Граф коммитов

608 Коммитов

Автор SHA1 Сообщение Дата
Linus Torvalds 7dff9b30ea Support 'raw' date format
Talking about --date, one thing I wanted for the 1234567890 date was to
get things in the raw format. Sure, you get them with --pretty=raw, but it
felt a bit sad that you couldn't just ask for the date in raw format.

So here's a throw-away patch (meaning: I won't be re-sending it, because I
really don't think it's a big deal) to add "--date=raw". It just prints
out the internal raw git format - seconds since epoch plus timezone (put
another way: 'date +"%s %z"' format)

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-20 21:45:42 -08:00
Junio C Hamano 8c5b85ce87 Merge branch 'maint'
* maint:
  More friendly message when locking the index fails.
  Document git blame --reverse.
  Documentation: Note file formats send-email accepts
2009-02-19 23:44:07 -08:00
Matthieu Moy e43a6fd3e9 More friendly message when locking the index fails.
Just saying that index.lock exists doesn't tell the user _what_ to do
to fix the problem. We should give an indication that it's normally
safe to delete index.lock after making sure git isn't running here.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-19 23:22:57 -08:00
Johannes Schindelin 4fcc86b07d Introduce the function strip_path_suffix()
The function strip_path_suffix() will try to strip a given suffix from
a given path.  The suffix must start at a directory boundary (i.e. "core"
is not a path suffix of "libexec/git-core", but "git-core" is).

Arbitrary runs of directory separators ("slashes") are assumed identical.

Example:

	strip_path_suffix("C:\\msysgit/\\libexec\\git-core",
		"libexec///git-core", &prefix)

will set prefix to "C:\\msysgit" and return 0.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-19 22:45:48 -08:00
Junio C Hamano 160d2bc353 Merge branch 'ms/mailmap'
* ms/mailmap:
  Move mailmap documentation into separate file
  Change current mailmap usage to do matching on both name and email of author/committer.
  Add map_user() and clear_mailmap() to mailmap
  Add find_insert_index, insert_at_index and clear_func functions to string_list
  Add mailmap.file as configurational option for mailmap location
2009-02-15 01:44:15 -08:00
Junio C Hamano 954cfb5cfd Revert "Merge branch 'js/notes'"
This reverts commit 7b75b331f6, reversing
changes made to 5d680a67d7.
2009-02-10 21:32:10 -08:00
Junio C Hamano 6e5d7ddc49 Merge branch 'js/maint-1.6.0-path-normalize'
* js/maint-1.6.0-path-normalize:
  Remove unused normalize_absolute_path()
  Test and fix normalize_path_copy()
  Fix GIT_CEILING_DIRECTORIES on Windows
  Move sanitary_path_copy() to path.c and rename it to normalize_path_copy()
  Make test-path-utils more robust against incorrect use
2009-02-10 21:30:52 -08:00
Junio C Hamano fd8475d9fb Merge branch 'maint'
* maint:
  Clear the delta base cache during fast-import checkpoint
2009-02-10 21:30:45 -08:00
Junio C Hamano 9b27ea9518 Merge branch 'maint-1.6.0' into maint
* maint-1.6.0:
  Clear the delta base cache during fast-import checkpoint
2009-02-10 15:32:26 -08:00
Shawn O. Pearce 3d20c636af 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.

Found-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-10 15:30:59 -08:00
Marius Storm-Olsen d551a48816 Add mailmap.file as configurational option for mailmap location
This allows us to augment the repo mailmap file, and to use
mailmap files elsewhere than the repository root. Meaning
that the entries in mailmap.file will override the entries
in "./.mailmap", should they match.

Signed-off-by: Marius Storm-Olsen <marius@trolltech.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-08 12:36:26 -08:00
Johannes Sixt f2a782b8ba Remove unused normalize_absolute_path()
This function is now superseded by normalize_path_copy().

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-07 12:23:30 -08:00
Johannes Sixt f3cad0ad82 Move sanitary_path_copy() to path.c and rename it to normalize_path_copy()
This function and normalize_absolute_path() do almost the same thing. The
former already works on Windows, but the latter crashes.

