The building of the reflog message is using strbuf, which is not
friendly with internationalization frameworks. No other reflog
messages are translated right now and switching all the messages to
i18n would require a major rework of the way the messages are built.
Signed-off-by: Jean-Noel Avila <jn.avila@free.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we init a submodule, we try to die when it has no URL
defined:
url = xstrdup(sub->url);
if (!url)
die(...);
But that's clearly nonsense. xstrdup() will never return
NULL, and if sub->url is NULL, we'll segfault.
These two bits of code need to be flipped, so we check
sub->url before looking at it.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The only caller of this function passes in a static buffer
returned from git_path(). This looks dangerous at first
glance, but turns out to be OK because the first thing we do
is xstrdup() the result.
Let's turn this into a git_pathdup(). That's slightly more
efficient (no extra copy), and makes it easier to audit for
dangerous git_path() invocations.
Since there's only a single caller, let's just set this
default path inside the init function. That makes the memory
ownership clear.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Writing directly into the strbuf avoids a useless copy of
the data, and dropping calls to git_path() makes it easier
to audit for dangerous calls.
Note that git_path() does an implicit strbuf_reset(), but in
each of these cases we were either already doing that reset,
or writing into a fresh strbuf anyway.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It's more efficient to use git_pathdup(), as it skips an
extra copy of the path. And by removing some calls to
git_path(), it makes it easier to audit for dangerous uses.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Long ago we added functions like git_path_merge_msg() to
replace the more dangerous git_path("MERGE_MSG"). Over time
some new calls to the latter have crept it. Let's convert
them to use the safer form.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rather than have a variable with a short name that is fed to
git_path(), let's add a helper function that returns the
full path. This avoids the dangerous git_path() function.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As explained in the document. This option has an advantage over the
command sequence "git worktree add && git worktree lock": there will be
no gap that somebody can accidentally "prune" the new worktree (or soon,
explicitly "worktree remove" it).
"worktree add" does keep a lock on while it's preparing the worktree.
If --lock is specified, this lock remains after the worktree is created.
Suggested-by: David Taylor <David.Taylor@dell.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If the full hostname doesn't fit in the buffer supplied to
gethostname, POSIX does not specify whether the buffer will be
null-terminated, so to be safe, we should do it ourselves. Introduce
new function, xgethostname, which ensures that there is always a \0
at the end of the buffer.
Signed-off-by: David Turner <dturner@twosigma.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
POSIX limits the length of host names to HOST_NAME_MAX. Export the
fallback definition from daemon.c and use this constant to make all
buffers used with gethostname(2) big enough for any possible result
and a terminating NUL.
Inspired-by: David Turner <dturner@twosigma.com>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: David Turner <dturner@twosigma.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Don't assume that the current working directory is the root of the
repository. Correctly generate the path for the recursing child
processes by building it from the work_tree() root instead. Otherwise if
we run ls-files using --git-dir or --work-tree it will not work
correctly as it attempts to change directory into a potentially invalid
location. Best case, it doesn't exist and we produce an error. Worst
case we cd into the wrong location and unknown behavior occurs.
Add a new test which highlights this possibility.
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Recent update to for_each_replace_name() to make it use a strbuf in
place of a fixed buffer forgot to release the memory held by the
strbuf before leaving the function.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
So far we can only pass one flag, respect_includes, to thie function. We
need to pass some more (non-flag even), so let's make it accept a struct
instead of an integer.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since commit e77aa336f1 ("ls-files: optionally recurse into
submodules", 2016-10-07) ls-files has known how to recurse into
submodules when displaying files.
Unfortunately this fails for certain cases, including when nesting more
than one submodule, called from within a submodule that itself has
submodules, or when the GIT_DIR environemnt variable is set.
Prior to commit b58a68c1c1 ("setup: allow for prefix to be passed to
git commands", 2017-03-17) this resulted in an error indicating that
--prefix and --super-prefix were incompatible.
