Commit graph

45 commits

Author SHA1 Message Date
brian m. carlson e023ff0691 t: remove test_oid_init in tests
Now that we call test_oid_init in the setup for all test scripts,
there's no point in calling it individually.  Remove all of the places
where we've done so to help keep tests tidy.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-30 09:16:49 -07:00
Derrick Stolee 3ce4ca0a56 multi-pack-index: respect repack.packKeptObjects=false
When selecting a batch of pack-files to repack in the "git
multi-pack-index repack" command, Git should respect the
repack.packKeptObjects config option. When false, this option says that
the pack-files with an associated ".keep" file should not be repacked.
This config value is "false" by default.

There are two cases for selecting a batch of objects. The first is the
case where the input batch-size is zero, which specifies "repack
everything". The second is with a non-zero batch size, which selects
pack-files using a greedy selection criteria. Both of these cases are
updated and tested.

Reported-by: Son Luong Ngoc <sluongng@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-10 09:50:55 -07:00
Junio C Hamano 0ccf0bafff Merge branch 'ds/t5319-touch-fix'
Tests update to use "test-chmtime" instead of "touch -t".

* ds/t5319-touch-fix:
  t5319: replace 'touch -m' with 'test-tool chmtime'
2020-04-28 15:50:02 -07:00
Derrick Stolee e892a56845 t5319: replace 'touch -m' with 'test-tool chmtime'
The use of 'touch -m' to modify a file's mtime is slightly less
portable than using our own 'test-tool chmtime'. The important
thing is that these pack-files are ordered in a special way to
ensure the multi-pack-index selects some as the "newer" pack-files
when resolving duplicate objects.

Reported-by: Jeff King <peff@peff.net>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-01 14:37:50 -07:00
Damien Robert 796d61cdc0 midx.c: fix an integer underflow
When verifying a midx index with 0 objects, the
    m->num_objects - 1
underflows and wraps around to 4294967295.

Fix this both by checking that the midx contains at least one oid,
and also that we don't write any midx when there is no packfiles.

Update the tests to check that `git multi-pack-index write` does
not write an midx when there is no objects, and another to check
that `git multi-pack-index verify` warns when it verifies an midx with no
objects. For this last test, use t5319/no-objects.midx which was
generated by an older version of git.

Signed-off-by: Damien Robert <damien.olivier.robert+git@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-28 16:50:40 -07:00
brian m. carlson 3c5e65cac1 t5319: make test work with SHA-256
This test corrupts various locations in a multi-pack index to test
various error responses.  However, these offsets differ between SHA-1
indexes and SHA-256 indexes due to differences in object length.  Use
test_oid to look up the correct offsets based on the algorithm.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 14:06:19 -08:00
brian m. carlson 235d3cddb8 t5319: change invalid offset for SHA-256 compatibility
When using SHA-1, the existing value of the byte we use is 0x13, so
writing the byte 0x07 serves to corrupt the test and verify that we
detect corruption.  However, when we use SHA-256, the value at that
offset is already 0x07, so our "corruption" doesn't work and the test
fails to detect it.

To provide a value that is truly out of range, let's use 0xff, which is
not likely to be a valid value as the high byte of a two-byte offset in
a multi-pack index this small.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-15 14:06:19 -08:00
William Baker 680cba2c2b multi-pack-index: add [--[no-]progress] option.
Add the --[no-]progress option to git multi-pack-index.
Pass the MIDX_PROGRESS flag to the subcommand functions
when progress should be displayed by multi-pack-index.
The progress feature was added to 'verify' in 144d703
("multi-pack-index: report progress during 'verify'", 2018-09-13)
but some subcommands were not updated to display progress, and
the ability to opt-out was overlooked.

Signed-off-by: William Baker <William.Baker@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-23 12:05:06 +09:00
Derrick Stolee 3612c2334a t5319: use 'test-tool path-utils' instead of 'ls -l'
Using 'ls -l' and parsing the columns to find file sizes is
problematic when the platform could report the owner as a name
with spaces. Instead, use the 'test-tool path-utils file-size'
command to list only the sizes.

Reported-by: Johannes Sixt <j6t@kdbg.org>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-01 13:47:15 -07:00
Derrick Stolee b526d8cbbb t5319-multi-pack-index.sh: test batch size zero
The 'git multi-pack-index repack' command can take a batch size of
zero, which creates a new pack-file containing all objects in the
multi-pack-index. The first 'repack' command will create one new
pack-file, and an 'expire' command after that will delete the old
pack-files, as they no longer contain any referenced objects in the
multi-pack-index.

