tests: fix and add lint for non-portable grep --file

The --file option to grep isn't in POSIX[1], but -f is[1]. Let's check
for that in the future, and fix the portability regression in
f237c8b6fe ("commit-graph: implement git-commit-graph write",
2018-04-02) that broke e.g. AIX.

1. http://pubs.opengroup.org/onlinepubs/009695399/utilities/grep.html

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tests: fix version-specific portability issue in Perl JSON

The test guarded by PERLJSON added in 75459410ed ("json_writer: new
routines to create JSON data", 2018-07-13) assumed that a JSON boolean
value like "true" or "false" would be represented as "1" or "0" in
Perl.

This behavior can't be relied upon, e.g. with JSON.pm 2.50 and
JSON::PP. A JSON::PP::Boolean object will be represented as "true"
or "false". To work around this let's check if we have any refs left
after we check for hashes and arrays, assume those are JSON objects,
and coerce them to a known boolean value.

The behavior of this test still looks odd to me. Why implement our own
ad-hoc encoder just for some one-off test, as opposed to say Perl's
own Data::Dumper with Sortkeys et al? But with this change it works,
so let's leave it be.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tests: use shorter labels in chainlint.sed for AIX sed

Improve the portability of chainlint by using shorter labels. On
AIX sed will complain about:

sed: 0602-417 The label :hereslurp is greater than eight
characters

This, in combination with the previous fix to this file makes
GIT_TEST_CHAIN_LINT=1 (which is the default) working again on AIX
without issues, and the "gmake check-chainlint" test also passes.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

range-diff: update stale summary of --no-dual-color

275267937b (range-diff: make dual-color the default mode, 2018-08-13)
replaced --dual-color with --no-dual-color but left the option's
summary untouched. Rewrite the summary to describe --no-dual-color
rather than dual-color.

Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Kyle Meyer <kyle@kyleam.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Document update for nd/unpack-trees-with-cache-tree

Fix an incorrect comment in the new code added in b4da37380b
(unpack-trees: optimize walking same trees with cache-tree -
2018-08-18) and document about the new test variable that is enabled
by default in test-lib.sh in 4592e6080f (cache-tree: verify valid
cache-tree in the test suite - 2018-08-18)

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tests: fix comment syntax in chainlint.sed for AIX sed

Change a comment in chainlint.sed to appease AIX sed, which would
previously print this error:

sed: # stash for later printing is not a recognized function

1. https://public-inbox.org/git/CAPig+cTTbU5HFMKgNyrxTp3+kcK46-Fn=4ZH6zDt1oQChAc3KA@mail.gmail.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tests: fix and add lint for non-portable seq

The seq command is not in POSIX, and doesn't exist on
e.g. OpenBSD. We've had the test_seq wrapper since d17cf5f3a3 ("tests:
Introduce test_seq", 2012-08-04), but use of it keeps coming back,
e.g. in the recently added "fetch negotiator" tests being added here.

So let's also add a check to "make test-lint". The regex is aiming to
capture the likes of $(seq ..) and "seq" as a stand-alone command,
without capturing some existing cases where we e.g. have files called
"seq", as \bseq\b would do.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tests: fix and add lint for non-portable head -c N

The "head -c BYTES" option is non-portable (not in POSIX[1]). Change
such invocations to use the test_copy_bytes wrapper added in
48860819e8 ("t9300: factor out portable "head -c" replacement",
2016-06-30).

This fixes a test added in 9d2e330b17 ("ewah_read_mmap: bounds-check
mmap reads", 2018-06-14), which has been breaking
t5310-pack-bitmaps.sh on OpenBSD since 2.18.0. The OpenBSD ports
already have a similar workaround after their upgrade to 2.18.0[2].

I have not tested this on IRIX, but according to 4de0bbd898 ("t9300:
use perl "head -c" clone in place of "dd bs=1 count=16000" kluge",
2010-12-13) this invocation would have broken things there too.

Also, change a valgrind-specific codepath in test-lib.sh to use this
wrapper. Given where valgrind runs I don't think this would ever
become a portability issue in practice, but it's easier to just use
the wrapper than introduce some exception for the "make test-lint"
check being added here.

1. http://pubs.opengroup.org/onlinepubs/9699919799/utilities/head.html
2. https://github.com/openbsd/ports/commit/08d5d82eaefe5cf2f125ecc0c6a57df9cf91350c#diff-f7d3c4fabeed1691620d608f1534f5e5

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: fix mistakes in translated strings

Fix typos and convert a question which does not expect to be replied
to a simple advice.

Signed-off-by: Jean-Noël Avila <jn.avila@free.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config: fix commit-graph related config docs

The core.commitGraph config setting was accidentally removed from
the config documentation. In that same patch, the config setting
that writes a commit-graph during garbage collection was incorrectly
written to the doc as "gc.commitGraph" instead of "gc.writeCommitGraph".

Reported-by: Szeder Gábor <szeder.dev@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

append_signoff: use size_t for string offsets

The append_signoff() function takes an "int" to specify the
number of bytes to ignore. Most callers just pass 0, and the
remainder use ignore_non_trailer() to skip over cruft.
That function also returns an int, and uses them internally.

On systems where size_t is larger than an int (i.e., most
64-bit systems), dealing with a ridiculously large commit
message could end up overflowing an int, producing
surprising results (e.g., returning a negative offset, which
would cause us to look outside the original string).

Let's consistently use size_t for these offsets through this
whole stack. As a bonus, this makes the meaning of
"ignore_footer" as an offset (and not a boolean) more clear.
But while we're here, let's also document the interface.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer: ignore "---" divider when parsing trailers

When the sequencer code appends a signoff or cherry-pick
origin, it uses the default trailer-parsing options, which
treat "---" as the end of the commit message. As a result,
it may be fooled by a commit message that contains that
string and fail to find the existing trailer block. Even
more confusing, the actual append code does not know about
"---", and always appends to the end of the string. This can
lead to bizarre results. E.g., appending a signoff to a
commit message like this:

subject

body
---
these dashes confuse the parser!

Signed-off-by: A
results in output with a final block like:

Signed-off-by: A
Signed-off-by: A
The parser thinks the final line of the message is "body",
and ignores everything else, claiming there are no trailers.
So we output an extra newline separator (wrong) and add a
duplicate signoff (also wrong).

Since we know we are feeding a pure commit message, we can
simply tell the parser to ignore the "---" divider.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pretty, ref-filter: format %(trailers) with no_divider option

In both of these cases we know that we are feeding the
trailer-parsing code a pure commit message. We should tell
it so, which avoids false positives for a commit message
that contains a "---" line.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

interpret-trailers: allow suppressing "---" divider

Even with the newly-tightened "---" parser, it's still
possible for a commit message to trigger a false positive if
it contains something like "--- foo". If the caller knows
that it has only a single commit message, it can now tell us
with the "--no-divider" option, eliminating any false
positives.

If we were designing this from scratch, I'd probably make
this the default. But we've advertised the "---" behavior in
the documentation since interpret-trailers has existed.
Since it's meant to be scripted, breaking that would be a
bad idea.

