Re: [PATCH v4] revision: add `--ignore-missing-links` user option

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 25, 2023, 16:57 UTC
Message-ID: <xmqq5y3yw5qz.fsf@gitster.g>
In-Reply-To: <CAOLa=ZThB0DrRKg98tr7JLu8yPRyDXe_ngkpS3ZfesHQ-f1DLg@mail.gmail.com>

Karthik Nayak <karthik.188@gmail.com> writes:

Show 10 quoted lines

> Let me prefix with saying that I was partly wrong. `--missing` does work for
> trees, only that it's ineffective when used along with the
> `ignore_missing_links` bit.
>
> But for commits, `--missing` was never configured to work with. I
> did a quick look at the code, we can do something like this for
> commits too, i.e.  add support for the `--missing` option. We'll
> have to add a new flag (maybe MISSING) so it can be set during
> within `repo_parse_commit_gently` so we can parse this as a
> missing object in rev-list.c and act accordingly.

Do you mean that process_parents() would now throw such a commit to the resulting list successfully instead of omitting when "--missing" is requested? That sounds like a right thing to do but at the same time is a fix with major impact. I do not offhand know what the ramifications are, for example, when bitmap traversal is in use (I assume such a missing commit would not be catalogued in the bitmap?).

Taylor, what do you think?