From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org, Michael Haggerty <mhagger@alum.mit.edu>
Subject: Re: [PATCH 13/16] prune: keep objects reachable from recent objects
Date: Fri, 03 Oct 2014 20:04:09 -0700 [thread overview]
Message-ID: <xmqqfvf4k02e.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <20141004003036.GE17063@peff.net> (Jeff King's message of "Fri, 3 Oct 2014 20:30:36 -0400")
Jeff King <peff@peff.net> writes:
> On Fri, Oct 03, 2014 at 02:47:57PM -0700, Junio C Hamano wrote:
>
>> With this patch applied, the system will not prune unreachable old
>> objects that are reachable from a recent object (the recent object
>> itself may or may not be reachable but that does not make any
>> difference). And that is sufficient to ensure the integrity of the
>> repository even if you allow new objects to be created reusing any
>> of these unreachable objects that are left behind by prune, because
>> the reachability check done during prune (with this patch applied)
>> makes sure any object left in the repository can safely be used as a
>> starting point of connectivity traversal.
>
> Your use of "safely" in the last sentence here made me think.
>
> In a repository that has had this patch from the beginning, it should be
> safe to traverse the unreachable but unpruned objects, because the
> property of the repository we are trying to guarantee means that we will
> have all of the referents.
> ...
Another case that may be of interest is to start a dumb HTTP commit
walker to fetch new history and kill it before it manages to
complete the graph and update the refs. It has the same property as
running hash-objects to create an unconnected cruft object after you
got your repository into a "safe" state, but it would be a lot less
easier to blame the user for the resulting "breakage".
Perhaps the dumb commit walkers outlived their usefulness and we
should start talking about their deprecation and eventual removal at
a later version of Git?
next prev parent reply other threads:[~2014-10-04 3:04 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-03 20:20 [PATCH 0/16] make prune mtime-checking more careful Jeff King
2014-10-03 20:21 ` [PATCH 01/16] foreach_alt_odb: propagate return value from callback Jeff King
2014-10-03 22:55 ` René Scharfe
2014-10-04 0:31 ` Jeff King
2014-10-03 20:22 ` [PATCH 02/16] isxdigit: cast input to unsigned char Jeff King
2014-10-03 20:22 ` [PATCH 03/16] object_array: factor out slopbuf-freeing logic Jeff King
2014-10-07 11:25 ` Michael Haggerty
2014-10-08 7:36 ` Jeff King
2014-10-08 8:40 ` Michael Haggerty
2014-10-08 8:55 ` Jeff King
2014-10-03 20:22 ` [PATCH 04/16] object_array: add a "clear" function Jeff King
2014-10-03 20:23 ` [PATCH 05/16] clean up name allocation in prepare_revision_walk Jeff King
2014-10-03 20:24 ` [PATCH 06/16] reachable: clear pending array after walking it Jeff King
2014-10-03 20:25 ` [PATCH 07/16] t5304: use test_path_is_* instead of "test -f" Jeff King
2014-10-03 22:12 ` Junio C Hamano
2014-10-03 20:27 ` [PATCH 08/16] t5304: use helper to report failure of "test foo = bar" Jeff King
2014-10-03 22:17 ` Junio C Hamano
2014-10-04 0:13 ` Jeff King
2014-10-07 13:21 ` Michael Haggerty
2014-10-07 17:29 ` Junio C Hamano
2014-10-07 20:18 ` Jeff King
2014-10-07 20:35 ` Junio C Hamano
2014-10-07 21:29 ` Jeff King
2014-10-07 21:53 ` Junio C Hamano
2014-10-07 22:17 ` Michael Haggerty
2014-10-08 1:13 ` Jeff King
2014-10-08 16:58 ` Junio C Hamano
2014-10-07 21:16 ` Junio C Hamano
2014-10-03 20:29 ` [PATCH 09/16] prune: factor out loose-object directory traversal Jeff King
2014-10-03 22:19 ` Junio C Hamano
2014-10-04 0:24 ` Jeff King
2014-10-07 14:07 ` Michael Haggerty
2014-10-08 7:33 ` Jeff King
2014-10-03 20:31 ` [PATCH 10/16] count-objects: do not use xsize_t when counting object size Jeff King
2014-10-03 20:31 ` [PATCH 11/16] count-objects: use for_each_loose_file_in_objdir Jeff King
2014-10-03 20:32 ` [PATCH 12/16] sha1_file: add for_each iterators for loose and packed objects Jeff King
2014-10-05 8:15 ` René Scharfe
2014-10-05 10:47 ` Ramsay Jones
2014-10-03 20:39 ` [PATCH 13/16] prune: keep objects reachable from recent objects Jeff King
2014-10-03 21:47 ` Junio C Hamano
2014-10-04 0:09 ` Jeff King
2014-10-04 0:30 ` Jeff King
2014-10-04 3:04 ` Junio C Hamano [this message]
2014-10-07 16:29 ` Michael Haggerty
2014-10-08 7:19 ` Jeff King
2014-10-08 10:37 ` Michael Haggerty
2014-10-03 20:39 ` [PATCH 14/16] pack-objects: refactor unpack-unreachable expiration check Jeff King
2014-10-03 20:40 ` [PATCH 15/16] pack-objects: match prune logic for discarding objects Jeff King
2014-10-03 20:41 ` [PATCH 16/16] write_sha1_file: freshen existing objects Jeff King
2014-10-03 21:29 ` Junio C Hamano
2014-10-04 0:01 ` Jeff King
2014-10-05 9:12 ` René Scharfe
2014-10-03 22:20 ` [PATCH 0/16] make prune mtime-checking more careful Junio C Hamano
2014-10-04 22:22 ` Junio C Hamano
2014-10-05 9:19 ` René Scharfe
2014-10-06 1:42 ` Jeff King
2014-10-08 8:31 ` Jeff King
2014-10-08 17:03 ` Junio C Hamano
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