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52735 commits

Author SHA1 Message Date
Junio C Hamano ae4e3f4ae2 Merge branch 'sb/trailers-docfix'
Doc update.

* sb/trailers-docfix:
  Documentation/git-interpret-trailers: explain possible values
2018-08-15 15:08:19 -07:00
Junio C Hamano 5a6693089f Merge branch 'jk/ui-color-always-to-auto'
Doc formatting fix.

* jk/ui-color-always-to-auto:
  Documentation: fix --color option formatting
2018-08-15 15:08:19 -07:00
Elijah Newren 1076f1e454 Remove forward declaration of an enum
According to http://c-faq.com/null/machexamp.html, sizeof(char*) !=
sizeof(int*) on some platforms.  Since an enum could be a char or int
(or long or...), knowing the size of the enum thus is important to
knowing the size of a pointer to an enum, so we cannot just forward
declare an enum the way we can a struct.  (Also, modern C++ compilers
apparently define forward declarations of an enum to either be useless
because the enum was defined, or require an explicit size specifier, or
be a compilation error.)

Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-15 11:52:09 -07:00
Elijah Newren f790d81252 compat/precompose_utf8.h: use more common include guard style
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-15 11:52:09 -07:00
Elijah Newren 64e68a3b32 urlmatch.h: fix include guard
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-15 11:52:09 -07:00
Elijah Newren e730b81df6 Move definition of enum branch_track from cache.h to branch.h
'branch_track' feels more closely related to branching, and it is
needed later in branch.h; rather than #include'ing cache.h in branch.h
for this small enum, just move the enum and the external declaration
for git_branch_track to branch.h.

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-15 11:52:09 -07:00
Elijah Newren 1731310745 alloc: make allocate_alloc_state and clear_alloc_state more consistent
Since both functions are using the same data type, they should either both
refer to it as void *, or both use the real type (struct alloc_state *).
Opt for the latter.

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-15 11:52:09 -07:00
Elijah Newren ef3ca95475 Add missing includes and forward declarations
I looped over the toplevel header files, creating a temporary two-line C
program for each consisting of
  #include "git-compat-util.h"
  #include $HEADER
This patch is the result of manually fixing errors in compiling those
tiny programs.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-15 11:52:09 -07:00
Phillip Wood dd2e36ebac rebase -i: fix numbering in squash message
Commit e12a7ef597 ("rebase -i: Handle "combination of <n> commits" with
GETTEXT_POISON", 2018-04-27) changed the way that individual commit
messages are labelled when squashing commits together. In doing so a
regression was introduced where the numbering of the messages is off by
one. This commit fixes that and adds a test for the numbering.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-15 10:50:24 -07:00
Johannes Schindelin 1ce2b452c6 chainlint: fix for core.autocrlf=true
The `chainlint` target compares actual output to expected output, where
the actual output is generated from files that are specifically checked
out with LF-only line endings. So the expected output needs to be
checked out with LF-only line endings, too.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-15 10:40:46 -07:00
Jonathan Nieder 5641eb9465 partial-clone: render design doc using asciidoc
Rendered documentation can be easier to read than raw text because
headings and emphasized phrases stand out.  Add the missing markup and
Makefile rule required to render this design document using asciidoc.

Tested by running

  make -C Documentation technical/partial-clone.html

and viewing the output in a browser.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-15 09:22:54 -07:00
Ævar Arnfjörð Bjarmason 2711b1ad5e submodule: add more exhaustive up-path testing
The tests added in 63e95beb08 ("submodule: port resolve_relative_url
from shell to C", 2016-04-15) didn't do a good job of testing various
up-path invocations where the up-path would bring us beyond even the
URL in question without emitting an error.

These results look nonsensical, but it's worth exhaustively testing
them before fixing any of this code, so we can see which of these
cases were changed.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-14 12:55:17 -07:00
Stefan Beller e84c3cf3dc git-submodule.sh: accept verbose flag in cmd_update to be non-quiet
In a56771a668 (builtin/pull: respect verbosity settings in submodules,
2018-01-25), we made sure to pass on both quiet and verbose flag from
builtin/pull.c to the submodule shell script. However git-submodule doesn't
understand a verbose flag, which results in a bug when invoking

  git pull --recurse-submodules -v [...]