After this commit, instead, the process loops forever with a GIT_DIR set
to the parent and continuously reads the parent submodule files and
recursing forever.
Fix this by preparing the environment properly for submodules when
setting up the child process. This is similar to how other commands such
as grep behave.
This was not caught by the original tests because the scenario is
avoided if the submodules are created separately and not stored as the
standard method of putting the submodule git directory under
.git/modules/<name>. We can update the test to show the failure by the
addition of "git submodule absorbgitdirs" to the test case. However,
note that this new test would run forever without the necessary fix in
this patch.
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Avoid closing stdin, but do close an actual input file on error exit.
Found with Cppcheck.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are no more direct calls to am_signoff(), so we can fold its
logic in am_append_signoff().
(This is done in a separate commit rather than in the previous one, to
make it easier to revert this specific change if additional calls are
ever introduced.)
Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signoff is handled in parse_mail(), but not in parse_mail_rebasing(),
since the latter is only used when git-rebase calls git-am with the
--rebasing option, and --signoff is never passed in this case.
In order to introduce (in the upcoming commits) support for
`git-rebase --signoff`, we must make git-am pay attention to it also
in the rebase case. This can be done by moving the conditional
addition of the signoff from parse_mail() to the caller am_run(),
after either of the parse_mail*() functions were called.
Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since 722ff7f87 (receive-pack: quarantine objects until
pre-receive accepts, 2016-10-03), we have to feed the
pre-receive hook the tmp_objdir environment, so that git
programs run from the hook know where to find the objects.
That commit modified run_update_hook() to do the same, but
there it is a noop. By the time we get to the update hooks,
we have already migrated the objects from quarantine, and so
tmp_objdir_env() will always return NULL. We can drop this
useless call.
Note that the ordering here and the lack of support for the
update hook is intentional. The update hook calls are
interspersed with actual ref updates, and we must migrate
the objects before any refs are updated (since otherwise
those refs would appear broken to outside processes). So the
only other options are:
- remain in quarantine for the _first_ ref, but not the
others. This is sufficiently confusing that it can be
rejected outright.
- run all the individual update hooks first, then migrate,
then update all the refs. But this changes the repository
state that the update hooks see (i.e., whether or not
refs from the same push are updated yet or not).
So the functionality is fine and remains unchanged with this
patch; we're just cleaning up a useless and confusing line
of code.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the cleanup phase for the grep command to free the pathspec
struct that's allocated earlier in the same block, and used just a few
lines earlier.
With "grep hi README.md" valgrind reports a loss of 239 bytes now,
down from 351.
The relevant --num-callers=40 --leak-check=full --show-leak-kinds=all
backtrace is:
[...] 187 (112 direct, 75 indirect) bytes in 1 blocks are definitely lost in loss record 70 of 110
[...] at 0x4C2BBAF: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
[...] by 0x60B339: do_xmalloc (wrapper.c:59)
[...] by 0x60B2F6: xmalloc (wrapper.c:86)
[...] by 0x576B37: parse_pathspec (pathspec.c:652)
[...] by 0x4519F0: cmd_grep (grep.c:1215)
[...] by 0x4062EF: run_builtin (git.c:371)
[...] by 0x40544D: handle_builtin (git.c:572)
[...] by 0x4060A2: run_argv (git.c:624)
[...] by 0x4051C6: cmd_main (git.c:701)
[...] by 0x4C5901: main (common-main.c:43)
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach git to skip verification of the SHA1-1 checksum at the end of
the index file in verify_hdr() which is called from read_index()
unless the "force_verify_index_checksum" global variable is set.
Teach fsck to force this verification.
The checksum verification is for detecting disk corruption, and for
small projects, the time it takes to compute SHA-1 is not that
significant, but for gigantic repositories this calculation adds
significant time to every command.
