Re: [PATCH 05/27] object-store: move packed_git and packed_git_mru to object store

> Stefan Beller <sbeller@google.com> writes:
>
>> +
>> +/*
>> + * The mru list_head is supposed to be initialized using
>> + * the LIST_HEAD macro, assigning prev/next to itself.
>> + * However this doesn't work in this case as some compilers dislike
>> + * that macro on member variables. Use NULL instead as that is defined
>> + * and accepted, deferring the real init to prepare_packed_git_mru(). */
>> +#define __MRU_INIT { NULL, NULL }
>> +#define RAW_OBJECT_STORE_INIT { NULL, NULL, __MRU_INIT, NULL, NULL }
>
> I do not think it has to be this way to abuse two NULLs, if you
> faithfully mimicked how LIST_HEAD() macro is constructed.  The
> reason why it does not try to introduce
>
>         struct list_head x = LIST_HEAD_INIT;
>
> and instead, uses
>
>         LIST_HEAD(x);
>
> is because of the need for self referral.  If we learn from it, we
> can do the same, i.e. instead of doing
>
>         struct raw_object_store x = RAW_OBJECT_STORE_INIT;
>
> we can do
>
>         RAW_OBJECT_STORE(x);
>
> that expands to
>
>         struct raw_object_store x = {
>                 ...
>                 { &x.packed_git_mru, &x.packed_git_mru },
>                 ...
>         };
>
> no?  Then we do not need such a lengthy comment that reads only like
> an excuse ;-)