There are a few different approaches to fix this bug:

1) rewrite 'argv_push_verbosity' or its caller in builtin/pull.c to
   cap opt_verbosity at 0. Then 'argv_push_verbosity' would only add
   '-q' if any.

2) Have a flag in 'argv_push_verbosity' that specifies if we allow adding
  -q or -v (or both).

3) Add -v to git-submodule.sh and make it a no-op

(1) seems like a maintenance burden: What if we add code after
the submodule operations or move submodule operations higher up,
then we have altered the opt_verbosity setting further down the line
in builtin/pull.c.

(2) seems like it could work reasonably well without more regressions

(3) seems easiest to implement as well as actually is a feature with the
    last-one-wins rule of passing flags to Git commands.

Reported-by: Jochen Kühner
Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-14 12:48:28 -07:00
Jeff King 0889aae1cd for_each_*_object: move declarations to object-store.h
The for_each_loose_object() and for_each_packed_object()
functions are meant to be part of a unified interface: they
use the same set of for_each_object_flags, and it's not
inconceivable that we might one day add a single
for_each_object() wrapper around them.

Let's put them together in a single file, so we can avoid
awkwardness like saying "the flags for this function are
over in cache.h". Moving the loose functions to packfile.h
is silly. Moving the packed functions to cache.h works, but
makes the "cache.h is a kitchen sink" problem worse. The
best place is the recently-created object-store.h, since
these are quite obviously related to object storage.

The for_each_*_in_objdir() functions do not use the same
flags, but they are logically part of the same interface as
for_each_loose_object(), and share callback signatures. So
we'll move those, as well, as they also make sense in
object-store.h.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-14 12:29:57 -07:00
Jeff King 79ed0a5e26 cat-file: use a single strbuf for all output
When we're in batch mode, we end up in batch_object_write()
for each object, which allocates its own strbuf for each
call. Instead, we can provide a single "scratch" buffer that
gets reused for each output. When running:

  git cat-file --batch-all-objects --batch-check='%(objectname)'

on git.git, my best-of-five time drops from:

  real	0m0.171s
  user	0m0.159s
  sys	0m0.012s

to:

  real	0m0.133s
  user	0m0.121s
  sys	0m0.012s

Note that we could do this just by putting the "scratch"
pointer into "struct expand_data", but I chose instead to
add an extra parameter to the callstack. That's more
verbose, but it makes it a bit more obvious what is going
on, which in turn makes it easy to see where we need to be
releasing the string in the caller (right after the loop
which uses it in each case).

Based-on-a-patch-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-14 12:29:54 -07:00
Jeff King 54d2f0d945 cat-file: split batch "buf" into two variables
We use the "buf" strbuf for two things: to read incoming
lines, and as a scratch space for test-expanding the
user-provided format. Let's split this into two variables
with descriptive names, which makes their purpose and
lifetime more clear.

It will also help in a future patch when we start using the
"output" buffer for more expansions.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-14 12:29:00 -07:00
Jeff King ced9fff75d cat-file: use oidset check-and-insert
We don't need to check if the oidset has our object before
we insert it; that's done as part of the insertion. We can
just rely on the return value from oidset_insert(), which
saves one hash lookup per object.

This measurable speedup is tiny and within the run-to-run
noise, but the result is simpler to read, too.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-14 12:27:53 -07:00
SZEDER Gábor 10c600172c t5310-pack-bitmaps: fix bogus 'pack-objects to file can use bitmap' test
The test 'pack-objects to file can use bitmap' added in 645c432d61
(pack-objects: use reachability bitmap index when generating
non-stdout pack, 2016-09-10) is silently buggy and doesn't check what
it's supposed to.

In 't5310-pack-bitmaps.sh', the 'list_packed_objects' helper function
does what its name implies by running:

  git show-index <"$1" | cut -d' ' -f2

The test in question invokes this function like this:

  list_packed_objects <packa-$packasha1.idx >packa.objects &&
  list_packed_objects <packb-$packbsha1.idx >packb.objects &&
  test_cmp packa.objects packb.objects

Note how these two callsites don't specify the name of the pack index
file as the function's parameter, but redirect the function's standard
input from it.  This triggers an error message from the shell, as it
has no filename to redirect from in the function, but this error is
ignored, because it happens upstream of a pipe.  Consequently, both
invocations produce empty 'pack{a,b}.objects' files, and the
subsequent 'test_cmp' happily finds those two empty files identical.