We must remove the .keep file that was added in the previous test
in order to expire that pack-file.

Also test that a 'repack' will do nothing if there is only one
pack-file.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-11 10:34:41 -07:00
Derrick Stolee 10bfa3f7f5 midx: add test that 'expire' respects .keep files
The 'git multi-pack-index expire' subcommand may delete packs that
are not needed from the perspective of the multi-pack-index. If
a pack has a .keep file, then we should not delete that pack. Add
a test that ensures we preserve a pack that would otherwise be
expired. First, create a new pack that contains every object in
the repo, then add it to the multi-pack-index. Then create a .keep
file for a pack starting with "a-pack" that was added in the
previous test. Finally, expire and verify that the pack remains
and the other packs were expired.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-11 10:34:40 -07:00
Derrick Stolee d2743315d4 multi-pack-index: test expire while adding packs
During development of the multi-pack-index expire subcommand, a
version went out that improperly computed the pack order if a new
pack was introduced while other packs were being removed. Part of
the subtlety of the bug involved the new pack being placed before
other packs that already existed in the multi-pack-index.

Add a test to t5319-multi-pack-index.sh that catches this issue.
The test adds new packs that cause another pack to be expired, and
creates new packs that are lexicographically sorted before and
after the existing packs.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-11 10:34:40 -07:00
Derrick Stolee ce1e4a105b midx: implement midx_repack()
To repack with a non-zero batch-size, first sort all pack-files by
their modified time. Second, walk those pack-files from oldest
to newest, compute their expected size, and add the packs to a list
if they are smaller than the given batch-size. Stop when the total
expected size is at least the batch size.

If the batch size is zero, select all packs in the multi-pack-index.

Finally, collect the objects from the multi-pack-index that are in
the selected packs and send them to 'git pack-objects'. Write a new
multi-pack-index that includes the new pack.

Using a batch size of zero is very similar to a standard 'git repack'
command, except that we do not delete the old packs and instead rely
on the new multi-pack-index to prevent new processes from reading the
old packs. This does not disrupt other Git processes that are currently
reading the old packs based on the old multi-pack-index.

While first designing a 'git multi-pack-index repack' operation, I
started by collecting the batches based on the actual size of the
objects instead of the size of the pack-files. This allows repacking
a large pack-file that has very few referencd objects. However, this
came at a significant cost of parsing pack-files instead of simply
reading the multi-pack-index and getting the file information for
the pack-files. The "expected size" version provides similar
behavior, but could skip a pack-file if the average object size is
much larger than the actual size of the referenced objects, or
can create a large pack if the actual size of the referenced objects
is larger than the expected size.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-11 10:34:40 -07:00
Derrick Stolee 2af890bb28 multi-pack-index: prepare 'repack' subcommand
In an environment where the multi-pack-index is useful, it is due
to many pack-files and an inability to repack the object store
into a single pack-file. However, it is likely that many of these
pack-files are rather small, and could be repacked into a slightly
larger pack-file without too much effort. It may also be important
to ensure the object store is highly available and the repack
operation does not interrupt concurrent git commands.

Introduce a 'repack' subcommand to 'git multi-pack-index' that
takes a '--batch-size' option. The subcommand will inspect the
multi-pack-index for referenced pack-files whose size is smaller
than the batch size, until collecting a list of pack-files whose
sizes sum to larger than the batch size. Then, a new pack-file
will be created containing the objects from those pack-files that
are referenced by the multi-pack-index. The resulting pack is
likely to actually be smaller than the batch size due to
compression and the fact that there may be objects in the pack-
files that have duplicate copies in other pack-files.

The current change introduces the command-line arguments, and we
add a test that ensures we parse these options properly. Since
we specify a small batch size, we will guarantee that future
implementations do not change the list of pack-files.

In addition, we hard-code the modified times of the packs in
the pack directory to ensure the list of packs sorted by modified
time matches the order if sorted by size (ascending). This will
be important in a future test.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-11 10:34:40 -07:00
Derrick Stolee 19575c7c8e multi-pack-index: implement 'expire' subcommand
The 'git multi-pack-index expire' subcommand looks at the existing
mult-pack-index, counts the number of objects referenced in each
pack-file, deletes the pack-fils with no referenced objects, and
rewrites the multi-pack-index to no longer reference those packs.

