notes: convert internal parts to struct object_id

Convert several portions of the internals of the code to struct
object_id. Introduce two macros to denote the different constants in
the code: KEY_INDEX for the last byte of the object ID, and
FANOUT_PATH_SEPARATORS for the number of possible path separators (on
Unix, "/"). While these constants are both 19 (one less than the number
of bytes in the hash), distinguish them to make the code more
understandable, and define them logically based on their intended
purpose.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

notes: convert internal structures to struct object_id

Convert the internal structures using unsigned char [20] to take
struct object_id using the following semantic patch and the standard
object_id transforms:

@@
struct leaf_node E1;
@@
- E1.key_sha1
+ E1.key_oid.hash

@@
struct leaf_node *E1;
@@
- E1->key_sha1
+ E1->key_oid.hash

@@
struct leaf_node E1;
@@
- E1.key_sha1
+ E1.key_oid.hash

@@
struct leaf_node *E1;
@@
- E1->key_sha1
+ E1->key_oid.hash

@@
struct non_note E1;
@@
- E1.sha1
+ E1.oid.hash

@@
struct non_note *E1;
@@
- E1->sha1
+ E1->oid.hash

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

grep: add support for PCRE v2

Add support for v2 of the PCRE API. This is a new major version of
PCRE that came out in early 2015[1].

The regular expression syntax is the same, but while the API is
similar, pretty much every function is either renamed or takes
different arguments. Thus using it via entirely new functions makes
sense, as opposed to trying to e.g. have one compile_pcre_pattern()
that would call either PCRE v1 or v2 functions.

Git can now be compiled with either USE_LIBPCRE1=YesPlease or
USE_LIBPCRE2=YesPlease, with USE_LIBPCRE=YesPlease currently being a
synonym for the former. Providing both is a compile-time error.

With earlier patches to enable JIT for PCRE v1 the performance of the
release versions of both libraries is almost exactly the same, with
PCRE v2 being around 1% slower.

However after I reported this to the pcre-dev mailing list[2] I got a
lot of help with the API use from Zoltán Herczeg, he subsequently
optimized some of the JIT functionality in v2 of the library.

Running the p7820-grep-engines.sh performance test against the latest
Subversion trunk of both, with both them and git compiled as -O3, and
the test run against linux.git, gives the following results. Just the
/perl/ tests shown:

$ GIT_PERF_REPEAT_COUNT=30 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_MAKE_COMMAND='grep -q LIBPCRE2 Makefile && make -j8 USE_LIBPCRE2=YesPlease CC=~/perl5/installed/bin/gcc NO_R_TO_GCC_LINKER=YesPlease CFLAGS=-O3 LIBPCREDIR=/home/avar/g/pcre2/inst LDFLAGS=-Wl,-rpath,/home/avar/g/pcre2/inst/lib || make -j8 USE_LIBPCRE=YesPlease CC=~/perl5/installed/bin/gcc NO_R_TO_GCC_LINKER=YesPlease CFLAGS=-O3 LIBPCREDIR=/home/avar/g/pcre/inst LDFLAGS=-Wl,-rpath,/home/avar/g/pcre/inst/lib' ./run HEAD~5 HEAD~ HEAD p7820-grep-engines.sh
[...]
Test HEAD~5 HEAD~ HEAD
-----------------------------------------------------------------------------------------------------------------
7820.3: perl grep 'how.to' 0.31(1.10+0.48) 0.21(0.35+0.56) -32.3% 0.21(0.34+0.55) -32.3%
7820.7: perl grep '^how to' 0.56(2.70+0.40) 0.24(0.64+0.52) -57.1% 0.20(0.28+0.60) -64.3%
7820.11: perl grep '[how] to' 0.56(2.66+0.38) 0.29(0.95+0.45) -48.2% 0.23(0.45+0.54) -58.9%
7820.15: perl grep '(e.t[^ ]*|v.ry) rare' 1.02(5.77+0.42) 0.31(1.02+0.54) -69.6% 0.23(0.50+0.54) -77.5%
7820.19: perl grep 'm(ú|u)lt.b(æ|y)te' 0.38(1.57+0.42) 0.27(0.85+0.46) -28.9% 0.21(0.33+0.57) -44.7%

See commit ("perf: add a comparison test of grep regex engines",
2017-04-19) for details on the machine the above test run was executed
on.

Here HEAD~2 is git with PCRE v1 without JIT, HEAD~ is PCRE v1 with
JIT, and HEAD is PCRE v2 (also with JIT). See previous commits of mine
mentioning p7820-grep-engines.sh for more details on the test setup.

For ease of readability, a different run just of HEAD~ (PCRE v1 with
JIT v.s. PCRE v2), again with just the /perl/ tests shown:

[...]
Test HEAD~ HEAD
----------------------------------------------------------------------------------------
7820.3: perl grep 'how.to' 0.21(0.42+0.52) 0.21(0.31+0.58) +0.0%
7820.7: perl grep '^how to' 0.25(0.65+0.50) 0.20(0.31+0.57) -20.0%
7820.11: perl grep '[how] to' 0.30(0.90+0.50) 0.23(0.46+0.53) -23.3%
7820.15: perl grep '(e.t[^ ]*|v.ry) rare' 0.30(1.19+0.38) 0.23(0.51+0.51) -23.3%
7820.19: perl grep 'm(ú|u)lt.b(æ|y)te' 0.27(0.84+0.48) 0.21(0.34+0.57) -22.2%

I.e. the two are either neck-to-neck, but PCRE v2 usually pulls ahead,
when it does it's around 20% faster.

A brief note on thread safety: As noted in pcre2api(3) & pcre2jit(3)
the compiled pattern can be shared between threads, but not some of
the JIT context, however the grep threading support does all pattern &
JIT compilation in separate threads, so this code doesn't need to
concern itself with thread safety.

See commit 63e7e9d8b6 ("git-grep: Learn PCRE", 2011-05-09) for the
initial addition of PCRE v1. This change follows some of the same
patterns it did (and which were discussed on list at the time),
e.g. mocking up types with typedef instead of ifdef-ing them out when
USE_LIBPCRE2 isn't defined. This adds some trivial memory use to the
program, but makes the code look nicer.

