git

Overview ¶

Package git provides an errs.Classifier for failures from Git processes.

Git has no typed status to read: it reports almost everything as a non-zero exit and a line of prose, so a connection reset and a deleted branch both leave `git fetch` looking identical to a caller that only checks the code. The subcommand that was run and the diagnostic git printed are therefore the only signals available, and the classification pairs them: a fragment is evidence of a transient failure only for the operations it can actually arise from, so a transport fault counts against a command that talks to the remote and lock contention counts against any command that writes to the checkout.

Only a recognised pair is retryable. Everything else is a permanent infrastructure failure, including a diagnostic this package has never seen. The direction is deliberate: an unlisted transient failure costs one lost retry, while a permanent failure that defaulted to retryable would replay a deterministic error — a deleted target branch, an empty squash commit, a rejected push — through the whole retry budget, re-running the fetch, reset and cherry-picks behind it each time, before dead-lettering anyway.

Git's wording drifts between versions, so the fragment lists are expected to grow. Adding one is cheap and safe; the cost of a missing fragment is bounded at a single lost retry, which is what makes the allowlist maintainable.

Cancellation is deliberately absent. A git process killed because its context ended dies with "signal: killed" and no trace of the cancellation, so it is gitexec.CommandFailure — not this classifier — that puts context.Canceled back in the chain, leaving the generic classifier to recognise it as it does for every other cancelled operation.