These effect can be seen using t/perf/p0002-read-cache.sh:
Test HEAD~1 HEAD
--------------------------------------------------------------------------------------
0002.1: read_cache/discard_cache 1000 times 0.66(0.44+0.20) 0.30(0.27+0.02) -54.5%
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the next patch we need the ability to expand '~' to
real_path($HOME). But we can't do that from outside because '~' is part
of a pattern, not a true path. Add an option to expand_user_path() to do
so.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It only has one caller, not worth keeping just for convenience.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The left and right base directories were pointed to the buf field of
two strbufs, which were subject to change.
A contrived test case shows the problem where a file with a long enough
name to force the strbuf to grow is up-to-date (hence the code path is
used where the work tree's version of the file is reused), and then a
file that is not up-to-date needs to be written (hence the code path is
used where checkout_entry() uses the previously recorded base_dir that
is invalid by now).
Let's just copy the base_dir strings for use with checkout_entry(),
never touch them until the end, and release them then. This is an easily
verifiable fix (as opposed to the next-obvious alternative: to re-set
base_dir after every loop iteration).
This fixes https://github.com/git-for-windows/git/issues/1124
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add the 'push-check' subcommand to submodule--helper which is used to
check if the provided remote and refspec can be used as part of a push
operation in the submodule.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There isn't any obvious reason for the 'struct string_list push_options'
and 'struct string_list_item *item' to be marked as static, so unmark
them as being static. Also, clear the push_options string_list to
prevent memory leaking.
Signed-off-by: Brandon Williams <bmwill@google.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we notice that we have a local copy of an incoming
object, we compare the two objects to make sure we haven't
found a collision. Before we get to the actual object
bytes, though, we compare the type and size from
sha1_object_info().
If our local object is corrupted, then the type will be
OBJ_BAD, which obviously will not match the incoming type,
and we'll report "SHA1 COLLISION FOUND" (with capital
letters and everything). This is confusing, as the problem
is not a collision but rather local corruption. We should
report that instead (just like we do if reading the rest of
the object content fails a few lines later).
Note that we _could_ just ignore the error and mark it as a
non-collision. That would let you "git fetch" to replace a
corrupted object. But it's not a very reliable method for
repairing a repository. The earlier want/have negotiation
tries to get the other side to omit objects we already have,
and it would not realize that we are "missing" this
corrupted object. So we're better off complaining loudly
when we see corruption, and letting the user take more
drastic measures to repair (like making a full clone
elsewhere and copying the pack into place).
Note that the test sets transfer.unpackLimit in the
receiving repository so that we use index-pack (which is
what does the collision check). Normally for such a small
push we'd use unpack-objects, which would simply try to
write the loose object, and discard the new one when we see
that there's already an old one.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since this structure handles an array of object IDs, rename it to struct
oid_array. Also rename the accessor functions and the initialization
constant.
This commit was produced mechanically by providing non-Documentation
files to the following Perl one-liners:
perl -pi -E 's/struct sha1_array/struct oid_array/g'
perl -pi -E 's/\bsha1_array_/oid_array_/g'
perl -pi -E 's/SHA1_ARRAY_INIT/OID_ARRAY_INIT/g'
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make sha1_array_for_each_unique take a callback using struct object_id.
Since one of these callbacks is an argument to for_each_abbrev, convert
those as well. Rename various functions, replacing "sha1" with "oid".
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert this function by changing the declaration and definition and
applying the following semantic patch to update the callers:
@@
expression E1, E2;
@@
- sha1_array_lookup(E1, E2.hash)
+ sha1_array_lookup(E1, &E2)
@@
expression E1, E2;
@@
- sha1_array_lookup(E1, E2->hash)
+ sha1_array_lookup(E1, E2)
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are a very small number of callers which don't already use struct
object_id. Convert them.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the callers to pass struct object_id by changing the function
declaration and definition and applying the following semantic patch:
@@
expression E1, E2;
@@
- sha1_array_append(E1, E2.hash)
+ sha1_array_append(E1, &E2)
@@
expression E1, E2;
@@
- sha1_array_append(E1, E2->hash)
+ sha1_array_append(E1, E2)
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We probe the "17/" loose object directory for auto-gc, and
use a local buffer to format the path. We can just use
git_path() for this. It handles paths of any length
(reducing our error handling). And because we feed the
result straight to a system call, we can just use the static
variant.