In subsequent changes we will remove normalize_absolute_path(). Here we
make the replacement function reusable. On the way we rename it to reflect
that it does some path normalization. Apart from that this is only moving
around code.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-07 12:23:29 -08:00
Junio C Hamano 7b75b331f6 Merge branch 'js/notes'
* js/notes:
  git-notes: fix printing of multi-line notes
  notes: fix core.notesRef documentation
  Add an expensive test for git-notes
  Speed up git notes lookup
  Add a script to edit/inspect notes
  Introduce commit notes

Conflicts:
	pretty.c
2009-02-05 19:40:39 -08:00
Junio C Hamano 141b6b83d7 Merge branch 'lt/maint-wrap-zlib' into maint
* lt/maint-wrap-zlib:
  Wrap inflate and other zlib routines for better error reporting

Conflicts:
	http-push.c
	http-walker.c
	sha1_file.c
2009-02-05 18:01:00 -08:00
Junio C Hamano 8712b3cdb0 Merge branch 'tr/previous-branch'
* tr/previous-branch:
  t1505: remove debugging cruft
  Simplify parsing branch switching events in reflog
  Introduce for_each_recent_reflog_ent().
  interpret_nth_last_branch(): plug small memleak
  Fix reflog parsing for a malformed branch switching entry
  Fix parsing of @{-1}@{1}
  interpret_nth_last_branch(): avoid traversing the reflog twice
  checkout: implement "-" abbreviation, add docs and tests
  sha1_name: support @{-N} syntax in get_sha1()
  sha1_name: tweak @{-N} lookup
  checkout: implement "@{-N}" shortcut name for N-th last branch

Conflicts:
	sha1_name.c
2009-01-28 15:00:27 -08:00
Junio C Hamano 0990e7aaaa Merge branch 'kb/lstat-cache'
* kb/lstat-cache:
  lstat_cache(): introduce clear_lstat_cache() function
  lstat_cache(): introduce invalidate_lstat_cache() function
  lstat_cache(): introduce has_dirs_only_path() function
  lstat_cache(): introduce has_symlink_or_noent_leading_path() function
  lstat_cache(): more cache effective symlink/directory detection
2009-01-25 17:13:34 -08:00
Junio C Hamano d64d4835b8 Merge branch 'cb/add-pathspec'
* cb/add-pathspec:
  remove pathspec_match, use match_pathspec instead
  clean up pathspec matching
2009-01-25 17:13:11 -08:00
Junio C Hamano 36dd939393 Merge branch 'lt/maint-wrap-zlib'
* lt/maint-wrap-zlib:
  Wrap inflate and other zlib routines for better error reporting

Conflicts:
	http-push.c
	http-walker.c
	sha1_file.c
2009-01-21 16:55:17 -08:00
Kjetil Barvik bda6eb0da9 lstat_cache(): introduce clear_lstat_cache() function
If you want to completely clear the contents of the lstat_cache(), then
call this new function.

Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-18 13:58:34 -08:00
Kjetil Barvik aeabab5c71 lstat_cache(): introduce invalidate_lstat_cache() function
In some cases it could maybe be necessary to say to the cache that
"Hey, I deleted/changed the type of this pathname and if you currently
have it inside your cache, you should deleted it".

This patch introduce a function which support this.

Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-18 13:58:31 -08:00
Kjetil Barvik bad4a54fa6 lstat_cache(): introduce has_dirs_only_path() function
The create_directories() function in entry.c currently calls stat()
or lstat() for each path component of the pathname 'path' each and every
time.  For the 'git checkout' command, this function is called on each
file for which we must do an update (ce->ce_flags & CE_UPDATE), so we get
lots and lots of calls.

To fix this, we make a new wrapper to the lstat_cache() function, and
call the wrapper function instead of the calls to the stat() or the
lstat() functions.  Since the paths given to the create_directories()
function, is sorted alphabetically, the new wrapper would be very
cache effective in this situation.