Refactor the write_midx_file() method to call write_midx_internal()
which now takes an existing 'struct multi_pack_index' and a list
of pack-files to drop (as specified by the names of their pack-
indexes). As we write the new multi-pack-index, we drop those
file names from the list of known pack-files.

The expire_midx_packs() method removes the unreferenced pack-files
after carefully closing the packs to avoid open handles.

Test that a new pack-file that covers the contents of two other
pack-files leads to those pack-files being deleted during the
expire subcommand. Be sure to read the multi-pack-index to ensure
it no longer references those packs.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-11 10:34:40 -07:00
Derrick Stolee cff9711616 multi-pack-index: prepare for 'expire' subcommand
The multi-pack-index tracks objects in a collection of pack-files.
Only one copy of each object is indexed, using the modified time
of the pack-files to determine tie-breakers. It is possible to
have a pack-file with no referenced objects because all objects
have a duplicate in a newer pack-file.

Introduce a new 'expire' subcommand to the multi-pack-index builtin.
This subcommand will delete these unused pack-files and rewrite the
multi-pack-index to no longer refer to those files. More details
about the specifics will follow as the method is implemented.

Add a test that verifies the 'expire' subcommand is correctly wired,
but will still be valid when the verb is implemented. Specifically,
create a set of packs that should all have referenced objects and
should not be removed during an 'expire' operation. The packs are
created carefully to ensure they have a specific order when sorted
by size. This will be important in a later test.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-11 10:34:40 -07:00
Jeff King fc78915674 packfile: fix pack basename computation
When we have a multi-pack-index that covers many packfiles, we try to
avoid opening the .idx for those packfiles. To do that we feed the pack
name to midx_contains_pack(). But that function wants to see only the
basename, which we compute using strrchr() to find the final slash. But
that leaves an extra "/" at the start of our string.

We can fix this by incrementing the pointer. That also raises the
question of what to do when the name does not have a '/' at all. This
should generally not happen (we always find files in "pack/"), but it
doesn't hurt to be defensive here.

Let's wrap all of that up in a helper function and make it publicly
available, since a later patch will need to use it, too.

The tests don't notice because there's nothing about opening those .idx
files that would cause us to give incorrect output. It's just a little
slower. The new test checks this case by corrupting the covered .idx,
and then making sure we don't complain about it.

We also have to tweak t5570, which intentionally corrupts a .idx file
and expects us to notice it. When run with GIT_TEST_MULTI_PACK_INDEX,
this will fail since we now will (correctly) not bother opening the .idx
at all. We can fix that by unconditionally dropping any midx that's
there, which ensures we'll have to read the .idx.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-16 16:58:21 +09:00
Jeff King 5670ad98a8 t5319: drop useless --buffer from cat-file
The cat-file --buffer option is the default already when using
--batch-all-objects. It doesn't hurt to specify it, but it's nice for
the test scripts to model good usage.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-16 16:58:21 +09:00
Jeff King b4a14394af t5319: fix bogus cat-file argument
There's no such argument as "--unsorted"; it's spelled "--unordered".
But our test failed to notice that cat-file didn't run at all because:

  1. It lost the exit code of git on the left-hand side of a pipe.

  2. It was comparing two runs of the broken invocation with and without
     a particular config variable (and indeed, both cases produced no
     output!).

Let's fix the option, but also tweak the helper function to check the
exit code.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-16 16:58:21 +09:00
Junio C Hamano 5fb9263295 Merge branch 'ds/test-multi-pack-index'
Tests for the recently introduced multi-pack index machinery.

* ds/test-multi-pack-index:
  packfile: close multi-pack-index in close_all_packs
  multi-pack-index: define GIT_TEST_MULTI_PACK_INDEX
  midx: close multi-pack-index on repack
  midx: fix broken free() in close_midx()
2018-11-13 22:37:19 +09:00
Derrick Stolee 0465a50506 multi-pack-index: define GIT_TEST_MULTI_PACK_INDEX
The multi-pack-index feature is tested in isolation by
t5319-multi-pack-index.sh, but there are many more interesting
scenarios in the test suite surrounding pack-file data shapes
and interactions. Since the multi-pack-index is an optional
data structure, it does not make sense to include it by default
in those tests.