1. https://lists.exim.org/lurker/message/20150105.162835.0666407a.en.html
2. https://lists.exim.org/lurker/thread/20170419.172322.833ee099.en.html

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

grep: un-break building with PCRE >= 8.32 without --enable-jit

Amend my change earlier in this series ("grep: add support for the
PCRE v1 JIT API", 2017-04-11) to un-break the build on PCRE v1
versions later than 8.31 compiled without --enable-jit.

As explained in that change and a later compatibility change in this
series ("grep: un-break building with PCRE < 8.32", 2017-05-10) the
pcre_jit_exec() function is a faster path to execute the JIT.

Unfortunately there's no compatibility stub for that function compiled
into the library if pcre_config(PCRE_CONFIG_JIT, &ret) would return 0,
and no macro that can be used to check for it, so the only portable
option to support builds without --enable-jit is via a new
NO_LIBPCRE1_JIT=UnfortunatelyYes Makefile option[1].

Another option would be to make the JIT opt-in via
USE_LIBPCRE1_JIT=YesPlease, after all it's not a default option of
PCRE v1.

I think it makes more sense to make it opt-out since even though it's
not a default option, most packagers of PCRE seem to turn it on by
default, with the notable exception of the MinGW package.

Make the MinGW platform work by default by changing the build defaults
to turn on NO_LIBPCRE1_JIT=UnfortunatelyYes. It is the only platform
that turns on USE_LIBPCRE=YesPlease by default, see commit
df5218b4c3 ("config.mak.uname: support MSys2", 2016-01-13) for that
change.

1. "How do I support pcre1 JIT on all
versions?" (https://lists.exim.org/lurker/thread/20170601.103148.10253788.en.html)

2. https://github.com/Alexpux/MINGW-packages/blob/master/mingw-w64-pcre/PKGBUILD
(referenced from "Re: PCRE v2 compile error, was Re: What's cooking
in git.git (May 2017, #01; Mon, 1)";
<alpine.DEB.2.20.1705021756530.3480@virtualbox>)

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

pull: ff --rebase --autostash works in dirty repo

When `git pull --rebase --autostash` in a dirty repository resulted in a
fast-forward, nothing was being autostashed and the pull failed. This
was due to a shortcut to avoid running rebase when we can fast-forward,
but autostash is ignored on that codepath.

Now we will only take the shortcut if autostash is not in effect.
Based on a few tests against the git.git repo, the shortcut does not
seem to give us significant performance benefits, on Linux at least.
Regardless, it is more important to be correct than to be fast.

Signed-off-by: Tyler Brazier <tyler@tylerbrazier.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

send-email: Net::SMTP::starttls was introduced in v2.34

We cannot rely on the starttls method being present in Net::SMTP until
c274b798e6881a941d941808c6d89966975cb8c8 (Merge branch 'ipv6_ssl' of
https://github.com/noxxi/perl-libnet into noxxi-ipv6_ssl, 2014-06-02),
which set the module version to 2.34.

This version was first shipped as part of perl in v5.21.5~169 (Update
libnet to CPAN version 3.01, 2014-10-10).

Noticed on an Ubuntu system with perl 5.18.2-2ubuntu1.1, which
provides Net::SMTP version 2.31. The error message is

Can't locate object method "starttls" via package "Net::SMTP" at /usr/lib/git-core/git-send-email line 1410.

Reported-by: Brandon Williams <bmwill@google.com>
Reported-and-tested-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

doc: rewrite description for rev-parse --short

`git rev-parse --short` is not a generic modifier but just a variant
of `--verify` and considers the given length only as a suggestion to
ensure uniqueness.

Signed-off-by: Andreas Heiduk <asheiduk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fetch.c: respect 'submodule.recurse' option

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

builtin/push.c: respect 'submodule.recurse' option

The closest mapping from the boolean 'submodule.recurse' set to "yes"
to the variety of submodule push modes is "on-demand", so implement that.

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

builtin/grep.c: respect 'submodule.recurse' option

In builtin/grep.c we parse the config before evaluating the command line
options. This makes the task of teaching grep to respect the new config
option 'submodule.recurse' very easy by just parsing that option.

As an alternative I had implemented a similar structure to treat
submodules as the fetch/push command have, including
* aligning the meaning of the 'recurse_submodules' to possible submodule
values RECURSE_SUBMODULES_* as defined in submodule.h.
* having a callback to parse the value and
* reacting to the RECURSE_SUBMODULES_DEFAULT state that was the initial
state.

However all this is not needed for a true boolean value, so let's keep
it simple. However this adds another place where "submodule.recurse" is
parsed.

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

Introduce 'submodule.recurse' option for worktree manipulators

Any command that understands '--recurse-submodules' can have its
default changed to true, by setting the new 'submodule.recurse'
option.

This patch includes read-tree/checkout/reset for working tree
manipulating commands. Later patches will cover other commands.

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

docs/config: mention protocol implications of url.insteadOf

If a URL rewrite switches the protocol to something
nonstandard (like "persistent-https" for "https"), the user
may be bitten by the fact that the default protocol
restrictions are different between the two. Let's drop a
note in insteadOf that points the user in the right
direction.

It would be nice if we could make this work out of the box,
but we can't without knowing the security implications of
the user's rewrite. Only the documentation for a particular
remote helper can advise one way or the other. Since we do
include the persistent-https helper in contrib/ (and since
it was the helper in the real-world case that inspired that
patch), let's also drop a note there.

Suggested-by: Elliott Cable <me@ell.io>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

remote: drop free_refspecs() function

We already have free_refspec(), a public function which does
the same thing as the static free_refspecs(). Let's just
keep one. There are two minor differences between the
functions:

1. free_refspecs() is a noop when the refspec argument is
NULL. This probably doesn't matter in practice. The
nr_refspec parameter would presumably be 0 in that
case, skipping the loop. And free(NULL) is explicitly
OK. But it doesn't hurt for us to port this extra
safety to free_refspec(), as one of the callers passes
a funny "i+1" count.

2. The order of arguments is reversed between the two
functions. This patch uses the already-public order of
free_refspec(), as it matches the argument order on the
parsing side.

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

C style: use standard style for "TRANSLATORS" comments

Change all the "TRANSLATORS: [...]" comments in the C code to use the
regular Git coding style, and amend the style guide so that the
example there uses that style.

This custom style was necessary back in 2010 when the gettext support
was initially added, and was subsequently documented in commit
cbcfd4e3ea ("i18n: mention "TRANSLATORS:" marker in
Documentation/CodingGuidelines", 2014-04-18).

