A Git-aware "connect" transport allows the "transport_take_over" to
redirect generic transport requests like fetch(), push_refs() and
get_refs_list() to the native Git transport handling methods. The
take-over process replaces transport->data with a fake data that
these method implementations understand.
While this hack works OK for a single request, it breaks when the
transport needs to make more than one requests. transport->data
that used to hold necessary information for the specific helper to
work correctly is destroyed during the take-over process.
One codepath that this matters is "git fetch" in auto-follow mode;
when it does not get all the tags that ought to point at the history
it got (which can be determined by looking at the peeled tags in the
initial advertisement) from the primary transfer, it internally
makes a second request to complete the fetch. Because "take-over"
hack has already destroyed the data necessary to talk to the
transport helper by the time this happens, the second request cannot
make a request to the helper to make another connection to fetch
these additional tags.
Mark such a transport as "cannot_reuse", and use a separate
transport to perform the backfill fetch in order to work around
this breakage.
Note that this problem does not manifest itself when running t5802,
because our upload-pack gives you all the necessary auto-followed
tags during the primary transfer. You would need to step through
"git fetch" in a debugger, stop immediately after the primary
transfer finishes and writes these auto-followed tags, remove the
tag references and repack/prune the repository to convince the
"find-non-local-tags" procedure that the primary transfer failed to
give us all the necessary tags, and then let it continue, in order
to trigger the bug in the secondary transfer this patch fixes.
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.
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