Re: [PATCH 2/2] repack -ad: prune the list of shallow commits

>
> On Fri, Jul 13, 2018 at 10:19 PM Johannes Schindelin via GitGitGadget
> <gitgitgadget@gmail.com> wrote:
> >
> > From: Johannes Schindelin <johannes.schindelin@gmx.de>
> >
> > While it is true that we never add unreachable commits into pack files
> > intentionally (as `git repack`'s documentation states), we must not
> > forget that a `git fetch --prune` (or even a `git fetch` when a ref was
> > force-pushed in the meantime) can make a commit unreachable that was
> > reachable before.
> >
> > Therefore it is not safe to assume that a `git repack -adlf` will keep
> > unreachable commits alone (under the assumption that they had not been
> > packed in the first place).
> >
> > This is particularly important to keep in mind when looking at the
> > `.git/shallow` file: if any commits listed in that file become
> > unreachable, it is not a problem, but if they go missing, it *is* a
> > problem. One symptom of this problem is that a deepening fetch may now
> > fail with
> >
> >         fatal: error in object: unshallow <commit-hash>
> >
>
> Could you elaborate a bit more?