Fix these two 'list_packed_objects' invocations by specifying the pack
index files as parameters.  Furthermore, eliminate the pipe in that
function by replacing it with an &&-chained pair of commands using an
intermediate file, so a failure of 'git show-index' or the shell
redirection will fail the test.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-14 08:55:30 -07:00
Johannes Sixt d641097589 mingw: enable atomic O_APPEND
The Windows CRT implements O_APPEND "manually": on write() calls, the
file pointer is set to EOF before the data is written. Clearly, this is
not atomic. And in fact, this is the root cause of failures observed in
t5552-skipping-fetch-negotiator.sh and t5503-tagfollow.sh, where
different processes write to the same trace file simultanously; it also
occurred in t5400-send-pack.sh, but there it was worked around in
71406ed4d6 ("t5400: avoid concurrent writes into a trace file",
2017-05-18).

Fortunately, Windows does support atomic O_APPEND semantics using the
file access mode FILE_APPEND_DATA. Provide an implementation that does.

This implementation is minimal in such a way that it only implements
the open modes that are actually used in the Git code base. Emulation
for other modes can be added as necessary later. To become aware of
the necessity early, the unusal error ENOSYS is reported if an
unsupported mode is encountered.

Diagnosed-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Helped-by: Jeff Hostetler <git@jeffhostetler.com>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 15:22:19 -07:00
Nguyễn Thái Ngọc Duy ecbbc0a53b blame.c: remove implicit dependency on the_index
Side note, since we gain access to the right repository, we can stop
rely on the_repository in this code as well.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:44 -07:00
Nguyễn Thái Ngọc Duy 1b5c6c1e53 apply.c: remove implicit dependency on the_index
Use apply_state->repo->index instead of the_index (in most cases,
unless we need to use a temporary index in some functions). Let the
callers (am and apply) tell us what to use, instead of always assuming
to operate on the_index.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:44 -07:00
Nguyễn Thái Ngọc Duy 82ea77eca7 apply.c: make init_apply_state() take a struct repository
We're moving away from the_index in this code. "struct index_state *"
could be added to struct apply_state. But let's aim long term and put
struct repository here instead so that we could even avoid more global
states in the future. The index will be available via
apply_state->repo->index.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:44 -07:00
Nguyễn Thái Ngọc Duy 332a82a522 apply.c: pass struct apply_state to more functions
we're going to remove the dependency on the_index by moving 'struct
index_state *' to somewhere inside struct apply_state. Let's make sure
relevant functions have access to this struct now and reduce the diff
noise when the actual conversion happens.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:44 -07:00
Nguyễn Thái Ngọc Duy ff82d1260f resolve-undo.c: use the right index instead of the_index
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:44 -07:00
Nguyễn Thái Ngọc Duy b67b55127c archive-*.c: use the right repository
With 'struct archive_args' gaining new repository pointer, we don't
have to assume the_repository in the archive backends anymore.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:44 -07:00
Nguyễn Thái Ngọc Duy b612ee202a archive.c: avoid access to the_index
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy a4009b0b45 grep: use the right index instead of the_index
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy c4500e251f attr: remove index from git_attr_set_direction()
Since attr checking API now take the index, there's no need to set an
index in advance with this call. Most call sites are straightforward
because they either pass the_index or NULL (which defaults back to
the_index previously). There's only one suspicious call site in
unpack-trees.c where it sets a different index.

This code in unpack-trees is about to check out entries from the
new/temporary index after merging is done in it. The attributes will
be used by entry.c code to do crlf conversion if needed. entry.c now
respects struct checkout's istate field, and this field is correctly
set in unpack-trees.c, there should be no regression from this change.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy 74cfc0ee1d entry.c: use the right index instead of the_index
checkout-index.c needs update because if checkout->istate is NULL,
ie_match_stat() will crash. Previously this is ie_match_stat(&the_index, ..)
so it will not crash, but it is not technically correct either.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy 68f08b4b23 submodule.c: use the right index instead of the_index
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy d17ef3a94e pathspec.c: use the right index instead of the_index
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy c7f3259d0d unpack-trees: avoid the_index in verify_absent()
Both functions that are updated in this commit are called by
verify_absent(), which is part of the "unpack-trees" operation that is
supposed to work on any index file specified by the caller. Thanks to
Brandon [1] [2], an implicit dependency on the_index is exposed. This
commit fixes it.

