Re: [PATCH] diff: skip GITLINK when lazy fetching missing objs

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

Jonathan Tan <jonathantanmy@google.com> writes:

> In 7fbbcb21b1 ("diff: batch fetching of missing blobs", 2019-04-08),
> diff was taught to batch the fetching of missing objects when operating
> on a partial clone, but was not taught to refrain from fetching
> GITLINKs. Teach diff to check if an object is a GITLINK before including
> it in the set to be fetched.

OK, so in a lazy repository, running "git diff" (or "git log") could
have resulted in "git fetch" of a history of a submodule, which may
likely have failed?

> (As stated in the commit message of that commit, unpack-trees was also
> taught a similar thing prior, but unpack-trees correctly checks for
> GITLINK before including objects in the set to be fetched.)
> ---

Sign-off?

> One of my colleagues noticed this when switching branches in a
> superproject with a dirty working tree (hence triggering the diff
> mechanism). The test I included in this commit tests a simpler use case,
> but I've verified that this solves my colleague's case too.
> ---
>  diff.c                        |  1 +
>  t/t4067-diff-partial-clone.sh | 31 +++++++++++++++++++++++++++++++
>  2 files changed, 32 insertions(+)
>
> diff --git a/diff.c b/diff.c
> index efe42b341a..e28b463f57 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -6512,6 +6512,7 @@ static void add_if_missing(struct repository *r,
>  			   const struct diff_filespec *filespec)
>  {
>  	if (filespec && filespec->oid_valid &&
> +	    !S_ISGITLINK(filespec->mode) &&
>  	    oid_object_info_extended(r, &filespec->oid, NULL,
>  				     OBJECT_INFO_FOR_PREFETCH))
>  		oid_array_append(to_fetch, &filespec->oid);

Makes sense.

Thanks.