GNU xgettext hasn't had the parsing limitation that necessitated this
exception for almost 3 years. Since its 0.19 release on 2014-06-02
it's been able to recognize TRANSLATOR comments in the standard Git
comment syntax[1].

Usually we'd like to keep compatibility with software that's that
young, but in this case literally the only person who needs to be
using a gettext newer than 3 years old is Jiang Xin (the only person
who runs & commits "make pot" results), so I think in this case we can
make an exception.

This xgettext parsing feature was added after a thread on the Git
mailing list[2] which continued on the bug-gettext[3] list, but we
never subsequently changed our style & styleguide, do so.

There are already longstanding changes in git that use the standard
comment style & have their TRANSLATORS comments extracted properly
without getting the literal "*"'s mixed up in the text, as would
happen before xgettext 0.19.

Commit 7ff2683253 ("builtin-am: implement -i/--interactive",
2015-08-04) added one such comment, which in commit df0617bfa7 ("l10n:
git.pot: v2.6.0 round 1 (123 new, 41 removed)", 2015-09-05) got picked
up in the po/git.pot file with the right format, showing that Jiang
already runs a modern xgettext.

The xgettext parser does not handle the sort of non-standard comment
style that I'm amending here in sequencer.c, but that isn't standard
Git comment syntax anyway. With this change to sequencer.c & "make
pot" the comment in the pot file is now correct:

#. TRANSLATORS: %s will be "revert", "cherry-pick" or
-#. * "rebase -i".
+#. "rebase -i".

1. http://git.savannah.gnu.org/cgit/gettext.git/commit/?id=10af7fe6bd
2. <2ce9ec406501d112e032c8208417f8100bed04c6.1397712142.git.worldhello.net@gmail.com>
(https://public-inbox.org/git/2ce9ec406501d112e032c8208417f8100bed04c6.1397712142.git.worldhello.net@gmail.com/)
3. https://lists.gnu.org/archive/html/bug-gettext/2014-04/msg00016.html

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

submodule--helper: show usage for "-h"

Normal users shouldn't ever call submodule--helper, but it
doesn't hurt to give them a normal usage message if they try
"-h".

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

remote-{ext,fd}: print usage message on invalid arguments

We just say "Expected two arguments" when we get a different
number of arguments, but we can be slightly friendlier.
People shouldn't generally be running remote helpers
themselves, but curious users might say "git remote-ext -h".

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

upload-archive: handle "-h" option early

Normally upload-archive forks off upload-archive--writer to
do the real work, and relays any errors back over the
sideband channel. This is a good thing when the command is
properly invoked remotely via ssh or git-daemon. But it's
confusing to curious users who try "git upload-archive -h".

Let's catch this invocation early and give a real usage
message, rather than spewing "-h does not appear to be a git
repository" amidst packet-lines. The chance of a false
positive due to a real client asking for the repo "-h" is
quite small.

Likewise, we'll catch "-h" in upload-archive--writer. People
shouldn't be invoking it manually, but it doesn't hurt to
give a sane message if they do.

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

credential: handle invalid arguments earlier

The git-credential command only takes one argument: the
operation to perform. If we don't have one, we complain
immediately. But if we have one that we don't recognize, we
don't notice until after we've read the credential from
stdin. This is likely to confuse a user invoking "git
credential -h", as the program will hang waiting for their
input before showing anything.

Let's detect this case early. Likewise, we never noticed
when there are extra arguments beyond the one we're
expecting. Let's catch this with the same conditional.

Note that we don't need to handle "--help" similarly,
because the git wrapper does this before even calling
cmd_credential().

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

am: handle "-h" argument earlier

If the user provides "-h" on the command line, then our
parse_options() invocation will show a usage message and
quit. But if "-h" is the only argument, the git wrapper
behaves specially: it ignores our RUN_SETUP flag and calls
cmd_am() without having done repository setup at all. This
is due to 99caeed05 (Let 'git <command> -h' show usage
without a git dir, 2009-11-09).

Before cmd_am() calls parse_options(), though, it runs a few
other setup functions. One of these is am_state_init(),
which uses git_pathdup() to set up the default rebase-apply
path. But calling git_pathdup() when we haven't done
repository setup will fall back to using ".git". That's
mostly harmless (since we won't use the value anyway), but
is forbidden since b1ef400eec ("setup_git_env: avoid blind
fall-back to ".git"", 2016-10-20), and we now BUG().

We can't easily move that setup to after the parse_options()
call; the point is to set up defaults that are overwritten
by the option parsing. Instead, we'll detect the "-h" case
early and show the usage then. This matches the behavior of
other builtins which have a similar setup-ordering issue
(e.g., git-branch).

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

submodule loading: separate code path for .gitmodules and config overlay

The .gitmodules file is not supposed to have all the options available,
that are available in the configuration so separate it out.

A configuration option such as the hypothetical submodule.color.diff
that determines in which color a submodule change is printed,
is a very user specific thing, that the .gitmodules file should
not tamper with.

The .gitmodules file should only be used for settings that required
to setup the project in which the .gitmodules file is tracked. As the
minimum this would only include the name<->path mapping of the
submodule and its URL and branch.

Any further setting (such as 'fetch.recursesubmodules' or
'submodule.<name>.{update, ignore, shallow}') is not specific
to the project setup requirements, but rather is a distribution
of suggested developer configurations. In other areas of Git
a suggested developer configuration is not transported in-tree
but via other means. In an organisation this could be done
by deploying an opinionated system wide config (/etc/gitconfig)
or by putting the settings in the users home directory when
they start at the organisation. In open source projects this
is often accomplished via extensive READMEs (cf. our
SubmittingPatches/CodingGuidlines).

As a later patch in this series wants to introduce
a generic submodule recursion option, we want to make
sure that switch is not exposed via the gitmodules file.

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

reset/checkout/read-tree: unify config callback for submodule recursion

The callback function is essentially duplicated 3 times. Remove all
of them and offer a new callback function, that lives in submodule.c

By putting the callback function there, we no longer need the function
'set_config_update_recurse_submodules', nor duplicate the global variable
in each builtin as well as submodule.c

In the three builtins we have different 2 ways how to load the .gitmodules
and config file, which are slightly different. git-checkout has to load
the submodule config all the time due to 23b4c7bcc5 (checkout: Use
submodule.*.ignore settings from .git/config and .gitmodules, 2010-08-28)

git-reset and git-read-tree do not respect these diff settings, so loading
the submodule configuration is optional. Also put that into submodule.c
for code deduplication.