In both functions, it makes sense to use src_index to check for
exclusion because it's almost unchanged and should give us the same
outcome as if running the exclude check before the unpack.

It's "almost unchanged" because we do invalidate cache-tree and
untracked cache in the source index. But this should not affect how
exclude machinery uses the index: to see if a file is tracked, and to
read a blob from the index instead of worktree if it's marked
skip-worktree (i.e. it's not available in worktree)

[1] a0bba65b10 (dir: convert is_excluded to take an index - 2017-05-05
[2] 2c1eb10454 (dir: convert read_directory to take an index - 2017-05-05)

Helped-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy 27c82fb3b4 unpack-trees: convert clear_ce_flags* to avoid the_index
Prior to fba92be8f7, this code implicitly (and incorrectly) assumes
the_index when running the exclude machinery. fba92be8f7 helps show
this problem clearer because unpack-trees operation is supposed to
work on whatever index the caller specifies... not specifically
the_index.

Update the code to use "istate" argument that's originally from
mark_new_skip_worktree(). From the call sites, both in unpack_trees(),
you can see that this function works on two separate indexes:
o->src_index and o->result. The second mark_new_skip_worktree() so far
has incorecctly applied exclude rules on o->src_index instead of
o->result. It's unclear what is the consequences of this, but it's
definitely wrong.

[1] fba92be8f7 (dir: convert is_excluded_from_list to take an index -
    2017-05-05)

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy 86016ec304 unpack-trees: don't shadow global var the_index
This function mark_new_skip_worktree() has an argument named the_index
which is also the name of a global variable. While they have different
types (the global the_index is not a pointer) mistakes can easily
happen and it's also confusing for readers. Rename the function
argument to something other than the_index.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy 383480ba4f unpack-trees: add a note about path invalidation
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy 340f4bc9f8 unpack-trees: remove 'extern' on function declaration
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy a52b321d2e ls-files: correct index argument to get_convert_attr_ascii()
write_eolinfo() does take an istate as function argument and it should
be used instead of the_index.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:43 -07:00
Nguyễn Thái Ngọc Duy f9beff0336 preload-index.c: use the right index instead of the_index
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:42 -07:00
Nguyễn Thái Ngọc Duy 6d2df284e7 dir.c: remove an implicit dependency on the_index in pathspec code
Make the match_patchspec API and friends take an index_state instead
of assuming the_index in dir.c. All external call sites are converted
blindly to keep the patch simple and retain current behavior.
Individual call sites may receive further updates to use the right
index instead of the_index.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:42 -07:00
Nguyễn Thái Ngọc Duy 7f944e264e convert.c: remove an implicit dependency on the_index
Make the convert API take an index_state instead of assuming the_index
in convert.c. All external call sites are converted blindly to keep
the patch simple and retain current behavior. Individual call sites
may receive further updates to use the right index instead of
the_index.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:42 -07:00
Nguyễn Thái Ngọc Duy 7a400a2c02 attr: remove an implicit dependency on the_index
Make the attr API take an index_state instead of assuming the_index in
attr code. All call sites are converted blindly to keep the patch
simple and retain current behavior. Individual call sites may receive
further updates to use the right index instead of the_index.

There is one ugly temporary workaround added in attr.c that needs some
more explanation.

Commit c24f3abace (apply: file commited with CRLF should roundtrip
diff and apply - 2017-08-19) forces one convert_to_git() call to NOT
read the index at all. But what do you know, we read it anyway by
falling back to the_index. When "istate" from convert_to_git is now
propagated down to read_attr_from_array() we will hit segfault
somewhere inside read_blob_data_from_index.