Note that the logic is in the underlying trailer.c code,
which is used elsewhere. The default there will keep the
current behavior, but many callers will benefit from setting
this new option. That's left for future patches.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

interpret-trailers: tighten check for "---" patch boundary

The interpret-trailers command accepts not only raw commit
messages, but it also can manipulate trailers in
format-patch output. That means it must find the "---"
boundary separating the commit message from the patch.
However, it does so by looking for any line starting with
"---", regardless of whether there is further content.

This is overly lax compared to the parsing done in
mailinfo.c's patchbreak(), and may cause false positives
(e.g., t/perf output tables uses dashes; if you cut and
paste them into your commit message, it fools the parser).

We could try to reuse patchbreak() here, but it actually has
several heuristics that are not of interest to us (e.g.,
matching "diff -" without a three-dash separator or even a
CVS "Index:" line). We're not interested in taking in
whatever random cruft people may send, but rather handling
git-formatted patches.

Note that the existing documentation was written in a loose
way, so technically we are changing the behavior from what
it said. But this should implement the original intent in a
more accurate way.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

trailer: pass process_trailer_opts to trailer_info_get()

Most of the trailer code has an "opts" struct which is
filled in by the caller. We don't pass it down to
trailer_info_get(), which does the initial parsing, because
there hasn't yet been a need to do so.

Let's start passing it down in preparation for adding new
options. Note that there's a single caller which doesn't
otherwise have such an options struct. Since it's just one
caller (that we'd have to modify anyway), let's not bother
with any special treatment like accepting a NULL options
struct, and just have it allocate one with the defaults.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

trailer: use size_t for iterating trailer list

We store the length of the trailers list in a size_t. So on
a 64-bit system with a 32-bit int, in the unlikely case that
we manage to actually allocate a list with 2^31 entries,
we'd loop forever trying to iterate over it (our "int" would
wrap to negative before exceeding info->trailer_nr).

This probably doesn't matter in practice. Each entry is at
least a pointer plus a non-empty string, so even without
malloc overhead or the memory to hold the original string
we're parsing from, you'd need to allocate tens of
gigabytes. But it's easy enough to do it right.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

trailer: use size_t for string offsets

Many of the string-parsing functions inside trailer.c return
integer offsets into the string (e.g., to point to the end
of the trailer block). Several of these use an "int" to
return or store the offsets. On a system where "size_t" is
much larger than "int" (e.g., most 64-bit ones), it's easy
to feed a gigantic commit message that results in a negative
offset. This can result in us reading memory before the
string (if the int is used as an index) or far after (if
it's implicitly cast to a size_t by passing to a strbuf
function).

Let's fix this by using size_t for all string offsets. Note
that several of the functions need ssize_t, since they use
"-1" as a sentinel value. The interactions here can be
pretty subtle. E.g., end_of_title in find_trailer_start()
does not itself need to be signed, but it is compared to the
result of last_line(), which is. That promotes the latter to
unsigned, and the ">=" does not behave as you might expect.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/lib-rebase.sh: support explicit 'pick' commands in 'fake_editor.sh'

The verbose output of the test 'reword without issues functions as
intended' in 't3423-rebase-reword.sh', added in a9279c6785 (sequencer:
do not squash 'reword' commits when we hit conflicts, 2018-06-19),
contains the following error output:

sed: -e expression #1, char 2: extra characters after command

This error comes from within the 'fake-editor.sh' script created by
'lib-rebase.sh's set_fake_editor() function, and the root cause is the
FAKE_LINES="pick 1 reword 2" variable in the test in question, in
particular the "pick" word. 'fake-editor.sh' assumes 'pick' to be the
default rebase command and doesn't support an explicit 'pick' command
in FAKE_LINES. As a result, 'pick' will be used instead of a line
number when assembling the following 'sed' script:

sed -n picks/^pick/pick/p

which triggers the aforementioned error.

Luckily, this didn't affect the test's correctness: the erroring 'sed'
command doesn't write anything to the todo script, and processing the
rest of FAKE_LINES generates the desired todo script, as if that
'pick' command were not there at all.

The minimal fix would be to remove the 'pick' word from FAKE_LINES,
but that would leave us susceptible to similar issues in the future.

Instead, teach the fake-editor script to recognize an explicit 'pick'
command, which is still a fairly trivial change.

In the future we might want to consider reinforcing this fake editor
script with an &&-chain and stricter parsing of the FAKE_LINES
variable (e.g. to error out when encountering unknown rebase commands
or commands and line numbers in the wrong order).

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

hashcmp: assert constant hash size

Prior to 509f6f62a4 (cache: update object ID functions for
the_hash_algo, 2018-07-16), hashcmp() called memcmp() with a
constant size of 20 bytes. Some compilers were able to turn
that into a few quad-word comparisons, which is faster than
actually calling memcmp().

In 509f6f62a4, we started using the_hash_algo->rawsz
instead. Even though this will always be 20, the compiler
doesn't know that while inlining hashcmp() and ends up just
generating a call to memcmp().

Eventually we'll have to deal with multiple hash sizes, but
for the upcoming v2.19, we can restore some of the original
performance by asserting on the size. That gives the
compiler enough information to know that the memcmp will
always be called with a length of 20, and it performs the
same optimization.

Here are numbers for p0001.2 run against linux.git on a few
versions. This is using -O2 with gcc 8.2.0.

Test v2.18.0 v2.19.0-rc0 HEAD
------------------------------------------------------------------------------
0001.2: 34.24(33.81+0.43) 34.83(34.42+0.40) +1.7% 33.90(33.47+0.42) -1.0%

You can see that v2.19 is a little slower than v2.18. This
commit ended up slightly faster than v2.18, but there's a
fair bit of run-to-run noise (the generated code in the two
cases is basically the same). This patch does seem to be
consistently 1-2% faster than v2.19.

I tried changing hashcpy(), which was also touched by
509f6f62a4, in the same way, but couldn't measure any
speedup. Which makes sense, at least for this workload. A
traversal of the whole commit graph requires looking up
every entry of every tree via lookup_object(). That's many
multiples of the numbers of objects in the repository (most
of the lookups just return "yes, we already saw that
object").

[jn: verified using "make object.s" that the memcmp call goes away.]

Reported-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Jeff King <peff@peff.net
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

rev-list: make empty --stdin not an error

When we originally did the series that contains 7ba826290a
(revision: add rev_input_given flag, 2017-08-02) the intent
was that "git rev-list --stdin </dev/null" would similarly
become a successful noop. However, an attempt at the time to
do that did not work[1]. The problem is that rev_input_given
serves two roles:

- it tells rev-list.c that it should not error out

- it tells revision.c that it should not have the "default"
ref kick (e.g., "HEAD" in "git log")

We want to trigger the former, but not the latter. This is
technically possible with a single flag, if we set the flag
only after revision.c's revs->def check. But this introduces
a rather subtle ordering dependency.

Instead, let's keep two flags: one to denote when we got
actual input (which triggers both roles) and one for when we
read stdin (which triggers only the first).