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

submodule test invocation: only pass additional arguments

In a later patch we want to introduce a config option to trigger the
submodule recursing by default. As this option should be available and
uniform across all commands that deal with submodules we'd want to test
for this option in the submodule update library.

So instead of calling the whole test set again for
"git -c submodule.recurse foo" instead of "git foo --recurse-submodules",
we'd only want to introduce one basic test that tests if the option is
recognized and respected to not overload the test suite.

Change the test functions by taking only the argument and assemble the
command inside the test function by embedding the arguments into the
command that is "git $arguments --recurse-submodules".

It would be nice to do this for all functions in lib-submodule-update,
but we cannot do that for the non-recursing tests, as there we do not
just pass in a git command but whole functions. (See t3426 for example)

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

submodule recursing: do not write a config variable twice

The command line option for '--recurse-submodules' is implemented
using an OPTION_CALLBACK, which takes both the callback (that sets
the file static global variable) as well as passes the same file
static global variable to the option parsing machinery to assign it.
This is fixed in this commit by passing NULL as the variable. The
callback sets it instead

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

Merge branch 'ab/grep-preparatory-cleanup' into sb/submodule-blanket-recursive

* ab/grep-preparatory-cleanup: (31 commits)
grep: assert that threading is enabled when calling grep_{lock,unlock}
grep: given --threads with NO_PTHREADS=YesPlease, warn
pack-objects: fix buggy warning about threads
pack-objects & index-pack: add test for --threads warning
test-lib: add a PTHREADS prerequisite
grep: move is_fixed() earlier to avoid forward declaration
grep: change internal *pcre* variable & function names to be *pcre1*
grep: change the internal PCRE macro names to be PCRE1
grep: factor test for \0 in grep patterns into a function
grep: remove redundant regflags assignments
grep: catch a missing enum in switch statement
perf: add a comparison test of log --grep regex engines with -F
perf: add a comparison test of log --grep regex engines
perf: add a comparison test of grep regex engines with -F
perf: add a comparison test of grep regex engines
perf: emit progress output when unpacking & building
perf: add a GIT_PERF_MAKE_COMMAND for when *_MAKE_OPTS won't do
grep: add tests to fix blind spots with \0 patterns
grep: prepare for testing binary regexes containing rx metacharacters
grep: add a test helper function for less verbose -f \0 tests
...

completion: add completions for git config commit

Add missing completions for git config:

* commit.cleanup
* commit.gpgSign
* commit.verbose

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Fourth batch for 2.14

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

Merge branch 'dt/unpack-save-untracked-cache-extension'

When "git checkout", "git merge", etc. manipulates the in-core
index, various pieces of information in the index extensions are
discarded from the original state, as it is usually not the case
that they are kept up-to-date and in-sync with the operation on the
main index. The untracked cache extension is copied across these
operations now, which would speed up "git status" (as long as the
cache is properly invalidated).

* dt/unpack-save-untracked-cache-extension:
unpack-trees: preserve index extensions

Merge branch 'js/larger-timestamps'

A follow-up hotfix for a topic already in 'master'.

* js/larger-timestamps:
name-rev: change a "long" variable to timestamp_t

Merge branch 'dk/send-email-avoid-net-smtp-ssl-when-able'

"git send-email" now uses Net::SMTP::SSL, which is obsolete, only
when needed. Recent versions of Net::SMTP can do TLS natively.

* dk/send-email-avoid-net-smtp-ssl-when-able:
send-email: Net::SMTP::SSL is obsolete, use only when necessary

Merge branch 'jc/skip-test-in-the-middle'

A recent update to t5545-push-options.sh started skipping all the
tests in the script when a web server testing is disabled or
unavailable, not just the ones that require a web server. Non HTTP
tests have been salvaged to always run in this script.

* jc/skip-test-in-the-middle:
t5545: enhance test coverage when no http server is installed
test: allow skipping the remainder

Merge branch 'ab/conditional-config-with-symlinks'

The recently introduced "[includeIf "gitdir:$dir"] path=..."
mechansim has further been taught to take symlinks into account.
The directory "$dir" specified in "gitdir:$dir" may be a symlink to
a real location, not something that $(getcwd) may return. In such
a case, a realpath of "$dir" is compared with the real path of the
current repository to determine if the contents from the named path
should be included.

* ab/conditional-config-with-symlinks:
config: match both symlink & realpath versions in IncludeIf.gitdir:*

Merge branch 'jt/fetch-allow-tip-sha1-implicitly'

There is no good reason why "git fetch $there $sha1" should fail
when the $sha1 names an object at the tip of an advertised ref,
even when the other side hasn't enabled allowTipSHA1InWant.

* jt/fetch-allow-tip-sha1-implicitly:
fetch-pack: always allow fetching of literal SHA1s

Merge branch 'jt/send-email-validate-hook'

"git send-email" learned to run sendemail-validate hook to inspect
and reject a message before sending it out.

* jt/send-email-validate-hook:
send-email: support validate hook

Merge branch 'jh/memihash-opt'

perf-test update.

* jh/memihash-opt:
p0004: don't error out if test repo is too small
p0004: don't abort if multi-threaded is too slow
p0004: use test_perf
p0004: avoid using pipes
p0004: simplify calls of test-lazy-init-name-hash

Merge branch 'bp/sub-process-convert-filter'

Code from "conversion using external process" codepath has been
extracted to a separate sub-process.[ch] module.

* bp/sub-process-convert-filter:
convert: update subprocess_read_status() to not die on EOF
sub-process: move sub-process functions into separate files
convert: rename reusable sub-process functions
convert: update generic functions to only use generic data structures
convert: separate generic structures and variables from the filter specific ones
convert: split start_multi_file_filter() into two separate functions
pkt-line: annotate packet_writel with LAST_ARG_MUST_BE_NULL
convert: move packet_write_line() into pkt-line as packet_writel()
pkt-line: add packet_read_line_gently()
pkt-line: fix packet_read_line() to handle len < 0 errors
convert: remove erroneous tests for errno == EPIPE

Merge branch 'bw/forking-and-threading'

The "run-command" API implementation has been made more robust
against dead-locking in a threaded environment.

