Re: [PATCH] RFC: git lazy clone proof-of-concept

Nicolas Pitre <nico@cam.org> wrote:

Please don't.

Obtaining the SHA-1 of your delta base would require unpacking your delta base and then doing a SHA-1 hash of it. Or alternatively doing a search through the .idx for the object that starts at the requested OFS. Either way, its really expensive for a minor detail of output in verify-pack. Something that any script can produce with a simple reverse lookup table.

Its also run after we just spent a hell of a lot of time and disk IO trying to verify the packfile. We slammed through the pack once to do its overall SHA-1, and then god knows how many times as we iterate the objects in pack order, not delta base order, thus causing the delta base cache to become overwhelmed and constantly fault out entries. Pack verification is stupid and slow. This would make -v even worse.

But if you are going to do that, you may also want to fix the "*store_size = 0 /* notyet */" that's like 5 lines above. :)

BTW, why does this return const char* from typename(type) instead of just returning the enum object_type and letting the caller do typename() if they want it? Most of our other code that returns types returns the enum, not the string. :-\