To support it we must update the lstat_cache() function to be able to
say that "please test the complete length of 'name'", and also to give
it the length of a prefix, where the cache should use the stat()
function instead of the lstat() function to test each path component.

Thanks to Junio C Hamano, Linus Torvalds and Rene Scharfe for valuable
comments to this patch!

Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-18 13:54:54 -08:00
Kjetil Barvik 09c9306658 lstat_cache(): introduce has_symlink_or_noent_leading_path() function
In some cases, especially inside the unpack-trees.c file, and inside
the verify_absent() function, we can avoid some unnecessary calls to
lstat(), if the lstat_cache() function can also be told to keep track
of non-existing directories.

So we update the lstat_cache() function to handle this new fact,
introduce a new wrapper function, and the result is that we save lots
of lstat() calls for a removed directory which previously contained
lots of files, when we call this new wrapper of lstat_cache() instead
of the old one.

We do similar changes inside the unlink_entry() function, since if we
can already say that the leading directory component of a pathname
does not exist, it is not necessary to try to remove a pathname below
it!

Thanks to Junio C Hamano, Linus Torvalds and Rene Scharfe for valuable
comments to this patch!

Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-18 13:54:49 -08:00
Junio C Hamano ae5a6c3684 checkout: implement "@{-N}" shortcut name for N-th last branch
Implement a shortcut @{-N} for the N-th last branch checked out, that
works by parsing the reflog for the message added by previous
git-checkout invocations.  We expand the @{-N} to the branch name, so
that you end up on an attached HEAD on that branch.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-17 18:36:49 -08:00
Clemens Buchacher 0b50922abf remove pathspec_match, use match_pathspec instead
Both versions have the same functionality. This removes any
redundancy.

This also adds makes two extensions to match_pathspec:

- If pathspec is NULL, return 1. This reflects the behavior of git
  commands, for which no paths usually means "match all paths".

- If seen is NULL, do not use it.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-14 19:18:44 -08:00
Christian Couder c2c5b27051 sha1_file: make "read_object" static
This function is only used from "sha1_file.c".

And as we want to add a "replace_object" hook in "read_sha1_file",
we must not let people bypass the hook using something other than
"read_sha1_file".

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-13 00:14:55 -08:00
Linus Torvalds 39c68542fc Wrap inflate and other zlib routines for better error reporting
R. Tyler Ballance reported a mysterious transient repository corruption;
after much digging, it turns out that we were not catching and reporting
memory allocation errors from some calls we make to zlib.

This one _just_ wraps things; it doesn't do the "retry on low memory
error" part, at least not yet. It is an independent issue from the
reporting.  Some of the errors are expected and passed back to the caller,
but we die when zlib reports it failed to allocate memory for now.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-11 02:13:06 -08:00
Johannes Schindelin 879ef2485d Introduce commit notes
Commit notes are blobs which are shown together with the commit
message.  These blobs are taken from the notes ref, which you can
configure by the config variable core.notesRef, which in turn can
be overridden by the environment variable GIT_NOTES_REF.

The notes ref is a branch which contains "files" whose names are
the names of the corresponding commits (i.e. the SHA-1).

The rationale for putting this information into a ref is this: we
want to be able to fetch and possibly union-merge the notes,
maybe even look at the date when a note was introduced, and we
want to store them efficiently together with the other objects.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-12-21 02:47:21 -08:00
Junio C Hamano de0db42278 Merge branch 'maint'
* maint:
  fsck: reduce stack footprint
  make sure packs to be replaced are closed beforehand
2008-12-11 00:36:31 -08:00
Nicolas Pitre c74faea19e make sure packs to be replaced are closed beforehand
Especially on Windows where an opened file cannot be replaced, make
sure pack-objects always close packs it is about to replace. Even on
non Windows systems, this could save potential bad results if ever
objects were to be read from the new pack file using offset from the old
index.