* bw/forking-and-threading:
usage.c: drop set_error_handle()
run-command: restrict PATH search to executable files
run-command: expose is_executable function
run-command: block signals between fork and execve
run-command: add note about forking and threading
run-command: handle dup2 and close errors in child
run-command: eliminate calls to error handling functions in child
run-command: don't die in child when duping /dev/null
run-command: prepare child environment before forking
string-list: add string_list_remove function
run-command: use the async-signal-safe execv instead of execvp
run-command: prepare command before forking
t0061: run_command executes scripts without a #! line
t5550: use write_script to generate post-update hook

Merge branch 'ab/perf-wildmatch'

Add perf-test for wildmatch.

* ab/perf-wildmatch:
perf: add test showing exponential growth in path globbing
perf: add function to setup a fresh test repo

Merge branch 'bw/pathspec-sans-the-index'

Simplify parse_pathspec() codepath and stop it from looking at the
default in-core index.

* bw/pathspec-sans-the-index:
pathspec: convert find_pathspecs_matching_against_index to take an index
pathspec: remove PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP
ls-files: prevent prune_cache from overeagerly pruning submodules
pathspec: remove PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE flag
submodule: add die_in_unpopulated_submodule function
pathspec: provide a more descriptive die message

Merge branch 'jc/name-rev-lw-tag'

"git describe --contains" penalized light-weight tags so much that
they were almost never considered. Instead, give them about the
same chance to be considered as an annotated tag that is the same
age as the underlying commit would.

* jc/name-rev-lw-tag:
name-rev: favor describing with tags and use committer date to tiebreak
name-rev: refactor logic to see if a new candidate is a better name

treewide: use is_missing_file_error() where ENOENT and ENOTDIR are checked

Using the is_missing_file_error() helper introduced in the previous
step, update all hits from

$ git grep -e ENOENT --and -e ENOTDIR

There are codepaths that only check ENOENT, and it is possible that
some of them should be checking both. Updating them is kept out of
this step deliberately, as we do not want to change behaviour in this
step.

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

compat-util: is_missing_file_error()

Our code often opens a path to an optional file, to work on its
contents when we can successfully open it. We can ignore a failure
to open if such an optional file does not exist, but we do want to
report a failure in opening for other reasons (e.g. we got an I/O
error, or the file is there, but we lack the permission to open).

The exact errors we need to ignore are ENOENT (obviously) and
ENOTDIR (less obvious). Instead of repeating comparison of errno
with these two constants, introduce a helper function to do so.

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

branch test: fix invalid config key access

Fixes the test by changing "branch.s/s/dummy" to "branch.s/s.dummy" which is
the right way of accessing config key "branch.s/s.dummy". Purpose of
this test is to confirm that this key doesn't exist after the branch
"s/s" has been renamed to "s".

Earlier it was trying to access invalid config key and hence was getting
an error. However, this wasn't caught because we were expecting the
command to fail for other reason as mentioned above.

Signed-off-by: Sahil Dua <sahildua2305@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Third batch for 2.14

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

Merge branch 'jk/ignore-broken-tags-when-ignoring-missing-links'

Tag objects, which are not reachable from any ref, that point at
missing objects were mishandled by "git gc" and friends (they
should silently be ignored instead)

* jk/ignore-broken-tags-when-ignoring-missing-links:
revision.c: ignore broken tags with ignore_missing_links

Merge branch 'jk/alternate-ref-optim'

A test allowed both "git push" and "git receive-pack" on the other
end write their traces into the same file. This is OK on platforms
that allows atomically appending to a file opened with O_APPEND,
but on other platforms led to a mangled output, causing
intermittent test failures. This has been fixed by disabling
traces from "receive-pack" in the test.

* jk/alternate-ref-optim:
t5400: avoid concurrent writes into a trace file

Merge branch 'bm/interpret-trailers-cut-line-is-eom'

"git interpret-trailers", when used as GIT_EDITOR for "git commit
-v", looked for and appended to a trailer block at the very end,
i.e. at the end of the "diff" output. The command has been
corrected to pay attention to the cut-mark line "commit -v" adds to
the buffer---the real trailer block should appear just before it.

* bm/interpret-trailers-cut-line-is-eom:
interpret-trailers: honor the cut line

Merge branch 'tg/stash-push-fixup'

The shell completion script (in contrib/) learned "git stash" has
a new "push" subcommand.

* tg/stash-push-fixup:
completion: add git stash push

Merge branch 'pw/rebase-i-regression-fix'

Regression fix to topic recently merged to 'master'.

* pw/rebase-i-regression-fix:
rebase -i: add missing newline to end of message
rebase -i: silence stash apply
rebase -i: fix reflog message

Merge branch 'kn/ref-filter-branch-list'

"git for-each-ref --format=..." with %(HEAD) in the format used to
resolve the HEAD symref as many times as it had processed refs,
which was wasteful, and "git branch" shared the same problem.

* kn/ref-filter-branch-list:
ref-filter: resolve HEAD when parsing %(HEAD) atom

Merge branch 'km/log-showsignature-doc'

* km/log-showsignature-doc:
config.txt: add an entry for log.showSignature

Merge branch 'jk/update-links-in-docs'

A few http:// links that are redirected to https:// in the
documentation have been updated to https:// links.

* jk/update-links-in-docs:
doc: use https links to Wikipedia to avoid http redirects

Merge branch 'ja/do-not-ask-needless-questions'

Git sometimes gives an advice in a rhetorical question that does
not require an answer, which can confuse new users and non native
speakers. Attempt to rephrase them.

* ja/do-not-ask-needless-questions:
git-filter-branch: be more direct in an error message
read-tree -m: make error message for merging 0 trees less smart aleck
usability: don't ask questions if no reply is required

Merge branch 'jk/doc-config-include'

Clarify documentation for include.path and includeIf.<condition>.path
configuration variables.

* jk/doc-config-include:
docs/config: consistify include.path examples
docs/config: avoid the term "expand" for includes
docs/config: give a relative includeIf example
docs/config: clarify include/includeIf relationship

Merge branch 'sg/core-filemode-doc-typofix'

* sg/core-filemode-doc-typofix:
docs/config.txt: fix indefinite article in core.fileMode description

Merge branch 'jk/bug-to-abort'

Introduce the BUG() macro to improve die("BUG: ...").

