toolchain version, and installs that instead. actions/setup-go#457 (comment)

      - uses: actions/checkout@v4
      - id: toolchain
        run: echo "version=$(sed -ne '/^toolchain /s/^toolchain go//p' go.mod)" >> "$GITHUB_OUTPUT"
      - uses: actions/setup-go@v5
        with:
          go-version: ${{ steps.toolchain.outputs.version }}