This should fix t5303 on Windows.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Tested-by: Johannes Sixt <j6t@kdbg.org> (MinGW)
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-12-10 17:56:05 -08:00
Junio C Hamano 0fd9d7e66d Merge branch 'bc/maint-keep-pack' into maint
* bc/maint-keep-pack:
  repack: only unpack-unreachable if we are deleting redundant packs
  t7700: test that 'repack -a' packs alternate packed objects
  pack-objects: extend --local to mean ignore non-local loose objects too
  sha1_file.c: split has_loose_object() into local and non-local counterparts
  t7700: demonstrate mishandling of loose objects in an alternate ODB
  builtin-gc.c: use new pack_keep bitfield to detect .keep file existence
  repack: do not fall back to incremental repacking with [-a|-A]
  repack: don't repack local objects in packs with .keep file
  pack-objects: new option --honor-pack-keep
  packed_git: convert pack_local flag into a bitfield and add pack_keep
  t7700: demonstrate mishandling of objects in packs with a .keep file
2008-12-02 23:00:04 -08:00
Junio C Hamano 388b2acd6e git add --intent-to-add: fix removal of cached emptiness
This uses the extended index flag mechanism introduced earlier to mark
the entries added to the index via "git add -N" with CE_INTENT_TO_ADD.

The logic to detect an "intent to add" entry for the purpose of allowing
"git rm --cached $path" is tightened to check not just for a staged empty
blob, but with the CE_INTENT_TO_ADD bit.  This protects an empty blob that
was explicitly added and then modified in the work tree from being dropped
with this sequence:

	$ >empty
	$ git add empty
	$ echo "non empty" >empty
	$ git rm --cached empty

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-11-28 19:58:24 -08:00
Junio C Hamano fe60dff744 Merge branch 'nd/narrow' (early part) into jc/add-i-t-a
* 'nd/narrow' (early part):
  Extend index to save more flags
2008-11-28 17:22:35 -08:00
Junio C Hamano 2af9664776 Merge branch 'lt/preload-lstat'
* lt/preload-lstat:
  Fix index preloading for racy dirty case
  Add cache preload facility
2008-11-27 19:24:13 -08:00
Junio C Hamano 47a792539a Merge branch 'jk/commit-v-strip'
* jk/commit-v-strip:
  status: show "-v" diff even for initial commit
  wt-status: refactor initial commit printing
  define empty tree sha1 as a macro
2008-11-16 00:48:59 -08:00
Linus Torvalds 671c9b7e31 Add cache preload facility
This can do the lstat() storm in parallel, giving potentially much
improved performance for cold-cache cases or things like NFS that have
weak metadata caching.

Just use "read_cache_preload()" instead of "read_cache()" to force an
optimistic preload of the index stat data.  The function takes a
pathspec as its argument, allowing us to preload only the relevant
portion of the index.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-11-14 19:11:49 -08:00
Junio C Hamano 7b51b77dbc Merge branch 'np/pack-safer'
* np/pack-safer:
  t5303: fix printf format string for portability
  t5303: work around printf breakage in dash
  pack-objects: don't leak pack window reference when splitting packs
  extend test coverage for latest pack corruption resilience improvements
  pack-objects: allow "fixing" a corrupted pack without a full repack
  make find_pack_revindex() aware of the nasty world
  make check_object() resilient to pack corruptions
  make packed_object_info() resilient to pack corruptions
  make unpack_object_header() non fatal
  better validation on delta base object offsets
  close another possibility for propagating pack corruption
2008-11-12 22:26:35 -08:00
Junio C Hamano ecbbfb15a4 Merge branch 'bc/maint-keep-pack'
* bc/maint-keep-pack:
  t7700: test that 'repack -a' packs alternate packed objects
  pack-objects: extend --local to mean ignore non-local loose objects too
  sha1_file.c: split has_loose_object() into local and non-local counterparts
  t7700: demonstrate mishandling of loose objects in an alternate ODB
  builtin-gc.c: use new pack_keep bitfield to detect .keep file existence
  repack: do not fall back to incremental repacking with [-a|-A]
  repack: don't repack local objects in packs with .keep file
  pack-objects: new option --honor-pack-keep
  packed_git: convert pack_local flag into a bitfield and add pack_keep
  t7700: demonstrate mishandling of objects in packs with a .keep file
2008-11-12 22:00:43 -08:00
Junio C Hamano 6cd3729eae Merge branch 'maint'
* maint:
  Start 1.6.0.5 cycle
  Fix pack.packSizeLimit and --max-pack-size handling
  checkout: Fix "initial checkout" detection
  Remove the period after the git-check-attr summary