The right way of dealing with this is to kill "use_index" variable and
only follow "istate" but at this stage we are not ready for that:
while most git_attr_set_direction() calls just passes the_index to be
assigned to use_index, unpack-trees passes a different one which is
used by entry.c code, which has no way to know what index to use if we
delete use_index. So this has to be done later.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:42 -07:00
Nguyễn Thái Ngọc Duy 07096c9696 cache-tree: wrap the_index based wrappers with #ifdef
This puts update_main_cache_tree() and write_cache_as_tree() in the
same group of "index compat" functions that assume the_index
implicitly, which should only be used within builtin/ or t/helper.

sequencer.c is also updated to not use these functions. As of now, no
files outside builtin/ use these functions anymore.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:42 -07:00
Nguyễn Thái Ngọc Duy ff7fe37b05 diff.c: move read_index() code back to the caller
This code is only needed for diff-tree (since f0c6b2a2fd ([PATCH]
Optimize diff-tree -[CM] --stdin - 2005-05-27)). Let the caller do the
preparation instead and avoid read_index() in diff.c code.

read_index() should be avoided (in addition to the_index) because it
uses get_index_file() underneath to get the path $GIT_DIR/index. This
effectively pulls the_repository in and may become the only reason to
pull a 'struct repository *' in diff.c. Let's keep the dependencies as
few as possible and kick it back to diff-tree.c

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 14:14:42 -07:00
Jeff King 0750bb5b51 cat-file: support "unordered" output for --batch-all-objects
If you're going to access the contents of every object in a
packfile, it's generally much more efficient to do so in
pack order, rather than in hash order. That increases the
locality of access within the packfile, which in turn is
friendlier to the delta base cache, since the packfile puts
related deltas next to each other. By contrast, hash order
is effectively random, since the sha1 has no discernible
relationship to the content.

This patch introduces an "--unordered" option to cat-file
which iterates over packs in pack-order under the hood. You
can see the results when dumping all of the file content:

  $ time ./git cat-file --batch-all-objects --buffer --batch | wc -c
  6883195596

  real	0m44.491s
  user	0m42.902s
  sys	0m5.230s

  $ time ./git cat-file --unordered \
                        --batch-all-objects --buffer --batch | wc -c
  6883195596

  real	0m6.075s
  user	0m4.774s
  sys	0m3.548s

Same output, different order, way faster. The same speed-up
applies even if you end up accessing the object content in a
different process, like:

  git cat-file --batch-all-objects --buffer --batch-check |
  grep blob |
  git cat-file --batch='%(objectname) %(rest)' |
  wc -c

Adding "--unordered" to the first command drops the runtime
in git.git from 24s to 3.5s.

  Side note: there are actually further speedups available
  for doing it all in-process now. Since we are outputting
  the object content during the actual pack iteration, we
  know where to find the object and could skip the extra
  lookup done by oid_object_info(). This patch stops short
  of that optimization since the underlying API isn't ready
  for us to make those sorts of direct requests.

So if --unordered is so much better, why not make it the
default? Two reasons:

  1. We've promised in the documentation that --batch-all-objects
     outputs in hash order. Since cat-file is plumbing,
     people may be relying on that default, and we can't
     change it.

  2. It's actually _slower_ for some cases. We have to
     compute the pack revindex to walk in pack order. And
     our de-duplication step uses an oidset, rather than a
     sort-and-dedup, which can end up being more expensive.
     If we're just accessing the type and size of each
     object, for example, like:

       git cat-file --batch-all-objects --buffer --batch-check

     my best-of-five warm cache timings go from 900ms to
     1100ms using --unordered. Though it's possible in a
     cold-cache or under memory pressure that we could do
     better, since we'd have better locality within the
     packfile.

And one final question: why is it "--unordered" and not
"--pack-order"? The answer is again two-fold:

  1. "pack order" isn't a well-defined thing across the
     whole set of objects. We're hitting loose objects, as
     well as objects in multiple packs, and the only
     ordering we're promising is _within_ a single pack. The
     rest is apparently random.

