Re: [PATCH] send-pack: never fetch when checking exclusions

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 8, 2019, 04:10 UTC
Message-ID: <xmqqzhibnahi.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20191007213839.233451-1-jonathantanmy@google.com>

Jonathan Tan <jonathantanmy@google.com> writes:

Show 5 quoted lines

> When building the packfile to be sent, send_pack() is given a list of
> remote refs to be used as exclusions. For each ref, it first checks if
> the ref exists locally, and if it does, passes it with a "^" prefix to
> pack-objects. However, in a partial clone, the check may trigger a lazy
> fetch. Ensure that this lazy fetch does not occur.

Is there any effect worth describing here, other than the obvious "we do not lazily fetch from within the has_object_file() function"?

For example, would this change mean that the resulting pack may include stuff that are reachable from the (missing) negative objects that would not otherwise have to be sent if these objects were available (or made available by the lazy fetching), and we are making a trade-off to send possibly more in order for not fetching? Have we laid enough on the table to help readers if such a trade-off (if we are making one, that is) strikes the right balance?

Thanks.

Show 19 quoted lines

> Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
> ---
>  send-pack.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/send-pack.c b/send-pack.c
> index 6dc16c3211..34c77cbb1a 100644
> --- a/send-pack.c
> +++ b/send-pack.c
> @@ -40,7 +40,8 @@ int option_parse_push_signed(const struct option *opt,
>  
>  static void feed_object(const struct object_id *oid, FILE *fh, int negative)
>  {
> -	if (negative && !has_object_file(oid))
> +	if (negative &&
> +	    !has_object_file_with_flags(oid, OBJECT_INFO_SKIP_FETCH_OBJECT))
>  		return;
>  
>  	if (negative)