The previous (v3) sync loop betrays my lack of understanding about git.
It tried to codify my archaic mental model (e.g. --branch and --rev
being disting things) and was ultimately a patchwork of corner-cases
evolved over a few years.
This commit is less of a "diff" and more of a "rewrite".
The new logic is simpler and more efficient. It does not `git clone`
ever. It does not differentiate the first sync from subsequent syncs.
It uses `git fetch` to get the exact SHA and then makes a worktree from
that.
The new `--ref` flag replaces both `--rev` and `--branch`, though it
will use those if specified. In fact, almost all of the e2e tests
passed without change - using --ref and --branch!
I will follow this commit up with more cleanups and e2es.
Tim Hockin