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image-automation-controller can lose a push race when many independent ImageUpdateAutomation objects push to the same branch. Recovering cheaply requires catching a working directory up to the new remote tip without a full re-clone, regardless of why the previous push failed. Add FetchAndReset(ctx, branch), which fetches branch via a scoped refspec and hard-resets the current worktree onto the fetched tip, swallowing NoErrAlreadyUpToDate. No changes to the Reader/Writer/Client interfaces; it is a new method on the concrete gogit.Client type. Assisted-by: Claude Sonnet 5/claude-sonnet-5 Signed-off-by: André Bauer <monotek23@gmail.com>
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Why
In deployments with many independent
ImageUpdateAutomation(IUA) objects pushing to the same branch of one GitOps repo (e.g. one IUA per service/region, all on independent reconcile timers), push rejections become common once write concurrency is high enough. Todayimage-automation-controllerhas no in-process retry for a failed push — the next attempt only happens on the next scheduled reconcile, or via controller-runtime's per-item exponential-backoff requeue (750ms doubling, capped at 15min). Under contention, a single IUA can lose several races in a row, each costing a full backoff cycle, turning a sub-minute git operation into a delay of tens of minutes.A companion PR (fluxcd/image-automation-controller#1090) adds a retry-with-backoff loop there, analogous to a
git pull --rebase && git pushretry loop reusing the same local clone across attempts (no re-clone). go-git has no rebase API, so the equivalent here is: fetch (cheap, incremental) → hard-reset onto the new remote tip → let the caller recompute and recommit → push again. That retry loop needs a way to catch a working directory up to the new remote tip without a full re-clone (todaygogit.Clientonly exposesClone, notFetch).What
(*gogit.Client).FetchAndReset(ctx, branch): fetchesbranchfrom the remote via a scoped refspec and hard-resets the current worktree onto the fetched tip. Never touches the remote. Swallows go-git'sNoErrAlreadyUpToDate. MirrorsSwitchBranch's plain(ctx, branchName)signature — no new config struct, since there's exactly one purpose and one caller today.repository.Reader/Writer/Clientinterfaces —image-automation-controllerholds a concrete*gogit.Client, so this is purely an additive new method on the concrete type.Testing
TestFetchAndReset: a stale client with its own unpushed local commit recovers onto the winner's pushed tip, working tree content included; a second call with nothing new is a no-op.make test-gitpasses,go vet/gofmtclean.