* jk/bug-to-abort:
usage: add NORETURN to BUG() function definitions
config: complain about --local outside of a git repo
setup_git_env: convert die("BUG") to BUG()
usage.c: add BUG() function

Merge branch 'js/eol-on-ourselves'

Make sure our tests would pass when the sources are checked out
with "platform native" line ending convention by default on
Windows. Some "text" files out tests use and the test scripts
themselves that are meant to be run with /bin/sh, ought to be
checked out with eol=LF even on Windows.

* js/eol-on-ourselves:
t4051: mark supporting files as requiring LF-only line endings
Fix the remaining tests that failed with core.autocrlf=true
t3901: move supporting files into t/t3901/
completion: mark bash script as LF-only
git-new-workdir: mark script as LF-only
Fix build with core.autocrlf=true

Merge branch 'jc/read-tree-empty-with-m'

"git read-tree -m" (no tree-ish) gave a nonsense suggestion "use
--empty if you want to clear the index". With "-m", such a request
will still fail anyway, as you'd need to name at least one tree-ish
to be merged.

* jc/read-tree-empty-with-m:
read-tree: "read-tree -m --empty" does not make sense

Merge branch 'js/plug-leaks'

Fix memory leaks pointed out by Coverity (and people).

* js/plug-leaks: (26 commits)
checkout: fix memory leak
submodule_uses_worktrees(): plug memory leak
show_worktree(): plug memory leak
name-rev: avoid leaking memory in the `deref` case
remote: plug memory leak in match_explicit()
add_reflog_for_walk: avoid memory leak
shallow: avoid memory leak
line-log: avoid memory leak
receive-pack: plug memory leak in update()
fast-export: avoid leaking memory in handle_tag()
mktree: plug memory leaks reported by Coverity
pack-redundant: plug memory leak
setup_discovered_git_dir(): plug memory leak
setup_bare_git_dir(): help static analysis
split_commit_in_progress(): simplify & fix memory leak
checkout: fix memory leak
cat-file: fix memory leak
mailinfo & mailsplit: check for EOF while parsing
status: close file descriptor after reading git-rebase-todo
difftool: address a couple of resource/memory leaks
...

Merge branch 'jk/disable-pack-reuse-when-broken'

"pack-objects" can stream a slice of an existing packfile out when
the pack bitmap can tell that the reachable objects are all needed
in the output, without inspecting individual objects. This
strategy however would not work well when "--local" and other
options are in use, and need to be disabled.

* jk/disable-pack-reuse-when-broken:
t5310: fix "; do" style
pack-objects: disable pack reuse for object-selection options

Merge branch 'bc/object-id'

Conversion from uchar[20] to struct object_id continues.

* bc/object-id: (53 commits)
object: convert parse_object* to take struct object_id
tree: convert parse_tree_indirect to struct object_id
sequencer: convert do_recursive_merge to struct object_id
diff-lib: convert do_diff_cache to struct object_id
builtin/ls-tree: convert to struct object_id
merge: convert checkout_fast_forward to struct object_id
sequencer: convert fast_forward_to to struct object_id
builtin/ls-files: convert overlay_tree_on_cache to object_id
builtin/read-tree: convert to struct object_id
sha1_name: convert internals of peel_onion to object_id
upload-pack: convert remaining parse_object callers to object_id
revision: convert remaining parse_object callers to object_id
revision: rename add_pending_sha1 to add_pending_oid
http-push: convert process_ls_object and descendants to object_id
refs/files-backend: convert many internals to struct object_id
refs: convert struct ref_update to use struct object_id
ref-filter: convert some static functions to struct object_id
Convert struct ref_array_item to struct object_id
Convert the verify_pack callback to struct object_id
Convert lookup_tag to struct object_id
...

Merge branch 'nd/split-index-unshare'

Plug some leaks and updates internal API used to implement the
split index feature to make it easier to avoid such a leak in the
future.

* nd/split-index-unshare:
p3400: add perf tests for rebasing many changes
split-index: add and use unshare_split_index()

Merge branch 'jk/diff-submodule-diff-inline'

"git diff --submodule=diff" now recurses into nested submodules.

* jk/diff-submodule-diff-inline:
diff: recurse into nested submodules for inline diff

Merge branch 'jc/repack-threads'

"git repack" learned to accept the --threads=<n> option and pass it
to pack-objects.

* jc/repack-threads:
repack: accept --threads=<n> and pass it down to pack-objects

Merge branch 'bw/dir-c-stops-relying-on-the-index'

API update.

* bw/dir-c-stops-relying-on-the-index:
dir: convert fill_directory to take an index
dir: convert read_directory to take an index
dir: convert read_directory_recursive to take an index
dir: convert open_cached_dir to take an index
dir: convert is_excluded to take an index
dir: convert prep_exclude to take an index
dir: convert add_excludes to take an index
dir: convert is_excluded_from_list to take an index
dir: convert last_exclude_matching_from_list to take an index
dir: convert dir_add* to take an index
dir: convert get_dtype to take index
dir: convert directory_exists_in_index to take index
dir: convert read_skip_worktree_file_from_index to take an index
dir: stop using the index compatibility macros

Merge branch 'sb/checkout-recurse-submodules'

"git checkout --recurse-submodules" did not quite work with a
submodule that itself has submodules.

* sb/checkout-recurse-submodules:
submodule: properly recurse for read-tree and checkout
submodule: avoid auto-discovery in new working tree manipulator code
submodule_move_head: reuse child_process structure for futher commands

Merge branch 'sb/reset-recurse-submodules'

"git reset" learned "--recurse-submodules" option.

* sb/reset-recurse-submodules:
builtin/reset: add --recurse-submodules switch
submodule.c: submodule_move_head works with broken submodules
submodule.c: uninitialized submodules are ignored in recursive commands
entry.c: submodule recursing: respect force flag correctly

verify_filename(): flip order of checks

The looks_like_pathspec() check is much cheaper than
check_filename(), which actually stats the file. Since
either is sufficient for our return value, we should do the
cheaper one first, potentially short-circuiting the other.