Note that git_path also knows the string "objects/" is
special, and will replace it with git_object_directory()
when necessary.
Another alternative would be to use sha1_file_name() for the
pretend object "170000...", but that ends up being more
hassle for no gain, as we have to truncate the final path
component.
Signed-off-by: Jeff King <peff@peff.net>
We'd prefer to avoid unchecked snprintf calls because
truncation can lead to unexpected results.
These are all cases where truncation shouldn't ever happen,
because the input to snprintf is fixed in size. That makes
them candidates for xsnprintf(), but it's simpler still to
just use the heap, and then nobody has to wonder if "100" is
big enough.
We'll use xstrfmt() where possible, and a strbuf when we need
the resulting size or to reuse the same buffer in a loop.
Signed-off-by: Jeff King <peff@peff.net>
After receive-pack reads the pack header from the client, it
feeds the already-read part to index-pack and unpack-objects
via their --pack-header command-line options. To do so, we
format it into a fixed buffer, then duplicate it into the
child's argv_array.
Our buffer is long enough to handle any possible input, so
this isn't wrong. But it's more complicated than it needs to
be; we can just argv_array_pushf() the final value and avoid
the intermediate copy. This drops the magic number and is
more efficient, too.
Note that we need to push to the argv_array in order, which
means we can't do the push until we are in the "unpack-objects
versus index-pack" conditional. Rather than duplicate the
slightly complicated format specifier, I pushed it into a
helper function.
Signed-off-by: Jeff King <peff@peff.net>
When name-rev needs to format an actual name, we do so into
a fixed-size buffer. That includes the actual ref tip, as
well as any traversal information. Since refs can exceed
1024 bytes, this means you can get a bogus result. E.g.,
doing:
git tag $(perl -e 'print join("/", 1..1024)')
git describe --contains HEAD^
results in ".../282/283", when it should be
".../1023/1024~1".
We can solve this by using a heap buffer. We'll use a
strbuf, which lets us write into the same buffer from our
loop without having to reallocate.
Signed-off-by: Jeff King <peff@peff.net>
Many functions which handle refs use a PATH_MAX-sized buffer
to do so. This is mostly reasonable as we have to write
loose refs into the filesystem, and at least on Linux the 4K
PATH_MAX is big enough that nobody would care. But:
1. The static PATH_MAX is not always the filesystem limit.
2. On other platforms, PATH_MAX may be much smaller.
3. As we move to alternate ref storage, we won't be bound
by filesystem limits.
Let's convert these to heap buffers so we don't have to
worry about truncation or size limits.
We may want to eventually constrain ref lengths for sanity
and to prevent malicious names, but we should do so
consistently across all platforms, and in a central place
(like the ref code).
Signed-off-by: Jeff King <peff@peff.net>
Part of the reflog content comes from the environment, which
can be much larger than our fixed buffer. Let's use a heap
buffer so we avoid truncating it.
Signed-off-by: Jeff King <peff@peff.net>
We format the tag header into a fixed 1024-byte buffer. But
since the tag-name and tagger ident can be arbitrarily
large, we may unceremoniously die with "tag header too big".
Let's just use a strbuf instead.
Note that it looks at first glance like we can just format
this directly into the "buf" strbuf where it will ultimately
go. But that buffer may already contain the tag message, and
we have no easy way to prepend formatted data to a strbuf
(we can only splice in an already-generated buffer). This
isn't a performance-critical path, so going through an extra
buffer isn't a big deal.
Signed-off-by: Jeff King <peff@peff.net>
In order to checkout files, difftool reads "diff --raw"
output and feeds the names to checkout_entry(). That
function requires us to have a "struct cache_entry". And
because that struct uses a FLEX_ARRAY for the name field, we
have to actually copy in our new name.
