Re: [PATCH 07/11] bundle: safely handle --objects option

[Junio C Hamano <gitster@pobox.com>]

"Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com> writes:

> From: Derrick Stolee <derrickstolee@github.com>
>
> Since 'git bundle' uses setup_revisions() to specify the object walk,
> some options do not make sense to include during the pack-objects child
> process. Further, these options are used for a call to
> traverse_commit_list() which would then require a callback which is
> currently NULL.
>
> By populating the callback we prevent a segfault in the case of adding
> the --objects flag. This is really a redundant statement because the
> bundles are constructing a pack-file containing all objects in the
> discovered commit range.
>
> Adding --objects to a 'git bundle' command might cause a slower command,
> but at least it will not have a hard failure when the user supplies this
> option. We can also disable walking trees and blobs in advance of this
> walk.

Wow.  That's fun.  

This commit makes me wonder if we are safe with --max-parents=,
--author=, and other nonsense options, but it is obvious that it is
a segfault waiting to happen by passing NULL to object callback,
which makes it worth singling out "--objects" and dedicate a commit
to fix it.