This does mean a caller interested in the first role has to
check both flags, but there's only one such caller. And any
future callers might want to make the distinction anyway
(e.g., if they care less about erroring out, and more about
whether revision.c soaked up our stdin).

In fact, we already keep such a flag internally in
revision.c for this purpose, so this is really just exposing
that to the caller (and the old function-local flag can go
away in favor of our new one).

[1] https://public-inbox.org/git/20170802223416.gwiezhbuxbdmbjzx@sigill.intra.peff.net/

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t3420-rebase-autostash: don't try to grep non-existing files

Several tests in 't3420-rebase-autostash.sh' start various rebase
processes that are expected to fail because of merge conflicts. These
tests then run '! grep' to ensure that the autostash feature did its
job, and the dirty contents of a file is gone. However, due to the
test repo's history and the choice of upstream branch that file
shouldn't exist in the conflicted state at all. Consequently, this
'grep' doesn't fail as expected, because it can't find the dirty
content, but it fails because it can't open the file.

Tighten this check by using 'test_path_is_missing' instead, thereby
avoiding unexpected errors from 'grep' as well.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t3903-stash: don't try to grep non-existing file

The test 'store updates stash ref and reflog' in 't3903-stash.sh'
creates a stash from a new file, runs 'git reset --hard' to throw away
any modifications to the work tree, and then runs '! grep' to ensure
that the staged contents are gone. Since the file didn't exist
before, it shouldn't exist after 'git reset' either. Consequently,
this 'grep' doesn't fail as expected, because it can't find the staged
content, but it fails because it can't open the file.

Tighten this check by using 'test_path_is_missing' instead, thereby
avoiding an unexpected error from 'grep' as well.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Merge branch 'nd/pack-deltify-regression-fix'

In a recent update in 2.18 era, "git pack-objects" started
producing a larger than necessary packfiles by missing
opportunities to use large deltas.

* nd/pack-deltify-regression-fix:
pack-objects: fix performance issues on packing large deltas

t6018-rev-list-glob: fix 'empty stdin' test

Prior to d3c6751b18 (tests: make use of the test_must_be_empty
function, 2018-07-27), in the test 'rev-list should succeed with empty
output on empty stdin' in 't6018-rev-list-glob' the empty 'expect'
file served dual purpose: besides specifying the expected output, as
usual, it also served as empty input for 'git rev-list --stdin'.

Then d3c6751b18 came along, and, as part of the conversion to
'test_must_be_empty', removed this empty 'expect' file, not realizing
its secondary purpose. Redirecting stdin from the now non-existing
file failed the test, but since this test expects failure in the first
place, this issue went unnoticed.

Redirect 'git rev-list's stdin explicitly from /dev/null to provide
empty input. (Strictly speaking we don't need this redirection,
because the test script's stdin is already redirected from /dev/null
anyway, but I think it's better to be explicit about it.)

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t4051-diff-function-context: read the right file

The test ' context does not include preceding empty lines' in the
block of tests 'change with long common tail and no context' in
't4051-diff-function-context.sh' tries to read the file
'long_common_tail.diff.diff', but that file doesn't exist as its name
contains one more '.diff' suffixes than necessary.

Despite this error the test still succeeded without checking what it's
supposed to, because this erroneous read is done on the line:

test "$(first_context_line <long_common_tail.diff.diff)" != " "

which means that:

- the command substitution hides the error, so it won't fail the
test, and

- the result of the command substitution is the empty string, which
is, of course, not equal to a single space character, so the
condition is fulfilled, and the test succeeds.

As a minimal fix, fix the name of the file to be read.

In the future we might want to reorganize this test script (1) to use
'test_cmp' instead of 'test's and command substitutions to catch
failing commands and to provide helpful error messages, and (2) to
specify what the expected result actually _is_ instead of what it
isn't.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t0020-crlf: check the right file

In the test 'checkout with autocrlf=input' in 't0020-crlf.sh', one of
the 'has_cr' checks looks at the non-existing file 'two' instead of
'dir/two'. The test still succeeds, without actually checking what it
was supposed to, because this check is expected to fail anyway.

As a minimal fix, fix the name of the file to be checked.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t7501-commit: drop silly command substitution

The test '--dry-run with conflicts fixed from a merge' in
't7501-commit.sh', added in 8dc874b2ee (wt-status.c: set commitable
bit if there is a meaningful merge., 2016-02-15), runs the following
unnecessary and downright bogus command substitution:

! $(git merge --no-commit commit-1) &&

I.e. after 'git merge ...' is executed and expectedly fails, the test
attempts to execute its output:

Merging:
80f2ea2 commit 2
virtual commit-1
found 1 common ancestor:
e60d113 Initial commit
Auto-merging test-file
CONFLICT (content): Merge conflict in test-file
Automatic merge failed; fix conflicts and then commit the result.

as a command, which most likely fails, because there is no such
command as "Merging:". Then '!' negates the failed exit status, the
test continues, and eventually succeeds.

Remove this command substitution and use 'test_must_fail' to ensure
that 'git merge' fails.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

commit: use timestamp_t for author_date_slab

The author_date_slab is used to store the author date of a commit
when walking with the --author-date flag in rev-list or log. This
was added as an 'unsigned long' in

81c6b38b "log: --author-date-order"

Since 'unsigned long' is ambiguous in its bit-ness across platforms
(64-bit in Linux, 32-bit in Windows, for example), most references
to the author dates in commit.c were converted to timestamp_t in

dddbad72 "timestamp_t: a new data type for timestamps"

However, the slab definition was missed, leading to a mismatch in
the data types in Windows. This would not reveal itself as a bug
unless someone authors a commit after February 2106, but commits
can store anything as their author date.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pack-objects: reuse on-disk deltas for thin "have" objects

When we serve a fetch, we pass the "wants" and "haves" from
the fetch negotiation to pack-objects. That tells us not
only which objects we need to send, but we also use the
boundary commits as "preferred bases": their trees and blobs
are candidates for delta bases, both for reusing on-disk
deltas and for finding new ones.

However, this misses some opportunities. Modulo some special
cases like shallow or partial clones, we know that every
object reachable from the "haves" could be a preferred base.
We don't use all of them for two reasons:

1. It's expensive to traverse the whole history and
enumerate all of the objects the other side has.

2. The delta search is expensive, so we want to keep the
number of candidate bases sane. The boundary commits
are the most likely to work.

When we have reachability bitmaps, though, reason 1 no
longer applies. We can efficiently compute the set of
reachable objects on the other side (and in fact already did
so as part of the bitmap set-difference to get the list of
interesting objects). And using this set conveniently
covers the shallow and partial cases, since we have to
disable the use of bitmaps for those anyway.

The second reason argues against using these bases in the
search for new deltas. But there's one case where we can use
this information for free: when we have an existing on-disk
delta that we're considering reusing, we can do so if we
know the other side has the base object. This in fact saves
time during the delta search, because it's one less delta we
have to compute.

And that's exactly what this patch does: when we're
considering whether to reuse an on-disk delta, if bitmaps
tell us the other side has the object (and we're making a
thin-pack), then we reuse it.

