A "old ref" of all zeroes is considered a "don't care" ref, and allows
us to say "write the new ref regardless of what the old ref contained
(or even if it existed at all)".

This allows (if git-send-pack were to do it) creating new refs, and
fixing up old ones.

This concludes this lesson.  I've actually successfully sent an update
using the git-send-pack command.

Probably tons of work still to do, and nasty debugging, but it's now
actually potentially useful.

After unpacking the object pack successfully, we go through the list of
refs, and verify that they still contain their expected values.  Then we
replace them with the new ones.

Me tired.

We don't act on them yet, but we parse them.

Right now it just shows which refs it picks up, and whether they are
the same or changed on the remote end. Getting there..

It got turned off by mistake just because I had been doing debugging,
and committed the Makefile that had other changes ...

This patch removes an unnecessary sort from the t6001 testcase.

Sorts were previously necessary when testing non --merge-order cases
because the output order wasn't entirely deterministic unless commit
date was fixed.

However, commit dates are now fixed, so the need for a sort has
disappeared.  So the sort has been removed.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This fix fixes a t/t6001 test case break that was hidden by a bug in the
test case infrastructure.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Junio discovered a problem where an actual test case break was hidden
because pipelines are not handled properly by the test infrastructure in
t6001.

This patch fixes the broken infrastructure (and demonstrates the break
explicitly).

A subsequent patch in this series will fix the test case so that it
doesn't fail.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch makes --merge-order produce the same list as git-rev-list
without --merge-order specified.

In particular, if the graph looks like this:

A
| B
|/
C
|
D

The both git-rev-list B ^A and git-rev-list --merge-order will produce B.

The unit tests have been changed to reflect the fact that the prune
points are now formally part of the start list that is used to perform
the --merge-order sort.

That is: git-rev-list --merge-order A ^D used to produce

= A
| C

It now produces:

^ A
| C
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Added a test case that shows that --merge-order doesn't produce the
correct result in the following case.

A
|
| B
|/
C
|
D

git-rev-list --merge-order A ^B should produce just A. Instead
it produces BCD.

A subsequent patch will fix this defect.
Signed-off-by: NJon Seymour <jon.seymour@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Like git-receive-pack, this is only partway done.

It's not working yet, but it's at the point where I want to be able to
track my changes.  The theory of operation is that this is the "remote"
side of a "git push".  It can tell us what references the remote side
has, receives out reference update commands and a pack-file, and can
execute the unpacking command.

It makes gitk unhappy, and besides, non-merge-order doesn't complain, so
why do it here..

Now you can give git-rev-list tags, trees and blobs, and it will do the
proper reachability for them all. Knock wood.

Of course, you need the "--objects" flag to do anything but plain
commits.

We want to be able to just say "give a difference between these
objects", rather than limiting it to commits only.  This isn't there
yet, but it sets things up to be a bit easier.

It now always read from standard input and rejects non-flag
arguments.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

It can no longer be as verbose, since it doesn't have a good way to
resolve deltas (now that it is purely streaming, it cannot seek around
to read the objects a delta is based on).

But it can check that the thing unpacks cleanly at least as far as pack
syntax goes - all the objects uncompress cleanly, and the pack has the
right final SHA1.

I'd like to add back the "dry-run" thing, but it turns out that to do it
well, I'd have to keep all the object data in memory (which is not
acceptable).  So I'll clean it up a bit and make it do as many checks as
it can.

Given a list of <pack>.idx files, this command validates the
index file and the corresponding .pack file for consistency.

This patch also uses the same validation mechanism in fsck-cache
when the --full flag is used.

During normal operation, sha1_file.c verifies that a given .idx
file matches the .pack file by comparing the SHA1 checksum
stored in .idx file and .pack file as a minimum sanity check.
We may further want to check the pack signature and version when
we map the pack, but that would be a separate patch.

Earlier, errors to map a pack file was not flagged fatal but led
to a random fatal error later.  This version explicitly die()s
when such an error is detected.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

If we prefer 0 as maxsize for diff_delta() to say "unlimited", let's be
consistent about it.

This patch also fixes type mismatch in a call to get_delta_hdr_size()
from packed_delta_info().
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is a wrap-up patch including all the cleanups I've done to the
delta code and its usage.  The most important change is the
factorization of the delta header handling code.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Pointed out by Junio.

This makes it match the new delta encoding, and admittedly makes the
code easier to follow.

This also updates the PACK file version to 2, since this (and the delta
encoding change in the previous commit) are incompatible with the old
format.

Since the delta data format is not tied to any actual git object
anymore, now is the time to add a small improvement to the delta data
header as it is been done for packed object header.  This patch allows
for reducing the delta header of about 2 bytes and makes for simpler
code.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Deltas are useless by themselves and when you use them you need to get
to their base objects.  A base object should inherit recency from the
most recent deltified object that is based on it and that is what this
patch teaches git-pack-objects.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

It gets a bit more complicated to unpack in a streaming environment, but
here it is.  The rewrite is actually a lot cleaner in other ways, it's
just a bit more subtle.

The diff_delta() interface was extended to reject generating too big a
delta while we were working on the packed GIT archive format.

Take advantage of that when generating delta in the similarity estimator
used in diffcore-rename.c
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Standalone unpack-objects command was not adjusted for header length
encoding change when dealing with deltified entry.  This fixes it.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

It's just easier to let git help out with the merge than it is to try to
fix up the diffs.

The fsck-cache complains if objects referred to by files in .git/refs/
or objects stored in files under .git/objects/??/ are not found as
stand-alone SHA1 files (i.e.  found in alternate object pools
GIT_ALTERNATE_OBJECT_DIRECTORIES or packed archives stored under
.git/objects/pack).

Although this is a good semantics to maintain consistency of a single
.git/objects directory as a self contained set of objects, it sometimes
is useful to consider it is OK as long as these "outside" objects are
available.

This commit introduces a new flag, --standalone, to git-fsck-cache.
When it is not specified, connectivity checks and .git/refs pointer
checks are taught that it is OK when expected objects do not exist under
.git/objects/?? hierarchy but are available from an packed archive or in
an alternate object pool.

Another new flag, --full, makes git-fsck-cache to check not only the
current GIT_OBJECT_DIRECTORY but also objects found in alternate object
pools and packed GIT archives.a
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The commands git-fsck-cache and probably git-*-pull needs to have a way
to enumerate objects contained in packed GIT archives and alternate
object pools.  This commit exposes the data structure used to keep track
of them from sha1_file.c, and adds a couple of accessor interface
functions for use by the enhanced git-fsck-cache command.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This was causing random segfaults, because use_packed_git() got
confused by random garbage there.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The fsck-cache complains if objects referred to by files in .git/refs/
or objects stored in files under .git/objects/??/ are not found as
stand-alone SHA1 files (i.e.  found in alternate object pools
GIT_ALTERNATE_OBJECT_DIRECTORIES or packed archives stored under
.git/objects/pack).

Although this is a good semantics to maintain consistency of a single
.git/objects directory as a self contained set of objects, it sometimes
is useful to consider it is OK as long as these "outside" objects are
available.

This commit introduces a new flag, --standalone, to git-fsck-cache.
When it is not specified, connectivity checks and .git/refs pointer
checks are taught that it is OK when expected objects do not exist under
.git/objects/?? hierarchy but are available from an packed archive or in
an alternate object pool.
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This also adds a header with a signature, version info, and the number
of objects to the pack file.  It also encodes the file length and type
more efficiently.

This also suppresses creation of the index file.

We'll use this soon to write pack-files to stdout.