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

verify_filename(): treat ":(magic)" as a pathspec

For commands that take revisions and pathspecs, magic
pathspecs like ":(exclude)foo" require the user to specify
a disambiguating "--", since they do not match a file in the
filesystem, like:

git grep foo -- :(exclude)bar

This makes them more annoying to use than they need to be.
We loosened the rules for wildcards in 28fcc0b71 (pathspec:
avoid the need of "--" when wildcard is used, 2015-05-02).
Let's do the same for pathspecs with long-form magic.

We already handle the short-forms ":/" and ":^" specially in
check_filename(), so we don't need to handle them here. And
in fact, we could do the same with long-form magic, parsing
out the actual filename and making sure it exists. But there
are a few reasons not to do it that way:

- the parsing gets much more complicated, and we'd want to
hand it off to the pathspec code. But that code isn't
ready to do this kind of speculative parsing (it's happy
to die() when it sees a syntactically invalid pathspec).

- not all pathspec magic maps to a filesystem path. E.g.,
:(attr) should be treated as a pathspec regardless of
what is in the filesystem

- we can be a bit looser with ":(" than with the
short-form ":/", because it is much less likely to have
a false positive. Whereas ":/" also means "search for a
commit with this regex".

Note that because the change is in verify_filename() and not
in its helper check_filename(), this doesn't affect the
verify_non_filename() case. I.e., if an item that matches
our new rule doesn't resolve as an object, we may fallback
to treating it as a pathspec (rather than complaining it
doesn't exist). But if it does resolve (e.g., as a file in
the index that starts with an open-paren), we won't then
complain that it's also a valid pathspec. This matches the
wildcard-exception behavior.

And of course in either case, one can always insert the "--"
to get more precise results.

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

check_filename(): handle ":^" path magic

We special-case "git log :/foo" to work when "foo" exists in
the working tree. But :^ (and its alias :!) do not get the
same treatment, requiring the user to supply a
disambiguating "--". Let's make them work without requiring
the user to type the "--".

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

check_filename(): use skip_prefix

This avoids some magic numbers (and we'll be adding more
similar calls in a minute).

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

check_filename(): refactor ":/" handling

We handle arguments with the ":/" pathspec magic specially,
making sure the name exists at the top-level. We'll want to
handle more pathspec magic in future patches, so let's do a
little rearranging to make that easier.

Instead of relying on an if/else cascade to avoid the
prefix_filename() call, we'll just set prefix to NULL.
Likewise, we'll get rid of the "name" variable entirely, and
just push the "arg" pointer forward to skip past the magic.
That means by the time we get to the prefix-handling, we're
set up appropriately whether we saw ":/" or not.

Note that this does impact the final error message we
produce when stat() fails, as it shows "arg" (which we'll
have modified to skip magic and include the prefix). This is
a good thing; the original message would say something like
"failed to stat ':/foo'", which is confusing (we tried to
stat "foo").

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

t4208: add check for ":/" without matching file

The DWIM magic in check_filename() doesn't just recognize
":/". It actually makes sure that the file it points to
exists. t4208 checks only the case where the path is
present, not the opposite. Since the next patches will be
touching this area, let's add a test to make sure it
continues working.

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

wildmatch test: remove redundant duplicate test

Remove a test line that's exactly the same as the preceding
line.

This was brought in in commit feabcc173b ("Integrate wildmatch to
git", 2012-10-15), these tests are originally copied from rsync.git,
but the duplicate line was never present there, so must have just
snuck in during integration with git by accident.

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

doc: filter-branch does not require re-export of vars

The function `set_ident` in `filter-branch` exported the variables
GIT_(AUTHOR|COMMITTER)_(NAME|EMAIL|DATE) at least since 6f6826c52b in 2007.
Therefore the filter scripts don't need to re-eport them again.

Signed-off-by: Andreas Heiduk <asheiduk@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

grep: un-break building with PCRE < 8.20

Amend my change earlier in this series ("grep: add support for the
PCRE v1 JIT API", 2017-04-11) to un-break the build on PCRE v1
versions earlier than 8.20.

The 8.20 release was the first release to have JIT & pcre_jit_stack in
the headers, so a mock type needs to be provided for it on those
releases.

Now git should compile with all PCRE versions that it supported before
my JIT change.

I've tested it as far back as version 7.5 released on 2008-01-10, once
I got down to version 7.0 it wouldn't build anymore with GCC 7.1.1,
and I couldn't be bothered to anything older than 7.5 as I'm confident
that if the build breaks on those older versions it's not because of
my JIT change.

See the "un-break" change in this series ("grep: un-break building
with PCRE < 8.32", 2017-05-10) for why this isn't squashed into the
main PCRE JIT commit.

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

grep: un-break building with PCRE < 8.32

Amend my change earlier in this series ("grep: add support for the
PCRE v1 JIT API", 2017-04-11) to un-break the build on PCRE v1
versions earlier than 8.32.

The JIT support was added in version 8.20 released on 2011-10-21, but
it wasn't until 8.32 released on 2012-11-30 that the fast code path to
use the JIT via pcre_jit_exec() was added[1] (see also [2]).

This means that versions 8.20 through 8.31 could still use the JIT,
but supporting it on those versions would add to the already verbose
macro soup around JIT support it, and I don't expect that the use-case
of compiling a brand new git against a 5 year old PCRE is particularly
common, and if someone does that they can just get the existing
pre-JIT slow codepath.

So just take the easy way out and disable the JIT on any version older
than 8.32.

The reason this change isn't part of the initial change PCRE JIT
support is to have a cleaner history showing which parts of the
implementation are only used for ancient PCRE versions. This also
makes it easier to revert this change if we ever decide to stop
supporting those old versions.

1. http://www.pcre.org/original/changelog.txt ("28. Introducing a
native interface for JIT. Through this interface, the
compiled[...]")
2. https://bugs.exim.org/show_bug.cgi?id=2121

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

grep: add support for the PCRE v1 JIT API

Change the grep PCRE v1 code to use JIT when available. When PCRE
support was initially added in commit 63e7e9d8b6 ("git-grep: Learn
PCRE", 2011-05-09) PCRE had no JIT support, it was integrated into
8.20 released on 2011-10-21.