Here are the results on p5311 using linux.git, which
simulates a client fetching after `N` days since their last
fetch:

Test origin HEAD
--------------------------------------------------------------------------
5311.3: server (1 days) 0.27(0.27+0.04) 0.12(0.09+0.03) -55.6%
5311.4: size (1 days) 0.9M 237.0K -73.7%
5311.5: client (1 days) 0.04(0.05+0.00) 0.10(0.10+0.00) +150.0%
5311.7: server (2 days) 0.34(0.42+0.04) 0.13(0.10+0.03) -61.8%
5311.8: size (2 days) 1.5M 347.7K -76.5%
5311.9: client (2 days) 0.07(0.08+0.00) 0.16(0.15+0.01) +128.6%
5311.11: server (4 days) 0.56(0.77+0.08) 0.13(0.10+0.02) -76.8%
5311.12: size (4 days) 2.8M 566.6K -79.8%
5311.13: client (4 days) 0.13(0.15+0.00) 0.34(0.31+0.02) +161.5%
5311.15: server (8 days) 0.97(1.39+0.11) 0.30(0.25+0.05) -69.1%
5311.16: size (8 days) 4.3M 1.0M -76.0%
5311.17: client (8 days) 0.20(0.22+0.01) 0.53(0.52+0.01) +165.0%
5311.19: server (16 days) 1.52(2.51+0.12) 0.30(0.26+0.03) -80.3%
5311.20: size (16 days) 8.0M 2.0M -74.5%
5311.21: client (16 days) 0.40(0.47+0.03) 1.01(0.98+0.04) +152.5%
5311.23: server (32 days) 2.40(4.44+0.20) 0.31(0.26+0.04) -87.1%
5311.24: size (32 days) 14.1M 4.1M -70.9%
5311.25: client (32 days) 0.70(0.90+0.03) 1.81(1.75+0.06) +158.6%
5311.27: server (64 days) 11.76(26.57+0.29) 0.55(0.50+0.08) -95.3%
5311.28: size (64 days) 89.4M 47.4M -47.0%
5311.29: client (64 days) 5.71(9.31+0.27) 15.20(15.20+0.32) +166.2%
5311.31: server (128 days) 16.15(36.87+0.40) 0.91(0.82+0.14) -94.4%
5311.32: size (128 days) 134.8M 100.4M -25.5%
5311.33: client (128 days) 9.42(16.86+0.49) 25.34(25.80+0.46) +169.0%

In all cases we save CPU time on the server (sometimes
significant) and the resulting pack is smaller. We do spend
more CPU time on the client side, because it has to
reconstruct more deltas. But that's the right tradeoff to
make, since clients tend to outnumber servers. It just means
the thin pack mechanism is doing its job.

From the user's perspective, the end-to-end time of the
operation will generally be faster. E.g., in the 128-day
case, we saved 15s on the server at a cost of 16s on the
client. Since the resulting pack is 34MB smaller, this is a
net win if the network speed is less than 270Mbit/s. And
that's actually the worst case. The 64-day case saves just
over 11s at a cost of just under 11s. So it's a slight win
at any network speed, and the 40MB saved is pure bonus. That
trend continues for the smaller fetches.

The implementation itself is mostly straightforward, with
the new logic going into check_object(). But there are two
tricky bits.

The first is that check_object() needs access to the
relevant information (the thin flag and bitmap result). We
can do this by pushing these into program-lifetime globals.

The second is that the rest of the code assumes that any
reused delta will point to another "struct object_entry" as
its base. But of course the case we are interested in here
is the one where don't have such an entry!

I looked at a number of options that didn't quite work:

- we could use a flag to signal a reused delta, but it's
not a single bit. We have to actually store the oid of
the base, which is normally done by pointing to the
existing object_entry. And we'd have to modify all the
code which looks at deltas.

- we could add the reused bases to the end of the existing
object_entry array. While this does create some extra
work as later stages consider the extra entries, it's
actually not too bad (we're not sending them, so they
don't cost much in the delta search, and at most we'd
have 2*N of them).

But there's a more subtle problem. Adding to the existing
array means we might need to grow it with realloc, which
could move the earlier entries around. While many of the
references to other entries are done by integer index,
some (including ones on the stack) use pointers, which
would become invalidated.

This isn't insurmountable, but it would require quite a
bit of refactoring (and it's hard to know that you've got
it all, since it may work _most_ of the time and then
fail subtly based on memory allocation patterns).

- we could allocate a new one-off entry for the base. In
fact, this is what an earlier version of this patch did.
However, since the refactoring brought in by ad635e82d6
(Merge branch 'nd/pack-objects-pack-struct', 2018-05-23),
the delta_idx code requires that both entries be in the
main packing list.

So taking all of those options into account, what I ended up
with is a separate list of "external bases" that are not
part of the main packing list. Each delta entry that points
to an external base has a single-bit flag to do so; we have a
little breathing room in the bitfield section of
object_entry.

This lets us limit the change primarily to the oe_delta()
and oe_set_delta_ext() functions. And as a bonus, most of
the rest of the code does not consider these dummy entries
at all, saving both runtime CPU and code complexity.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pack-bitmap: save "have" bitmap from walk

When we do a bitmap walk, we save the result, which
represents (WANTs & ~HAVEs); i.e., every object we care
about visiting in our walk. However, we throw away the
haves bitmap, which can sometimes be useful, too. Save it
and provide an access function so code which has performed a
walk can query it.

A few notes on the accessor interface:

- the bitmap code calls these "haves" because it grew out
of the want/have negotiation for fetches. But really,
these are simply the objects that would be flagged
UNINTERESTING in a regular traversal. Let's use that
more universal nomenclature for the external module
interface. We may want to change the internal naming
inside the bitmap code, but that's outside the scope of
this patch.

- it still uses a bare "sha1" rather than "oid". That's
true of all of the bitmap code. And in this particular
instance, our caller in pack-objects is dealing with the
bare sha1 that comes from a packed REF_DELTA (we're
pointing directly to the mmap'd pack on disk). That's
something we'll have to deal with as we transition to a
new hash, but we can wait and see how the caller ends up
being fixed and adjust this interface accordingly.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

test-tool.h: include git-compat-util.h

The test-tool programs include "test-tool.h" as their first
include, which breaks our CodingGuideline of "the first
include must be git-compat-util.h or an equivalent".

Rather than change them all, let's instead make test-tool.h
one of those equivalents, just like we do for builtin.h
(which many of the actual git builtins include first).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tests: use 'test_must_be_empty' instead of 'test_cmp <empty> <out>'

Using 'test_must_be_empty' is shorter and more idiomatic than

>empty &&
test_cmp empty out

as it saves the creation of an empty file. Furthermore, sometimes the
expected empty file doesn't have such a descriptive name like 'empty',
and its creation is far away from the place where it's finally used
for comparison (e.g. in 't7600-merge.sh', where two expected empty
files are created in the 'setup' test, but are used only about 500
lines later).

These cases were found by instrumenting 'test_cmp' to error out the
test script when it's used to compare empty files, and then converted
manually.

