pub fn read(repo: &Path, commit: &str, file: &str) -> Result<String, Trouble>Expand description
One file, as that commit had it.
git show and not a read off the disk: what is wanted is the file at
that commit, and it saves the worktree, which is the expensive part of
everything else here.
Nothing is trimmed. A trim on the way through would eat the trailing
newline git wants and the blank lines above it, and a file that comes back
different from how it went out is an edit that deletes code silently.