backup property
Whether to snapshot the index and working tree before the tasks run and roll back to it when the hook fails.
Tasks edit files in place, so a task that rewrites a file during a run
that later fails would otherwise leave those edits behind with no way to
undo them. With backup enabled a failed hook leaves the repository
exactly as it found it. Defaults to true.
Untracked files are never rolled back, and the snapshot is kept at
refs/hooksman/backup until the hook succeeds, so work is still
recoverable by hand if the hook is killed before it can restore.
Implementation
final bool backup;