Re: [PATCH v2] list-objects.c: don't segfault for missing cmdline objects

> When a command is invoked with both --exclude-promisor-objects,
> --objects-edge-aggressive, and a missing object on the command line,
> the rev_info.cmdline array could get a NULL pointer for the value of
> an 'item' field. Prevent dereferencing of a NULL pointer in that
> situation.

> There are a few other places in the code where rev_info.cmdline is read
> and the code doesn't handle NULL objects, but I couldn't prove to myself
> that any of them needed to change except this one (since it may not
> actually be possible to reach the other code paths with
> rev_info.cmdline[] set to NULL).
>
> Signed-off-by: Matthew DeVore <matvore@google.com>
> ---
>  list-objects.c           | 3 ++-
>  t/t0410-partial-clone.sh | 6 +++++-
>  2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/list-objects.c b/list-objects.c
> index c41cc80db5..27ed2c6cab 100644
> --- a/list-objects.c
> +++ b/list-objects.c
> @@ -245,7 +245,8 @@ void mark_edges_uninteresting(struct rev_info *revs, show_edge_fn show_edge)
>  		for (i = 0; i < revs->cmdline.nr; i++) {
>  			struct object *obj = revs->cmdline.rev[i].item;
>  			struct commit *commit = (struct commit *)obj;
> -			if (obj->type != OBJ_COMMIT || !(obj->flags & UNINTERESTING))
> +			if (!obj || obj->type != OBJ_COMMIT ||
> +			    !(obj->flags & UNINTERESTING))
>  				continue;
>  			mark_tree_uninteresting(revs->repo,
>  						get_commit_tree(commit));
> diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
> index ba3887f178..e52291e674 100755
> --- a/t/t0410-partial-clone.sh
> +++ b/t/t0410-partial-clone.sh
> @@ -366,7 +366,11 @@ test_expect_success 'rev-list accepts missing and promised objects on command li
>  
>  	git -C repo config core.repositoryformatversion 1 &&
>  	git -C repo config extensions.partialclone "arbitrary string" &&
> -	git -C repo rev-list --exclude-promisor-objects --objects "$COMMIT" "$TREE" "$BLOB"
> +
> +	git -C repo rev-list --objects \
> +		--exclude-promisor-objects "$COMMIT" "$TREE" "$BLOB" &&
> +	git -C repo rev-list --objects-edge-aggressive \
> +		--exclude-promisor-objects "$COMMIT" "$TREE" "$BLOB"
>  '
>  
>  test_expect_success 'gc repacks promisor objects separately from non-promisor objects' '