Re: fact-import: failed to apply delta

> Junio C Hamano <gitster@pobox.com> writes:
> 
> > "Shawn O. Pearce" <spearce@spearce.org> writes:
> >
> >> Daniel Barkalow <barkalow@iabervon.org> wrote:
> >>> On Tue, 10 Feb 2009, Shawn O. Pearce wrote:
> >>> > 
> >>> > We should dump the cached_objects table in sha1_file.c during
> >>> > a checkpoint in fast-import.
> >>> 
> >>> No, that one's keyed by sha1, and doesn't get collisions; it's the 
> >>> delta_base_cache that's the issue; it's keyed by struct packed_git * and 
> >>> offset.
> >>
> >> Uh, yea, I realize that after I sent the message.  Does this patch
> >> fix it for you?
> >>
> >> --8<--
> >> Clear the delta base cache during fast-import checkpoint
> >>
> >> Otherwise we may reuse the same memory address for a totally
> >> different "struct packed_git", and a previously cached object from
> >> the prior occupant might be returned when trying to unpack an object
> >> from the new pack.
> >
> > Can this be made more automatic?
> >
> > For example if you do this every time a new pack is installed to
> > sha1_file(), like in add_packed_git() perhaps, wouldn't that be much less
> > error prone?
> 
> On second thought, I think fast-import is the only program that plays
> funny games of feeding a packed_git that is *not* part of the real list of
> packed_git installed in the system to unpack_entry(), so probably your
> patch is a better idea.