Note that even after this patch there still remain a lot of cases
where we use 'test_cmp' to check empty files:

- Sometimes the expected output is not hard-coded in the test, but
'test_cmp' is used to ensure that two similar git commands produce
the same output, and that output happens to be empty, e.g. the
test 'submodule update --merge - ignores --merge for new
submodules' in 't7406-submodule-update.sh'.

- Repetitive common tasks, including preparing the expected results
and running 'test_cmp', are often extracted into a helper
function, and some of this helper's callsites expect no output.

- For the same reason as above, the whole 'test_expect_success'
block is within a helper function, e.g. in 't3070-wildmatch.sh'.

- Or 'test_cmp' is invoked in a loop, e.g. the test 'cvs update
(-p)' in 't9400-git-cvsserver-server.sh'.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tests: use 'test_must_be_empty' instead of 'test_cmp /dev/null <out>'

Using 'test_must_be_empty' is more idiomatic than 'test_cmp /dev/null
out', and its message on error is perhaps a bit more to the point.

This patch was basically created by running:

sed -i -e 's%test_cmp /dev/null%test_must_be_empty%' t[0-9]*.sh

with the exception of the change in 'should not fail in an empty repo'
in 't7401-submodule-summary.sh', where it was 'test_cmp output
/dev/null'.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tests: use 'test_must_be_empty' instead of 'test ! -s'

Using 'test_must_be_empty' is preferable to 'test ! -s', because it
gives a helpful error message if the given file is unexpectedly no
empty, while the latter remains completely silent. Furthermore, it
also catches cases when the given file unexpectedly does not exist at
all.

This patch was created by:

sed -i -e 's/test ! -s/test_must_be_empty/' t[0-9]*.sh

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tests: use 'test_must_be_empty' instead of '! test -s'

Using 'test_must_be_empty' is preferable to '! test -s', because it
gives a helpful error message if the given file is unexpectedly not
empty, while the latter remains completely silent. Furthermore, it
also catches cases when the given file unexpectedly does not exist at
all.

This patch was basically created by:

sed -i -e 's/! test -s/test_must_be_empty/' t[0-9]*.sh

with the following notable exceptions:

- The '! test -s' check in '.gitmodules ignore=dirty suppresses
submodules with untracked content' in 't7508-status.sh' is left
as-is, because it's bogus and, therefore, it's subject of a
dedicated patch.

- The '! test -s' checks in 't9131-git-svn-empty-symlink.sh' and
't9135-git-svn-moved-branch-empty-file.sh' are immediately
preceeded by a 'test -f' to ensure that the files exist in the
first place. 'test_must_be_empty' ensures that as well, so those
'test -f' commands are removed as well.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

parseopt: group literal string alternatives in argument help

This formally clarifies that the "--option=" part is the same for all
alternatives.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

remote: improve argument help for add --mirror

Group the possible values using a pair of parentheses and don't mark
them for translation, as they are literal strings that have to be used
as-is in any locale.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

checkout-index: improve argument help for --stage

Spell out all alternatives and avoid using a numerical range operator,
as it is not mentioned in CodingGuidelines and the resulting string is
still concise. Wrap them in parentheses to document clearly that the
"--stage=" part is common among them.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

generate-cmdlist.sh: collect config from all config.txt files

This script uses Documentation/config.txt as input for "git help
--config" and "git config" completion but it misses the fact that
config.txt includes other txt files. Include all *config.txt as input
when scanning for config keys. This could produce false positives, but
as long as we stick to the blah-config.txt naming convention, we
should be ok.

While at there, move diff.* from config.txt to diff-config.txt where
all other diff config keys are.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

l10n: git.pot: v2.19.0 round 1 (382 new, 30 removed)

Generate po/git.pot from v2.19.0-rc0 for git v2.19.0 l10n round 1.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>

Merge branch 'maint' of git://github.com/git-l10n/git-po

* 'maint' of git://github.com/git-l10n/git-po:
l10n: de.po: translate 108 new messages
l10n: zh_CN: review for git 2.18.0
l10n: sv.po: Update Swedish translation(3608t0f0u)

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>

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>

treewide: use get_all_packs

There are many places in the codebase that want to iterate over
all packfiles known to Git. The purposes are wide-ranging, and
those that can take advantage of the multi-pack-index already
do. So, use get_all_packs() instead of get_packed_git() to be
sure we are iterating over all packfiles.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

packfile: add all_packs list

If a repo contains a multi-pack-index, then the packed_git list
does not contain the packfiles that are covered by the multi-pack-index.
This is important for doing object lookups, abbreviations, and
approximating object count. However, there are many operations that
really want to iterate over all packfiles.

Create a new 'all_packs' linked list that contains this list, starting
with the packfiles in the multi-pack-index and then continuing along
the packed_git linked list.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

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>

midx: stop reporting garbage

When prepare_packed_git is called with the report_garbage method
initialized, we report unexpected files in the objects directory
as garbage. Stop reporting the multi-pack-index and the pack-files
it covers as garbage.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

midx: mark bad packed objects

When an object fails to decompress from a pack-file, we mark the object
as 'bad' so we can retry with a different copy of the object (if such a
copy exists).

Before now, the multi-pack-index did not update the bad objects list for
the pack-files it contains, and we did not check the bad objects list
when reading an object. Now, do both.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

multi-pack-index: store local property

A pack-file is 'local' if it is stored within the usual object
directory. If it is stored in an alternate, it is non-local.

Pack-files are stored using a 'pack_local' member in the packed_git
struct. Add a similar 'local' member to the multi_pack_index struct
and 'local' parameters to the methods that load and prepare multi-
pack-indexes.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

multi-pack-index: provide more helpful usage info

The multi-pack-index builtin has a very simple command-line
interface. Instead of simply reporting usage, give the user a
hint to why the arguments failed.

Reported-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Sync 'ds/multi-pack-index' to v2.19.0-rc0

* ds/multi-pack-index: (23 commits)
midx: clear midx on repack
packfile: skip loading index if in multi-pack-index
midx: prevent duplicate packfile loads
midx: use midx in approximate_object_count
midx: use existing midx when writing new one
midx: use midx in abbreviation calculations
midx: read objects from multi-pack-index
config: create core.multiPackIndex setting
midx: write object offsets
midx: write object id fanout chunk
midx: write object ids in a chunk
midx: sort and deduplicate objects from packfiles
midx: read pack names into array
multi-pack-index: write pack names in chunk
multi-pack-index: read packfile list
packfile: generalize pack directory list
t5319: expand test data
multi-pack-index: load into memory
midx: write header information to lockfile
multi-pack-index: add 'write' verb
...

range-diff: indent special lines as context

The range-diff coloring is a bit fuzzy when it comes to special lines of
a diff, such as indicating new and old files with +++ and ---, as it
would pickup the first character and interpret it for its coloring, which
seems annoying as in regular diffs, these lines are colored bold via
DIFF_METAINFO.

By indenting these lines by a white space, they will be treated as context
which is much more useful, an example [1] on the range diff series itself:

[...]
+ diff --git a/Documentation/git-range-diff.txt b/Documentation/git-range-diff.txt
+ new file mode 100644
+ --- /dev/null
+ +++ b/Documentation/git-range-diff.txt
+@@
++git-range-diff(1)
[...]
+
diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
[...]

