Re: [PATCH v4 04/11] commit-reach(paint_down_to_common): prepare for handling shallow commits

> "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
> writes:
>
> > From: Johannes Schindelin <johannes.schindelin@gmx.de>
> >
> > When `git fetch --update-shallow` needs to test for commit ancestry, it
> > can naturally run into a missing object (e.g. if it is a parent of a
> > shallow commit). For the purpose of `--update-shallow`, this needs to be
> > treated as if the child commit did not even have that parent, i.e. the
> > commit history needs to be clamped.
> >
> > For all other scenarios, clamping the commit history is actually a bug,
> > as it would hide repository corruption (for an analysis regarding
> > shallow and partial clones, see the analysis further down).
> >
> > Add a flag to optionally ask the function to ignore missing commits, as
> > `--update-shallow` needs it to, while detecting missing objects as a
> > repository corruption error by default.
> >
> > This flag is needed, and cannot replaced by `is_repository_shallow()` to

> > indicate that situation, because that function would return 0 in the
> > `--update-shallow` scenario: There is not actually a `shallow` file in
> > that scenario, as demonstrated e.g. by t5537.10 ("add new shallow root
> > with receive.updateshallow on") and t5538.4 ("add new shallow root with
> > receive.updateshallow on").
>
> Nicely written.
>
> The description above that has been totally revamped reads much much
> clearer, at least to me, compared to the previous round.