  2. The point here is optimization. So we don't want to
     promise any particular ordering, but only to say that
     we will choose an ordering which is likely to be
     efficient for accessing the object content. That leaves
     the door open for further changes in the future without
     having to add another compatibility option.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 13:48:31 -07:00
Jeff King b1adb38458 cat-file: rename batch_{loose,packed}_object callbacks
We're not really doing the batch-show operation in these
callbacks, but just collecting the set of objects. That
distinction will become more important in a future patch, so
let's rename them now to avoid cluttering that diff.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 13:48:30 -07:00
Jeff King aa2f5ef500 t1006: test cat-file --batch-all-objects with duplicates
The test for --batch-all-objects in t1006 covers a variety
of object storage situations, but one thing it doesn't cover
is that we avoid mentioning duplicate objects. We won't have
any because running "git repack -ad" will have packed them
all and deleted the loose ones.

This does work (because we sort and de-dup the output list),
but it's good to include it in our test. And doubly so for
when we add an unordered mode which has to de-dup in a
different way.

Note that we cannot just re-create one of the objects, as
Git will omit the write of an object that is already
present. However, we can create a new pack with one of the
objects, which forces the duplication.

One alternative would be to just use "git repack -a" instead
of "-ad". But then _every_ object would be duplicated as
loose and packed, and we might miss a bug that omits packed
objects (because we'd show their loose counterparts).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 13:48:29 -07:00
Jeff King 736eb88fdc for_each_packed_object: support iterating in pack-order
We currently iterate over objects within a pack in .idx
order, which uses the object hashes. That means that it
is effectively random with respect to the location of the
object within the pack. If you're going to access the actual
object data, there are two reasons to move linearly through
the pack itself:

  1. It improves the locality of access in the packfile. In
     the cold-cache case, this may mean fewer disk seeks, or
     better usage of disk cache.

  2. We store related deltas together in the packfile. Which
     means that the delta base cache can operate much more
     efficiently if we visit all of those related deltas in
     sequence, as the earlier items are likely to still be
     in the cache.  Whereas if we visit the objects in
     random order, our cache entries are much more likely to
     have been evicted by unrelated deltas in the meantime.

So in general, if you're going to access the object contents
pack order is generally going to end up more efficient.

But if you're simply generating a list of object names, or
if you're going to end up sorting the result anyway, you're
better off just using the .idx order, as finding the pack
order means generating the in-memory pack-revindex.
According to the numbers in 8b8dfd5132 (pack-revindex:
radix-sort the revindex, 2013-07-11), that takes about 200ms
for linux.git, and 20ms for git.git (those numbers are a few
years old but are still a good ballpark).

That makes it a good optimization for some cases (we can
save tens of seconds in git.git by having good locality of
delta access, for a 20ms cost), but a bad one for others
(e.g., right now "cat-file --batch-all-objects
--batch-check="%(objectname)" is 170ms in git.git, so adding
20ms to that is noticeable).

Hence this patch makes it an optional flag. You can't
actually do any interesting timings yet, as it's not plumbed
through to any user-facing tools like cat-file. That will
come in a later patch.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 13:48:28 -07:00
Jeff King 8b36155190 for_each_*_object: give more comprehensive docstrings
We already mention the local/alternate behavior of these
functions, but we can help clarify a few other behaviors:

 - there's no need to mention LOCAL_ONLY specifically, since
   we already reference the flags by type (and as we add
   more flags, we don't want to have to mention each)

 - clarify that reachability doesn't matter here; this is
   all accessible objects

 - what ordering/uniqueness guarantees we give

 - how pack-specific flags are handled for the loose case

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 13:48:26 -07:00
Jeff King a7ff6f5a0f for_each_*_object: take flag arguments as enum
It's not wrong to pass our flags in an "unsigned", as we
know it will be at least as large as the enum.  However,
using the enum in the declaration makes it more obvious
where to find the list of flags.

While we're here, let's also drop the "extern" noise-words
from the declarations, per our modern coding style.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 13:48:25 -07:00
Jeff King 202e7f1e16 for_each_*_object: store flag definitions in a single location
These flags were split between cache.h and packfile.h,
because some of the flags apply only to packs. However, they
share a single numeric namespace, since both are respected
for the packed variant. Let's make sure they're defined
together so that nobody accidentally adds a new flag in one
location that duplicates the other.

While we're here, let's also put them in an enum (which
helps debugger visibility) and use "(1<<n)" rather than
counting powers of 2 manually.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-13 13:47:50 -07:00