Re: [PATCH v4 2/8] sha1_file: rename LOOKUP_UNKNOWN_OBJECT

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

Jonathan Tan <jonathantanmy@google.com> writes:

> The LOOKUP_UNKNOWN_OBJECT flag was introduced in commit 46f0344
> ("sha1_file: support reading from a loose object of unknown type",
> 2015-05-03) in order to support a feature in cat-file subsequently
> introduced in commit 39e4ae3 ("cat-file: teach cat-file a
> '--allow-unknown-type' option", 2015-05-03). Despite its name and
> location in cache.h, this flag is used neither in
> read_sha1_file_extended() nor in any of the lookup functions, but used
> only in sha1_object_info_extended().
>
> Therefore rename this flag to OBJECT_INFO_ALLOW_UNKNOWN_TYPE, taking the
> name of the cat-file flag that invokes this feature, and move it closer
> to the declaration of sha1_object_info_extended(). Also add
> documentation for this flag.

All of the above makes sense, but ...

> diff --git a/cache.h b/cache.h
> index 4d92aae0e..e2ec45dfe 100644
> --- a/cache.h
> +++ b/cache.h
> @@ -1207,7 +1207,6 @@ extern char *xdg_cache_home(const char *filename);
>  
>  /* object replacement */
>  #define LOOKUP_REPLACE_OBJECT 1
> -#define LOOKUP_UNKNOWN_OBJECT 2
>  extern void *read_sha1_file_extended(const unsigned char *sha1, enum object_type *type, unsigned long *size, unsigned flag);
>  static inline void *read_sha1_file(const unsigned char *sha1, enum object_type *type, unsigned long *size)
>  {
> @@ -1866,6 +1865,8 @@ struct object_info {
>   */
>  #define OBJECT_INFO_INIT {NULL}
>  
> +/* Allow reading from a loose object file of unknown/bogus type */
> +#define OBJECT_INFO_ALLOW_UNKNOWN_TYPE 2

... this contradicts the analysis given, doesn't it?

Does something break if we change this to 1 (perhaps because in some
cases this bit reach read_sha1_file_extended())?  I doubt it, but
leaving this to still define the bit to 2 makes readers wonder why.