Re: [PATCH 2/7] odb/source-inmemory: signal missing objects via positive return

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

Patrick Steinhardt <ps@pks.im> writes:

> The in-memory source returns a negative value from its
> `read_object_info()` callback when the object in question does not
> exist. Adapt the callback to return a positive value for missing objects
> according to the new calling convention.
>
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
>  odb/source-inmemory.c         | 2 +-
>  t/unit-tests/u-odb-inmemory.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/odb/source-inmemory.c b/odb/source-inmemory.c
> index 3e71611b8e..57183daf4d 100644
> --- a/odb/source-inmemory.c
> +++ b/odb/source-inmemory.c
> @@ -66,7 +66,7 @@ static int odb_source_inmemory_read_object_info(struct odb_source *source,
>  
>  	object = find_cached_object(inmemory, oid);
>  	if (!object)
> -		return -1;
> +		return 1;

Let's not define "any positive value means this single thing: it
does not exist" and then return a mysterious and unspecified hard
coded constant like this.  Instead perhaps something along this
line?

    enum odb_roi_status {
	ODB_ROI_SUCCESS = 0,
	ODB_ROI_MISSING = 1,
	ODB_ROI_IO_ERROR = -1,
	...
    };

As I already said, I personally prefer to define MISSING also as
a negative value.