Instead, add a new GIT_TEST_MULTI_PACK_INDEX environment variable
that enables core.multiPackIndex and writes a multi-pack-index
after each 'git repack' command. This adds extra test coverage
when needed.

There are a few spots in the test suite that need to react to this
change:

* t5319-multi-pack-index.sh: there is a test that checks that
  'git repack' deletes the multi-pack-index. Disable the environment
  variable to ensure this still happens.

* t5310-pack-bitmaps.sh: One test moves a pack-file from the object
  directory to an alternate. This breaks the multi-pack-index, so
  delete the multi-pack-index at this point, if it exists.

* t9300-fast-import.sh: One test verifies the number of files in
  the .git/objects/pack directory is exactly 8. Exclude the
  multi-pack-index from this count so it is still 8 in all cases.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-22 10:42:46 +09:00
Derrick Stolee 66ec0390e7 fsck: verify multi-pack-index
When core.multiPackIndex is true, we may have a multi-pack-index
in our object directory. Add calls to 'git multi-pack-index verify'
at the end of 'git fsck' if so.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 13:49:41 -07:00
Derrick Stolee cc6af73c02 multi-pack-index: verify object offsets
The 'git multi-pack-index verify' command must verify the object
offsets stored in the multi-pack-index are correct. There are two
ways the offset chunk can be incorrect: the pack-int-id and the
object offset.

Replace the BUG() statement with a die() statement, now that we
may hit a bad pack-int-id during a 'verify' command on a corrupt
multi-pack-index, and it is covered by a test.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 13:49:41 -07:00
Derrick Stolee 55c5648d80 multi-pack-index: verify oid lookup order
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 13:49:41 -07:00
Derrick Stolee 2f23d3f3f9 multi-pack-index: verify oid fanout order
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 13:49:41 -07:00
Derrick Stolee d4bf1d88b9 multi-pack-index: verify missing pack
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 13:49:41 -07:00
Derrick Stolee 8e72a3c321 multi-pack-index: verify packname order
The final check we make while loading a multi-pack-index is that
the packfile names are in lexicographical order. Make this error
be a die() instead.

In order to test this condition, we need multiple packfiles.
Earlier in t5319-multi-pack-index.sh, we tested the interaction with
'git repack' but this limits us to one packfile in our object dir.
Move these repack tests until after the 'verify' tests.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 13:49:41 -07:00
Derrick Stolee d3f8e21170 multi-pack-index: verify corrupt chunk lookup table
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 13:49:41 -07:00
Derrick Stolee 53ad040744 multi-pack-index: verify bad header
When verifying if a multi-pack-index file is valid, we want the
command to fail to signal an invalid file. Previously, we wrote
an error to stderr and continued as if we had no multi-pack-index.
Now, die() instead of error().

Add tests that check corrupted headers in a few ways:

* Bad signature
* Bad file version
* Bad hash version
* Truncated hash count
* Extended hash count

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 13:49:41 -07:00
Derrick Stolee 56ee7ff156 multi-pack-index: add 'verify' verb
The multi-pack-index builtin writes multi-pack-index files, and
uses a 'write' verb to do so. Add a 'verify' verb that checks this
file matches the contents of the pack-indexes it replaces.

The current implementation is a no-op, but will be extended in
small increments in later commits.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17 13:49:38 -07:00
Derrick Stolee 6a22d52126 pack-objects: consider packs in multi-pack-index
When running 'git pack-objects --local', we want to avoid packing
objects that are in an alternate. Currently, we check for these
objects using the packed_git_mru list, which excludes the pack-files
covered by a multi-pack-index.

Add a new iteration over the multi-pack-indexes to find these
copies and mark them as unwanted.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 15:31:40 -07:00
Derrick Stolee e9ab2ed7de midx: test a few commands that use get_all_packs
The new get_all_packs() method exposed the packfiles coverede by
a multi-pack-index. Before, the 'git cat-file --batch' and
'git count-objects' commands would skip objects in an environment
with a multi-pack-index.

Further, a reachability bitmap would be ignored if its pack-file
was covered by a multi-pack-index.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 15:31:40 -07:00
Derrick Stolee 29e2016b8f midx: fix bug that skips midx with alternates
The logic for constructing the linked list of multi-pack-indexes
in the object store is incorrect. If the local object store has
a multi-pack-index, but an alternate does not, then the list is
dropped.