The current code allocates a single re-usable cache_entry
that can hold a name up to PATH_MAX, and then copies
filenames into it using strcpy(). But there's no guarantee
that incoming names are smaller than PATH_MAX. They've come
from "diff --raw" output which might be diffing between two
trees (and hence we'd be subject to the PATH_MAX of some
other system, or even none at all if they were created
directly via "update-index").
We can fix this by using make_cache_entry() to create a
correctly-sized cache_entry for each name. This incurs an
extra allocation per file, but this is negligible compared
to actually writing out the file contents.
To make this simpler, we can push this procedure into a new
helper function. Note that we can also get rid of the "len"
variables for src_path and dst_path (and in fact we must, as
the compiler complains that they are unused).
Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As xgetcwd() returns an allocated buffer, we should free this
buffer when we don't need it any more.
This was found by Coverity.
Reported-by: Jeff King <peff@peff.net>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The odb_mkstemp() function expects the caller to provide a
fixed buffer to write the resulting tempfile name into. But
it creates the template using snprintf without checking the
return value. This means we could silently truncate the
filename.
In practice, it's unlikely that the truncation would end in
the template-pattern that mkstemp needs to open the file. So
we'd probably end up failing either way, unless the path was
specially crafted.
The simplest fix would be to notice the truncation and die.
However, we can observe that most callers immediately
xstrdup() the result anyway. So instead, let's switch to
using a strbuf, which is easier for them (and isn't a big
deal for the other 2 callers, who can just strbuf_release
when they're done with it).
Note that many of the callers used static buffers, but this
was purely to avoid putting a large buffer on the stack. We
never passed the static buffers out of the function, so
there's no complicated memory handling we need to change.
Signed-off-by: Jeff King <peff@peff.net>
The odb_mkstemp function does not return an error; it dies
on failure instead. But many of its callers compare the
resulting descriptor against -1 and die themselves.
Mostly this is just pointless, but it does raise a question
when looking at the callers: if they show the results of the
"template" buffer after a failure, what's in it? The answer
is: it doesn't matter, because it cannot happen.
So let's make that clear by removing the bogus error checks.
In bitmap_writer_finish(), we can drop the error-handling
code entirely. In the other two cases, it's shared with the
open() in another code path; we can just move the
error-check next to that open() call.
And while we're at it, let's flesh out the function's
docstring a bit to make the error behavior clear.
Signed-off-by: Jeff King <peff@peff.net>
Make the internal storage for struct sha1_array use an array of struct
object_id internally. Update the users of this struct which inspect its
internals.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert virtually all uses of unsigned char [20] to struct object_id.
Leave all the arguments that come from struct sha1_array, as these will
be converted in a later patch.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All of the callers of this function have been converted, so convert this
function and update the callers. This function also calls
sha1_array_append, which we'll convert shortly.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert some hardcoded constants into uses of parse_oid_hex.
Additionally, convert all uses of struct command, and miscellaneous
other functions necessary for that. This work is necessary to be able
to convert sha1_array_append later on.
To avoid needing to specify a constant, reject shallow lines with the
wrong length instead of simply ignoring them.
Note that in queue_command we are guaranteed to have a NUL-terminated
buffer or at least one byte of overflow that we can safely read, so the
linelen check can be elided. We would die in such a case, but not read
invalid memory.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If we had already processed the last newline in a push certificate, we
would end up subtracting NULL from the end-of-certificate pointer when
computing the length of the line. This would have resulted in an
absurdly large length, and possibly a buffer overflow. Instead,
subtract the beginning-of-certificate pointer from the
end-of-certificate pointer, which is what's expected.
Note that this situation should never occur, since not only do we
require the certificate to be newline terminated, but the signature will
only be read from the beginning of a line. Nevertheless, it seems
prudent to correct it.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git describe --debug localizes all debug messages but not the terms
head, lightweight, annotated that it outputs for the candidates.
Localize them, too.
Signed-off-by: Michael J Gruber <git@grubix.eu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the caller of sha1_array_append to struct object_id.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>