The first lines that introduce the new file for the man page will have the
'+' sign colored and the rest of the line will be bold.

The later lines that indicate a change to the Makefile will be treated as
context both in the outer and inner diff, such that those lines stay
regular color.

[1] ./git-range-diff pr-1/dscho/branch-diff-v3...pr-1/dscho/branch-diff-v4
These tags are found at https://github.com/gitgitgadget/git

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

range-diff: make use of different output indicators

This change itself only changes the internal communication and should
have no visible effect to the user. We instruct the diff code that
produces the inner diffs to use other markers instead of the
usual markers for new, old and context lines.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c: add --output-indicator-{new, old, context}

This will prove useful in range-diff in a later patch as we will be able to
differentiate between adding a new file (that line is starting with +++
and then the file name) and regular new lines.

It could also be useful for experimentation in new patch formats, i.e.
we could teach git to emit moved lines with lines other than +/-.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/perf: add perf tests for fetches from a bitmapped server

A server with bitmapped packs can serve a clone very
quickly. However, fetches are not necessarily made any
faster, because we spend a lot less time in object traversal
(which is what bitmaps help with) and more time finding
deltas (because we may have to throw out on-disk deltas if
the client does not have the base).

As a first step to making this faster, this patch introduces
a new perf script to measure fetches into a repo of various
ages from a fully-bitmapped server.

We separately measure the work done by the server (in
pack-objects) and that done by the client (in index-pack).
Furthermore, we measure the size of the resulting pack.

Breaking it down like this (instead of just doing a regular
"git fetch") lets us see how much each side benefits from
any changes. And since we know the pack size, if we estimate
the network speed, then one could calculate a complete
wall-clock time for the operation (though the script does
not do this automatically).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/perf: add infrastructure for measuring sizes

The main objective of scripts in the perf framework is to
run "test_perf", which measures the time it takes to run
some operation. However, it can also be interesting to see
the change in the output size of certain operations.

This patch introduces test_size, which records a single
numeric output from the test and shows it in the aggregated
output (with pretty printing and relative size comparison).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/perf: factor out percent calculations

This will let us reuse the code when we add new values to
aggregate besides times.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/perf: factor boilerplate out of test_perf

About half of test_perf() is boilerplate preparing to run
_any_ test, and the other half is specifically running a
timing test. Let's split it into two functions, so that we
can reuse the boilerplate in future commits.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Git 2.19-rc0

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Merge branch 'ab/checkout-default-remote'

* ab/checkout-default-remote:
t2024: mark test using "checkout -p" with PERL prerequisite

Merge branch 'hn/highlight-sideband-keywords'

The sideband code learned to optionally paint selected keywords at
the beginning of incoming lines on the receiving end.

* hn/highlight-sideband-keywords:
sideband: do not read beyond the end of input
sideband: highlight keywords in remote sideband output

Merge branch 'nd/cherry-pick-quit-fix'

"git cherry-pick --quit" failed to remove CHERRY_PICK_HEAD even
though we won't be in a cherry-pick session after it returns, which
has been corrected.

* nd/cherry-pick-quit-fix:
cherry-pick: fix --quit not deleting CHERRY_PICK_HEAD

Merge branch 'sb/submodule-cleanup'

A few preliminary minor clean-ups in the area around submodules.

* sb/submodule-cleanup:
builtin/submodule--helper: remove stray new line
t7410: update to new style

Merge branch 'pw/rebase-i-merge-segv-fix'

"git rebase -i", when a 'merge <branch>' insn in its todo list
fails, segfaulted, which has been (minimally) corrected.

* pw/rebase-i-merge-segv-fix:
rebase -i: fix SIGSEGV when 'merge <branch>' fails
t3430: add conflicting commit

Merge branch 'pw/rebase-i-squash-number-fix'

When "git rebase -i" is told to squash two or more commits into
one, it labeled the log message for each commit with its number.
It correctly called the first one "1st commit", but the next one
was "commit #1", which was off-by-one. This has been corrected.

* pw/rebase-i-squash-number-fix:
rebase -i: fix numbering in squash message

Merge branch 'sb/config-write-fix'

Recent update to "git config" broke updating variable in a
subsection, which has been corrected.

* sb/config-write-fix:
git-config: document accidental multi-line setting in deprecated syntax
config: fix case sensitive subsection names on writing
t1300: document current behavior of setting options

Merge branch 'ab/submodule-relative-url-tests'

Test updates.

* ab/submodule-relative-url-tests:
submodule: add more exhaustive up-path testing

Merge branch 'en/incl-forward-decl'

Code hygiene improvement for the header files.

* en/incl-forward-decl:
Remove forward declaration of an enum
compat/precompose_utf8.h: use more common include guard style
urlmatch.h: fix include guard
Move definition of enum branch_track from cache.h to branch.h
alloc: make allocate_alloc_state and clear_alloc_state more consistent
Add missing includes and forward declarations

Merge branch 'jt/repack-promisor-packs'

After a partial clone, repeated fetches from promisor remote would
have accumulated many packfiles marked with .promisor bit without
getting them coalesced into fewer packfiles, hurting performance.
"git repack" now learned to repack them.

* jt/repack-promisor-packs:
repack: repack promisor objects if -a or -A is set
repack: refactor setup of pack-objects cmd

Merge branch 'wc/make-funnynames-shared-lazy-prereq'

A test prerequisite defined by various test scripts with slightly
different semantics has been consolidated into a single copy and
made into a lazily defined one.

* wc/make-funnynames-shared-lazy-prereq:
t: factor out FUNNYNAMES as shared lazy prereq

Merge branch 'jh/partial-clone-doc'

Doc updates.

* jh/partial-clone-doc:
partial-clone: render design doc using asciidoc

Merge branch 'js/chain-lint-attrfix'

Test fix.

* js/chain-lint-attrfix:
chainlint: fix for core.autocrlf=true

Merge branch 'sb/pull-rebase-submodule'

"git pull --rebase -v" in a repository with a submodule barfed as
an intermediate process did not understand what "-v(erbose)" flag
meant, which has been fixed.

* sb/pull-rebase-submodule:
git-submodule.sh: accept verbose flag in cmd_update to be non-quiet

Merge branch 'js/range-diff'

"git tbdiff" that lets us compare individual patches in two
iterations of a topic has been rewritten and made into a built-in
command.

* js/range-diff: (21 commits)
range-diff: use dim/bold cues to improve dual color mode
range-diff: make --dual-color the default mode
range-diff: left-pad patch numbers
completion: support `git range-diff`
range-diff: populate the man page
range-diff --dual-color: skip white-space warnings
range-diff: offer to dual-color the diffs
diff: add an internal option to dual-color diffs of diffs
color: add the meta color GIT_COLOR_REVERSE
range-diff: use color for the commit pairs
range-diff: add tests
range-diff: do not show "function names" in hunk headers
range-diff: adjust the output of the commit pairs
range-diff: suppress the diff headers
range-diff: indent the diffs just like tbdiff
range-diff: right-trim commit messages
range-diff: also show the diff between patches
range-diff: improve the order of the shown commits
range-diff: first rudimentary implementation
Introduce `range-diff` to compare iterations of a topic branch
...