Add tests that would have revealed this bug.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 15:31:39 -07:00
Derrick Stolee 525e18c04b midx: clear midx on repack
If a 'git repack' command replaces existing packfiles, then we must
clear the existing multi-pack-index before moving the packfiles it
references.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:29 -07:00
Derrick Stolee c4d25228eb config: create core.multiPackIndex setting
The core.multiPackIndex config setting controls the multi-pack-
index (MIDX) feature. If false, the setting will disable all reads
from the multi-pack-index file.

Read this config setting in the new prepare_multi_pack_index_one()
which is called during prepare_packed_git(). This check is run once
per repository.

Add comparison commands in t5319-multi-pack-index.sh to check
typical Git behavior remains the same as the config setting is turned
on and off. This currently includes 'git rev-list' and 'git log'
commands to trigger several object database reads. Currently, these
would only catch an error in the prepare_multi_pack_index_one(), but
with later commits will catch errors in object lookups, abbreviations,
and approximate object counts.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee 662148c435 midx: write object offsets
The final pair of chunks for the multi-pack-index file stores the object
offsets. We default to using 32-bit offsets as in the pack-index version
1 format, but if there exists an offset larger than 32-bits, we use a
trick similar to the pack-index version 2 format by storing all offsets
at least 2^31 in a 64-bit table; we use the 32-bit table to point into
that 64-bit table as necessary.

We only store these 64-bit offsets if necessary, so create a test that
manipulates a version 2 pack-index to fake a large offset. This allows
us to test that the large offset table is created, but the data does not
match the actual packfile offsets. The multi-pack-index offset does match
the (corrupted) pack-index offset, so a future feature will compare these
offsets during a 'verify' step.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee d7cacf29cc midx: write object id fanout chunk
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee 0d5b3a5ef7 midx: write object ids in a chunk
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee 3227565cfd midx: read pack names into array
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee 32f3c541e3 multi-pack-index: write pack names in chunk
The multi-pack-index needs to track which packfiles it indexes. Store
these in our first required chunk. Since filenames are not well
structured, add padding to keep good alignment in later chunks.

Modify the 'git multi-pack-index read' subcommand to output the
existence of the pack-file name chunk. Modify t5319-multi-pack-index.sh
to reflect this new output and the new expected number of chunks.

Defense in depth: A pattern we are using in the multi-pack-index feature
is to verify the data as we write it. We want to ensure we never write
invalid data to the multi-pack-index. There are many checks that verify
that the values we are writing fit the format definitions. This mainly
helps developers while working on the feature, but it can also identify
issues that only appear when dealing with very large data sets. These
large sets are hard to encode into test cases.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee 396f257018 multi-pack-index: read packfile list
When constructing a multi-pack-index file for a given object directory,
read the files within the enclosed pack directory and find matches that
end with ".idx" and find the correct paired packfile using
add_packed_git().

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee 2c3813354b t5319: expand test data
As we build the multi-pack-index file format, we want to test the format
on real repositories. Add tests that create repository data including
multiple packfiles with both version 1 and version 2 formats.

The current 'git multi-pack-index write' command will always write the
same file with no "real" data. This will be expanded in future commits,
along with the test expectations.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee 4d80560c54 multi-pack-index: load into memory
Create a new multi_pack_index struct for loading multi-pack-indexes into
memory. Create a test-tool builtin for reading basic information about
that multi-pack-index to verify the correct data is written.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee fc59e74844 midx: write header information to lockfile
As we begin writing the multi-pack-index format to disk, start with
the basics: the 12-byte header and the 20-byte checksum footer. Start
with these basics so we can add the rest of the format in small
increments.

As we implement the format, we will use a technique to check that our
computed offsets within the multi-pack-index file match what we are
actually writing. Each method that writes to the hashfile will return
the number of bytes written, and we will track that those values match
our expectations.

Currently, write_midx_header() returns 12, but is not checked. We will
check the return value in a later commit.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00
Derrick Stolee a340773026 multi-pack-index: add 'write' verb
In anticipation of writing multi-pack-indexes, add a skeleton
'git multi-pack-index write' subcommand and send the options to a
write_midx_file() method. Also create a skeleton test script that
tests the 'write' subcommand.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-20 11:27:28 -07:00