Conflicts:
	RelNotes
2008-11-12 15:03:57 -08:00
Junio C Hamano fa7b3c2f75 checkout: Fix "initial checkout" detection
Earlier commit 5521883 (checkout: do not lose staged removal, 2008-09-07)
tightened the rule to prevent switching branches from losing local
changes, so that staged removal of paths can be protected, while
attempting to keep a loophole to still allow a special case of switching
out of an un-checked-out state.

However, the loophole was made a bit too tight, and did not allow
switching from one branch (in an un-checked-out state) to check out
another branch.

The change to builtin-checkout.c in this commit loosens it to allow this,
by not insisting the original commit and the new commit to be the same.

It also introduces a new function, is_index_unborn (and an associated
macro, is_cache_unborn), to check if the repository is truly in an
un-checked-out state more reliably, by making sure that $GIT_INDEX_FILE
did not exist when populating the in-core index structure.  A few places
the earlier commit 5521883 added the check for the initial checkout
condition are updated to use this function.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-11-12 14:16:50 -08:00
Jeff King 14d9c57896 define empty tree sha1 as a macro
This can potentially be used in a few places, so let's make
it available to all parts of the code.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-11-12 12:52:21 -08:00
Brandon Casey 0f4dc14ac4 sha1_file.c: split has_loose_object() into local and non-local counterparts
Signed-off-by: Brandon Casey <drafnel@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-11-12 10:29:22 -08:00
Brandon Casey 8d25931d6f packed_git: convert pack_local flag into a bitfield and add pack_keep
pack_keep will be set when a pack file has an associated .keep file.

Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-11-12 10:28:08 -08:00
Junio C Hamano 8b1981d32b Merge branch 'ar/maint-mksnpath' into maint
* ar/maint-mksnpath:
  Use git_pathdup instead of xstrdup(git_path(...))
  git_pathdup: returns xstrdup-ed copy of the formatted path
  Fix potentially dangerous use of git_path in ref.c
  Add git_snpath: a .git path formatting routine with output buffer
  Fix potentially dangerous uses of mkpath and git_path
  Fix mkpath abuse in dwim_ref and dwim_log of sha1_name.c
  Add mksnpath which allows you to specify the output buffer

Conflicts:
	builtin-revert.c
	rerere.c
2008-11-08 16:13:19 -08:00
Junio C Hamano 3b8572a429 Merge branch 'mv/maint-branch-m-symref' into maint
* mv/maint-branch-m-symref:
  update-ref --no-deref -d: handle the case when the pointed ref is packed
  git branch -m: forbid renaming of a symref
  Fix git update-ref --no-deref -d.
  rename_ref(): handle the case when the reflog of a ref does not exist
  Fix git branch -m for symrefs.
2008-11-08 16:07:37 -08:00
Junio C Hamano a1a846a19e Merge branch 'ar/mksnpath'
* ar/mksnpath:
  Use git_pathdup instead of xstrdup(git_path(...))
  git_pathdup: returns xstrdup-ed copy of the formatted path
  Fix potentially dangerous use of git_path in ref.c
  Add git_snpath: a .git path formatting routine with output buffer
  Fix potentially dangerous uses of mkpath and git_path
  Fix potentially dangerous uses of mkpath and git_path
  Fix mkpath abuse in dwim_ref and dwim_log of sha1_name.c
  Add mksnpath which allows you to specify the output buffer

Conflicts:
	builtin-revert.c
2008-11-05 11:35:53 -08:00
Junio C Hamano efcce2e1f0 Merge branch 'mv/maint-branch-m-symref'
* mv/maint-branch-m-symref:
  update-ref --no-deref -d: handle the case when the pointed ref is packed
  git branch -m: forbid renaming of a symref
  Fix git update-ref --no-deref -d.
  rename_ref(): handle the case when the reflog of a ref does not exist
  Fix git branch -m for symrefs.
2008-11-05 11:33:19 -08:00
Nicolas Pitre 09ded04b7e make unpack_object_header() non fatal
It is possible to have pack corruption in the object header.  Currently
unpack_object_header() simply die() on them instead of letting the caller
deal with that gracefully.