Merge branch 'nd/no-the-index'

The more library-ish parts of the codebase learned to work on the
in-core index-state instance that is passed in by their callers,
instead of always working on the singleton "the_index" instance.

* nd/no-the-index: (24 commits)
blame.c: remove implicit dependency on the_index
apply.c: remove implicit dependency on the_index
apply.c: make init_apply_state() take a struct repository
apply.c: pass struct apply_state to more functions
resolve-undo.c: use the right index instead of the_index
archive-*.c: use the right repository
archive.c: avoid access to the_index
grep: use the right index instead of the_index
attr: remove index from git_attr_set_direction()
entry.c: use the right index instead of the_index
submodule.c: use the right index instead of the_index
pathspec.c: use the right index instead of the_index
unpack-trees: avoid the_index in verify_absent()
unpack-trees: convert clear_ce_flags* to avoid the_index
unpack-trees: don't shadow global var the_index
unpack-trees: add a note about path invalidation
unpack-trees: remove 'extern' on function declaration
ls-files: correct index argument to get_convert_attr_ascii()
preload-index.c: use the right index instead of the_index
dir.c: remove an implicit dependency on the_index in pathspec code
...

Merge branch 'es/chain-lint-more'

Improve built-in facility to catch broken &&-chain in the tests.

* es/chain-lint-more:
chainlint: add test of pathological case which triggered false positive
chainlint: recognize multi-line quoted strings more robustly
chainlint: let here-doc and multi-line string commence on same line
chainlint: recognize multi-line $(...) when command cuddled with "$("
chainlint: match 'quoted' here-doc tags
chainlint: match arbitrary here-docs tags rather than hard-coded names

Merge branch 'sg/t5310-empty-input-fix'

Test fix.

* sg/t5310-empty-input-fix:
t5310-pack-bitmaps: fix bogus 'pack-objects to file can use bitmap' test

Merge branch 'js/mingw-o-append'

Among the three codepaths we use O_APPEND to open a file for
appending, one used for writing GIT_TRACE output requires O_APPEND
implementation that behaves sensibly when multiple processes are
writing to the same file. POSIX emulation used in the Windows port
has been updated to improve in this area.

* js/mingw-o-append:
mingw: enable atomic O_APPEND

Merge branch 'jk/for-each-object-iteration'

The API to iterate over all objects learned to optionally list
objects in the order they appear in packfiles, which helps locality
of access if the caller accesses these objects while as objects are
enumerated.

* jk/for-each-object-iteration:
for_each_*_object: move declarations to object-store.h
cat-file: use a single strbuf for all output
cat-file: split batch "buf" into two variables
cat-file: use oidset check-and-insert
cat-file: support "unordered" output for --batch-all-objects
cat-file: rename batch_{loose,packed}_object callbacks
t1006: test cat-file --batch-all-objects with duplicates
for_each_packed_object: support iterating in pack-order
for_each_*_object: give more comprehensive docstrings
for_each_*_object: take flag arguments as enum
for_each_*_object: store flag definitions in a single location

Merge branch 'ab/fetch-tags-noclobber'

Test and doc clean-ups.

* ab/fetch-tags-noclobber:
pull doc: fix a long-standing grammar error
fetch tests: correct a comment "remove it" -> "remove them"
push tests: assert re-pushing annotated tags
push tests: add more testing for forced tag pushing
push tests: fix logic error in "push" test assertion
push tests: remove redundant 'git push' invocation
fetch tests: change "Tag" test tag to "testTag"

Merge branch 'ng/mergetool-lose-final-prompt'

"git mergetool" stopped and gave an extra prompt to continue after
the last path has been handled, which did not make much sense.

* ng/mergetool-lose-final-prompt:
mergetool: don't suggest to continue after last file

Merge branch 'jt/commit-graph-per-object-store'

Test update.

* jt/commit-graph-per-object-store:
t5318: avoid unnecessary command substitutions

Merge branch 'ds/commit-graph-fsck'

Test fix.

* ds/commit-graph-fsck:
t5318: use 'test_cmp_bin' to compare commit-graph files

Merge branch 'jt/fetch-negotiator-skipping'

Test fix.

* jt/fetch-negotiator-skipping:
t5552: suppress upload-pack trace output

Merge branch 'jc/gpg-status'

"git verify-tag" and "git verify-commit" have been taught to use
the exit status of underlying "gpg --verify" to signal bad or
untrusted signature they found.

* jc/gpg-status:
gpg-interface: propagate exit status from gpg back to the callers

Merge branch 'jc/update-index-doc'

Doc update.

* jc/update-index-doc:
update-index: there no longer is `apply --index-info`

Merge branch 'en/update-index-doc'

Doc update.

* en/update-index-doc:
git-update-index.txt: reword possibly confusing example

Merge branch 'js/typofixes'

Comment update.

* js/typofixes:
remote-curl: remove spurious period
git-compat-util.h: fix typo

Merge branch 'sk/instaweb-rh-update'

"git instaweb" has been adjusted to run better with newer Apache on
RedHat based distros.

* sk/instaweb-rh-update:
git-instaweb: fix apache2 config with apache >= 2.4
git-instaweb: support Fedora/Red Hat apache module path

Merge branch 'en/t7406-fixes'

Test fixes.

* en/t7406-fixes:
t7406: avoid using test_must_fail for commands other than git
t7406: prefer test_* helper functions to test -[feds]
t7406: avoid having git commands upstream of a pipe
t7406: simplify by using diff --name-only instead of diff --raw
t7406: fix call that was failing for the wrong reason

Merge branch 'js/rebase-merges-exec-fix'

The "--exec" option to "git rebase --rebase-merges" placed the exec
commands at wrong places, which has been corrected.

* js/rebase-merges-exec-fix:
rebase --exec: make it work with --rebase-merges
t3430: demonstrate what -r, --autosquash & --exec should do

Merge branch 'ab/test-must-be-empty-for-master'

Test updates.

* ab/test-must-be-empty-for-master:
tests: make use of the test_must_be_empty function

Merge branch 'ab/newhash-is-sha256'

Documentation update.

* ab/newhash-is-sha256:
doc hash-function-transition: pick SHA-256 as NewHash
doc hash-function-transition: note the lack of a changelog

cache-tree: verify valid cache-tree in the test suite

This makes sure that cache-tree is consistent with the index. The main
purpose is to catch potential problems by saving the index in
unpack_trees() but the line in write_index() would also help spot
missing invalidation in other code.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

unpack-trees: add missing cache invalidation

Any changes to the output index should be (confusingly) marked in the
source index with invalidate_ce_path(). This is used to make sure we
still have valid untracked cache and cache-tree extensions in the end.

We do a pretty good job of invalidating except in two places.
verify_clean_subdirectory() is part of verify_absent() and
verify_absent_sparse(). The former is usually called by merged_entry()
or directly in threeway_merge(). The latter is obviously used by
sparse checkout.

