Update Go

Raise the Go versions pinned across a branch's Dockerfiles and workflows, on one or more branches at a time, then hand the user a script that commits, pushes, and opens the pull requests.

Dependabot cannot do this. Its docker ecosystem sees only Dockerfile and Dockerfile.dev; it cannot see the container.image pins in the workflows, and it cannot tell the two roles below apart. That is why Go is excluded from .github/dependabot.yml and why this skill exists.

The two roles

Every Go version pin in this repository serves exactly one of two roles. The comments at each site say which. Read the comment before editing the line.

Never raise the test minor. Patch bumps inside a minor are always safe. A minor raise forces a golangci-lint upgrade, which surfaces new findings needing code or config changes -- a separate, human-driven change. Root go.mod's go directive is the authority on which minor the branch tests against; if the test sites disagree with it, stop and report rather than guessing.

Site inventory

The layout differs by branch, so discover, do not assume. Sites seen so far:

ship

• Dockerfile -- every FROM ... golang:<ver>-<variant> stage (back-end-builder, helm-builder)
• .github/workflows/release.yaml -- image: &golangImage golang:<ver>-... and the actions/setup-go step's go-version:
• .github/workflows/ci.yaml -- the build-cli job's container.image
• .github/actions/setup-go/action.yaml -- the go-version input default: (this action's default is the ship version; jobs that test override it)

test

• Dockerfile.dev -- the FROM golang:<ver>-<variant> base image
• .github/workflows/ci.yaml -- go-version: &goTestVersion "<ver>" or image: &golangTestImage golang:<ver>-<variant>, depending on branch

Out of scope. Do not touch:

• go/toolchain directives in any go.mod. The go directive is a language floor, not a toolchain pin; here it is the input that tells you the test minor.
• The golangci-lint pin (hack/tools.mk on newer branches, hack/tools/go.mod on older ones).
• Non-Go base images (node, alpine), which dependabot does manage.

Phase 1 -- Resolve versions and prepare worktrees

scripts/go-releases.sh answers the version questions; it takes no repo state:

.claude/skills/update-go/scripts/go-releases.sh latest          # ship target
.claude/skills/update-go/scripts/go-releases.sh latest-in 1.26  # test target
.claude/skills/update-go/scripts/go-releases.sh check-tag 1.27.1-trixie

Run check-tag for every <ver>-<variant> combination you intend to write. A Go release can land on go.dev before the Docker Hub image exists, and a missing tag breaks every build on the branch.

scripts/prepare.sh creates the isolated workspaces:

.claude/skills/update-go/scripts/prepare.sh bump-go main release-1.8 release-1.9

It resolves the canonical remote by URL (github.com/akuity/kargo) rather than by name -- upstream is one contributor's convention, not a guarantee -- fetches it, and puts each target branch in its own worktree at <repo>-worktrees/<repo>-<version>, on a fresh feature branch cut from the canonical tip. Branches are therefore current with respect to the real repository by construction; do not merge or rebase afterward. It refuses to reuse a worktree with uncommitted changes. Capture its KEY=value output -- the finish script needs the remote, owner, feature branch, and path.

Phase 2 -- Per branch, classify then edit

In each worktree, independently:

1. Enumerate candidate sites:

   git grep -nIE 'golang:[0-9]+\.[0-9]+|1\.[0-9]{2}\.[0-9]+' \
     -- Dockerfile Dockerfile.dev .github/
   

   Match on the version literal, not on go-version: the setup-go action's ship default sits on a default: line, and a go-version: *anchor reference carries no version of its own.

2. Read the surrounding comment for each hit and assign it a role. If a hit matches no entry in the inventory above, or its comment contradicts the role you would have assigned, stop and ask. A silently misclassified site is the exact failure this skill exists to prevent: a shipped binary built on the capped toolchain still passes CI.

3. Establish the branch's test target: read the root go.mod go directive, take its minor, and resolve latest-in <minor>. Confirm every test site currently sits on that same minor.

4. Rewrite each site to its role's target, preserving the tag variant (-trixie, etc.) and the existing quoting style exactly.

5. Verify: re-grep and confirm every remaining Go version is either the ship target or the test target, and that no site kept an old value. Grep the whole branch for the old version strings to catch a site outside the inventory.

Phase 3 -- Report

Present one table for the whole run, then the diffs:

| Branch       | Role | Current | Target | Sites |
|--------------|------|---------|--------|-------|
| main         | ship | 1.27.0  | 1.27.1 | Dockerfile x2, setup-go action |
| main         | test | 1.27.0  | 1.27.1 | Dockerfile.dev, ci.yaml anchor |
| release-1.8  | ship | 1.27.0  | 1.27.1 | Dockerfile x2, ci.yaml, release.yaml x2 |
| release-1.8  | test | 1.25.14 | 1.25.14 (current) | -- |

Call out separately, without acting on any of it:

• branches whose test minor is behind the latest Go minor, and the golangci-lint upgrade that unblocking would require
• any site whose role you could not determine

Phase 4 -- Leave a finish script

Write bump-go-finish.sh to the primary checkout's root (not a worktree, not /tmp) so it is visible in the editor. Make it executable. Do not run it -- the user commits, pushes, and opens PRs themselves.

The script must, per branch, cd to the worktree and:

1. git commit -s (DCO sign-off is mandatory) with a subject that names what actually moved:

   • both roles, same target: chore(deps): bump Go to <ship>
   • both roles, different targets: chore(deps): bump Go to <ship> and CI Go to <test>
   • ship only: chore(deps): bump Go to <ship> for shipped artifacts
   • test only: chore(deps): bump CI Go to <test>

   End the message with:

   Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
   

2. git push --force-with-lease to the fork remote resolved in Phase 1.

3. Open the PR against the canonical repository:

   gh pr create --repo akuity/kargo \
     --base "<base>" --head "<fork-owner>:<feature-branch>" \
     --title "..." --body-file - --assignee @me \
     --label kind/chore --label area/security \
     --label area/ci-process --label area/release-process \
     --label priority/normal --label dependencies --label docker
   

   Those labels follow the prior art for this change (#6922, #7011). No backport/* label: each branch gets its own PR, so there is nothing to backport. Write PR bodies with one line per paragraph -- GitHub reflows, and hard wraps only make editing harder.

Structure the script so each branch is a self-contained block that can be re-run, with set -euo pipefail at the top and an echo naming each branch as it goes. Skip a branch that already has an open PR for its head, and skip the commit when the worktree is clean, so a partial run can be resumed.

Phase 5 -- Stray dependabot PRs

Dependabot no longer proposes Go bumps, but PRs opened before that exclusion landed can still be open. Check:

gh pr list --repo akuity/kargo --state open --author app/dependabot \
  --json number,title,baseRefName \
  --jq '.[] | select(.title|test("golang")) | "\(.number) (\(.baseRefName)) \(.title)"'

Reference any hit from the corresponding branch's PR body as superseded, and tell the user to close it once the replacement is open. Read its diff first -- say specifically what it got wrong, rather than asserting it was wrong.