So let's have unpack_object_header() return an error instead, and find
a better name for unpack_object_header_gently() in that context.  All
callers of unpack_object_header() are ready for it.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-11-02 15:22:34 -08:00
Nicolas Pitre 0e8189e270 close another possibility for propagating pack corruption
Abstract
--------

With index v2 we have a per object CRC to allow quick and safe reuse of
pack data when repacking.  This, however, doesn't currently prevent a
stealth corruption from being propagated into a new pack when _not_
reusing pack data as demonstrated by the modification to t5302 included
here.

The Context
-----------

The Git database is all checksummed with SHA1 hashes.  Any kind of
corruption can be confirmed by verifying this per object hash against
corresponding data.  However this can be costly to perform systematically
and therefore this check is often not performed at run time when
accessing the object database.

First, the loose object format is entirely compressed with zlib which
already provide a CRC verification of its own when inflating data.  Any
disk corruption would be caught already in this case.

Then, packed objects are also compressed with zlib but only for their
actual payload.  The object headers and delta base references are not
deflated for obvious performance reasons, however this leave them
vulnerable to potentially undetected disk corruptions.  Object types
are often validated against the expected type when they're requested,
and deflated size must always match the size recorded in the object header,
so those cases are pretty much covered as well.

Where corruptions could go unnoticed is in the delta base reference.
Of course, in the OBJ_REF_DELTA case,  the odds for a SHA1 reference to
get corrupted so it actually matches the SHA1 of another object with the
same size (the delta header stores the expected size of the base object
to apply against) are virtually zero.  In the OBJ_OFS_DELTA case, the
reference is a pack offset which would have to match the start boundary
of a different base object but still with the same size, and although this
is relatively much more "probable" than in the OBJ_REF_DELTA case, the
probability is also about zero in absolute terms.  Still, the possibility
exists as demonstrated in t5302 and is certainly greater than a SHA1
collision, especially in the OBJ_OFS_DELTA case which is now the default
when repacking.

Again, repacking by reusing existing pack data is OK since the per object
CRC provided by index v2 guards against any such corruptions. What t5302
failed to test is a full repack in such case.

The Solution
------------

As unlikely as this kind of stealth corruption can be in practice, it
certainly isn't acceptable to propagate it into a freshly created pack.
But, because this is so unlikely, we don't want to pay the run time cost
associated with extra validation checks all the time either.  Furthermore,
consequences of such corruption in anything but repacking should be rather
visible, and even if it could be quite unpleasant, it still has far less
severe consequences than actively creating bad packs.

So the best compromize is to check packed object CRC when unpacking
objects, and only during the compression/writing phase of a repack, and
only when not streaming the result.  The cost of this is minimal (less
than 1% CPU time), and visible only with a full repack.

Someone with a stats background could provide an objective evaluation of
this, but I suspect that it's bad RAM that has more potential for data
corruptions at this point, even in those cases where this extra check
is not performed.  Still, it is best to prevent a known hole for
corruption when recreating object data into a new pack.

What about the streamed pack case?  Well, any client receiving a pack
must always consider that pack as untrusty and perform full validation
anyway, hence no such stealth corruption could be propagated to remote
repositoryes already.  It is therefore worthless doing local validation
in that case.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-11-02 15:22:15 -08:00
Junio C Hamano 86e67a088c Merge branch 'jk/maint-ls-files-other' into maint
* jk/maint-ls-files-other:
  refactor handling of "other" files in ls-files and status
2008-11-02 13:37:13 -08:00