In these three call sites, only merged_entry() follows up with
invalidate_ce_path(). The other two don't, but they should not trigger
this ce removal because this is about D/F conflicts [1]. But let's be
safe and invalidate_ce_path() here as well.

The second place is keep_entry() which is also used by threeway_merge()
to keep higher stage entries. In order to reuse cache-tree we need to
invalidate these paths as well. It's not a problem in the past because
whenever a higher stage entry is present, cache-tree will not be
created [2]. Now we salvage cache-tree even when higher stage entries
are present, we need more invalidation.

[1] c81935348b (Fix switching to a branch with D/F when current branch
has file D. - 2007-03-15)

[2] This is probably too strict. We should be able to create and save
cache-tree for the directories that do not have conflict entries
in cache_tree_update(). And this becomes more important when
cache-tree plays bigger role in terms of performance.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

unpack-trees: reuse (still valid) cache-tree from src_index

We do n-way merge by walking the source index and n trees at the same
time and add merge results to a new temporary index called o->result.
The merge result for any given path could be either

- keep_entry(): same old index entry in o->src_index is reused
- merged_entry(): either a new entry is added, or an existing one updated
- deleted_entry(): one entry from o->src_index is removed

For some reason [1] we keep making sure that the source index's
cache-tree is still valid if used by o->result: for all those
merged/deleted entries, we invalidate the same path in o->src_index,
so only cache-trees covering the "keep_entry" parts remain good.

Because of this, the cache-tree from o->src_index can be perfectly
reused in o->result. And in fact we already rely on this logic to
reuse untracked cache in edf3b90553 (unpack-trees: preserve index
extensions - 2017-05-08). Move the cache-tree to o->result before
doing cache_tree_update() to reduce hashing cost.

Since cache_tree_update() has risen up as one of the most expensive
parts in unpack_trees() after the last few patches. This does help
reduce unpack_trees() time significantly (on webkit.git):

before after
--------------------------------------------------------------------
0.080394752 0.051258167 s: read cache .git/index
0.216010838 0.212106298 s: preload index
0.008534301 0.280521764 s: refresh index
0.251992198 0.218160442 s: traverse_trees
0.377031383 0.374948191 s: check_updates
0.372768105 0.037040114 s: cache_tree_update
1.045887251 0.672031609 s: unpack_trees
0.314983512 0.317456290 s: write index, changed mask = 2e
0.062572653 0.038382654 s: traverse_trees
0.000022544 0.000042731 s: check_updates
0.073795585 0.050930053 s: unpack_trees
0.073807557 0.051099735 s: diff-index
1.938191592 1.614241153 s: git command: git checkout -

[1] I'm pretty sure the reason is an oversight in 34110cd4e3 (Make
'unpack_trees()' have a separate source and destination index -
2008-03-06). That patch aims to _not_ update the source index at
all. The invalidation should have been done on o->result in that
patch. But then there was no cache-tree on o->result even then so
it's pointless to do so.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

unpack-trees: reduce malloc in cache-tree walk

This is a micro optimization that probably only shines on repos with
deep directory structure. Instead of allocating and freeing a new
cache_entry in every iteration, we reuse the last one and only update
the parts that are new each iteration.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

unpack-trees: optimize walking same trees with cache-tree

In order to merge one or many trees with the index, unpack-trees code
walks multiple trees in parallel with the index and performs n-way
merge. If we find out at start of a directory that all trees are the
same (by comparing OID) and cache-tree happens to be available for
that directory as well, we could avoid walking the trees because we
already know what these trees contain: it's flattened in what's called
"the index".

The upside is of course a lot less I/O since we can potentially skip
lots of trees (think subtrees). We also save CPU because we don't have
to inflate and apply the deltas. The downside is of course more
fragile code since the logic in some functions are now duplicated
elsewhere.

"checkout -" with this patch on webkit.git (275k files):

baseline new
--------------------------------------------------------------------
0.056651714 0.080394752 s: read cache .git/index
0.183101080 0.216010838 s: preload index
0.008584433 0.008534301 s: refresh index
0.633767589 0.251992198 s: traverse_trees
0.340265448 0.377031383 s: check_updates
0.381884638 0.372768105 s: cache_tree_update
1.401562947 1.045887251 s: unpack_trees
0.338687914 0.314983512 s: write index, changed mask = 2e
0.411927922 0.062572653 s: traverse_trees
0.000023335 0.000022544 s: check_updates
0.423697246 0.073795585 s: unpack_trees
0.423708360 0.073807557 s: diff-index
2.559524127 1.938191592 s: git command: git checkout -

Another measurement from Ben's running "git checkout" with over 500k
trees (on the whole series):

baseline new
----------------------------------------------------------------------
0.535510167 0.556558733 s: read cache .git/index
0.3057373 0.3147105 s: initialize name hash
0.0184082 0.023558433 s: preload index
0.086910967 0.089085967 s: refresh index
7.889590767 2.191554433 s: unpack trees
0.120760833 0.131941267 s: update worktree after a merge
2.2583504 2.572663167 s: repair cache-tree
0.8916137 0.959495233 s: write index, changed mask = 28
3.405199233 0.2710663 s: unpack trees
0.000999667 0.0021554 s: update worktree after a merge
3.4063306 0.273318333 s: diff-index
16.9524923 9.462943133 s: git command: git.exe checkout

This command calls unpack_trees() twice, the first time on 2way merge
and the second 1way merge. In both times, "unpack trees" time is
reduced to one third. Overall time reduction is not that impressive of
course because index operations take a big chunk. And there's that
repair cache-tree line.

PS. A note about cache-tree invalidation and the use of it in this
code.

We do invalidate cache-tree in _source_ index when we add new entries
to the (temporary) "result" index. But we also use the cache-tree from
source index in this optimization. Does this mean we end up having no
cache-tree in the source index to activate this optimization?

The answer is twisted: the order of finding a good cache-tree and
invalidating it matters. In this case we check for a good cache-tree
first in all_trees_same_as_cache_tree(), then we start to merge things
and potentially invalidate that same cache-tree in the process. Since
cache-tree invalidation happens after the optimization kicks in, we're
still good. But we may lose that cache-tree at the very first
call_unpack_fn() call in traverse_by_cache_tree().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

unpack-trees: add performance tracing

We're going to optimize unpack_trees() a bit in the following
patches. Let's add some tracing to measure how long it takes before
and after. This is the baseline ("git checkout -" on webkit.git, 275k
files on worktree)

performance: 0.056651714 s: read cache .git/index
performance: 0.183101080 s: preload index
performance: 0.008584433 s: refresh index
performance: 0.633767589 s: traverse_trees
performance: 0.340265448 s: check_updates
performance: 0.381884638 s: cache_tree_update
performance: 1.401562947 s: unpack_trees
performance: 0.338687914 s: write index, changed mask = 2e
performance: 0.411927922 s: traverse_trees
performance: 0.000023335 s: check_updates
performance: 0.423697246 s: unpack_trees
performance: 0.423708360 s: diff-index
performance: 2.559524127 s: git command: git checkout -

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>