1ee886c1f0
When we try to load an object from disk and fail, our general strategy is to see if we can get it from somewhere else (e.g., a loose object). That lets users fix corruption problems by copying known-good versions of objects into the object database. We already handle the case where we were not able to read the delta from disk. However, when we find that the delta we read does not apply, we simply die. This case is harder to trigger, as corruption in the delta data itself would trigger a crc error from zlib. However, a corruption that pointed us at the wrong delta base might cause it. We can do the same "fail and try to find the object elsewhere" trick instead of dying. This not only gives us a chance to recover, but also puts us on code paths that will alert the user to the problem (with the current message, they do not even know which sha1 caused the problem). Note that unlike some other pack corruptions, we do not recover automatically from this case when doing a repack. There is nothing apparently wrong with the delta, as it points to a valid, accessible object, and we realize the error only when the resulting size does not match up. And in theory, one could even have a case where the corrupted size is the same, and the problem would only be noticed by recomputing the sha1. We can get around this by recomputing the deltas with --no-reuse-delta, which our test does (and this is probably good advice for anyone recovering from pack corruption). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Git - the stupid content tracker
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"git" can mean anything, depending on your mood.
- random three-letter combination that is pronounceable, and not
actually used by any common UNIX command. The fact that it is a
mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the
dictionary of slang.
- "global information tracker": you're in a good mood, and it actually
works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks
Git is a fast, scalable, distributed revision control system with an
unusually rich command set that provides both high-level operations
and full access to internals.
Git is an Open Source project covered by the GNU General Public
License version 2 (some parts of it are under different licenses,
compatible with the GPLv2). It was originally written by Linus
Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
See Documentation/gittutorial.txt to get started, then see
Documentation/everyday.txt for a useful minimum set of commands, and
Documentation/git-commandname.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with "man gittutorial" or "git help tutorial", and the
documentation of each command with "man git-commandname" or "git help
commandname".
CVS users may also want to read Documentation/gitcvs-migration.txt
("man gitcvs-migration" or "git help cvs-migration" if git is
installed).
Many Git online resources are accessible from http://git-scm.com/
including full documentation and Git related tools.
The user discussion and development of Git take place on the Git
mailing list -- everyone is welcome to post bug reports, feature
requests, comments and patches to git@vger.kernel.org (read
Documentation/SubmittingPatches for instructions on patch submission).
To subscribe to the list, send an email with just "subscribe git" in
the body to majordomo@vger.kernel.org. The mailing list archives are
available at http://news.gmane.org/gmane.comp.version-control.git/,
http://marc.info/?l=git and other archival sites.
The maintainer frequently sends the "What's cooking" reports that
list the current status of various development topics to the mailing
list. The discussion following them give a good reference for
project status, development direction and remaining tasks.