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

Stefan Beller [off-list ref] 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 ;-)