Enabling JIT support usually improves performance by more than
40%. The pattern compilation times are relatively slower, but those
relative numbers are tiny, and are easily made back in all but the
most trivial cases of grep. Detailed benchmarks & overview of
compilation times is at: http://sljit.sourceforge.net/pcre.html

With this change the difference in a t/perf/p7820-grep-engines.sh run
is, with just the /perl/ tests shown:

$ GIT_PERF_REPEAT_COUNT=30 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_MAKE_OPTS='-j8 USE_LIBPCRE=YesPlease CC=~/perl5/installed/bin/gcc NO_R_TO_GCC_LINKER=YesPlease CFLAGS=-O3 LIBPCREDIR=/home/avar/g/pcre/inst LDFLAGS=-Wl,-rpath,/home/avar/g/pcre/inst/lib' ./run HEAD~ HEAD p7820-grep-engines.sh
Test HEAD~ HEAD
---------------------------------------------------------------------------------------
7820.3: perl grep 'how.to' 0.35(1.11+0.43) 0.23(0.42+0.46) -34.3%
7820.7: perl grep '^how to' 0.64(2.71+0.36) 0.27(0.66+0.44) -57.8%
7820.11: perl grep '[how] to' 0.63(2.51+0.42) 0.33(0.98+0.39) -47.6%
7820.15: perl grep '(e.t[^ ]*|v.ry) rare' 1.17(5.61+0.35) 0.34(1.08+0.46) -70.9%
7820.19: perl grep 'm(ú|u)lt.b(æ|y)te' 0.43(1.52+0.44) 0.30(0.88+0.42) -30.2%

The conditional support for JIT is implemented as suggested in the
pcrejit(3) man page. E.g. defining PCRE_STUDY_JIT_COMPILE to 0 if it's
not present.

The implementation is relatively verbose because even if
PCRE_CONFIG_JIT is defined only a call to pcre_config() can determine
if the JIT is available, and if so the faster pcre_jit_exec() function
should be called instead of pcre_exec(), and a different (but not
complimentary!) function needs to be called to free pcre1_extra_info.

There's no graceful fallback if pcre_jit_stack_alloc() fails under
PCRE_CONFIG_JIT, instead the program will simply abort. I don't think
this is worth handling gracefully, it'll only fail in cases where
malloc() doesn't work, in which case we're screwed anyway.

That there's no assignment of `p->pcre1_jit_on = 0` when
PCRE_CONFIG_JIT isn't defined isn't a bug. The create_grep_pat()
function allocates the grep_pat allocates it with calloc(), so it's
guaranteed to be 0 when PCRE_CONFIG_JIT isn't defined.

I you're bisecting and find this change, check that your PCRE isn't
older than 8.32. This change intentionally broke really old versions
of PCRE, but that's fixed in follow-up commits.

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

log: add -P as a synonym for --perl-regexp

Add a short -P option as a synonym for the longer --perl-regexp, for
consistency with the options the corresponding grep invocations
accept.

This was intentionally omitted in commit 727b6fc3ed ("log --grep:
accept --basic-regexp and --perl-regexp", 2012-10-03) for unspecified
future use.

Make it consistent with "grep" rather than to keep it open for future
use, and to avoid the confusion of -P meaning different things for
grep & log, as is the case with the -G option.

As noted in the aforementioned commit the --basic-regexp option can't
have a corresponding -G argument, as the log command already uses that
for -G<regex>.

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

grep: skip pthreads overhead when using one thread

Skip the administrative overhead of using pthreads when only using one
thread. Instead take the non-threaded path which would be taken under
NO_PTHREADS.

The threading support was initially added in commit
5b594f457a ("Threaded grep", 2010-01-25) with a hardcoded compile-time
number of 8 threads. Later the number of threads was made configurable
in commit 89f09dd34e ("grep: add --threads=<num> option and
grep.threads configuration", 2015-12-15).

That change did not add any special handling for --threads=1. Now we
take a slightly faster path by skipping thread handling entirely when
1 thread is requested.

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

grep: don't redundantly compile throwaway patterns under threading

Change the pattern compilation logic under threading so that grep
doesn't compile a pattern it never ends up using on the non-threaded
code path, only to compile it again N times for N threads which will
each use their own copy, ignoring the initially compiled pattern.

This redundant compilation dates back to the initial introduction of
the threaded grep in commit 5b594f457a ("Threaded grep",
2010-01-25).

There was never any reason for doing this redundant work other than an
oversight in the initial commit. Jeff King suggested on-list in
<20170414212325.fefrl3qdjigwyitd@sigill.intra.peff.net> that this
might be needed to check the pattern for sanity before threaded
execution commences.

That's not the case. The pattern is compiled under threading in
start_threads() before any concurrent execution has started by calling
pthread_create(), so if the pattern contains an error we still do the
right thing. I.e. die with one error before any threaded execution has
commenced, instead of e.g. spewing out an error for each N threads,
which could be a regression a change like this might inadvertently
introduce.

This change is not meant as an optimization, any performance gains
from this are in the hundreds to thousands of nanoseconds at most. If
we wanted more performance here we could just re-use the compiled
patterns in multiple threads (regcomp(3) is thread-safe), or partially
re-use them and the associated structures in the case of later PCRE
JIT changes.

Rather, it's just to make the code easier to reason about. It's
confusing to debug this under threading & non-threading when the
threading codepaths redundantly compile a pattern which is never used.

The reason the patterns are recompiled is as a side-effect of
duplicating the whole grep_opt structure, which is not thread safe,
writable, and munged during execution. The grep_opt structure then
points to the grep_pat structure where pattern or patterns are stored.

I looked into e.g. splitting the API into some "do & alloc threadsafe
stuff", "spawn thread", "do and alloc non-threadsafe stuff", but the
execution time of grep_opt_dup() & pattern compilation is trivial
compared to actually executing the grep, so there was no point. Even
with the more expensive JIT changes to follow the most expensive PCRE
patterns take something like 0.0X milliseconds to compile at most[1].

The undocumented --debug mode added in commit 17bf35a3c7 ("grep: teach
--debug option to dump the parse tree", 2012-09-13) still works
properly with this change. It only emits debugging info during pattern
compilation, which is now dumped by the pattern compiled just before
the first thread is started.

1. http://sljit.sourceforge.net/pcre.html

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

grep: assert that threading is enabled when calling grep_{lock,unlock}

Change the grep_{lock,unlock} functions to assert that num_threads is
true, instead of only locking & unlocking the pthread mutex lock when
it is.

These functions are never called when num_threads isn't true, this
logic has gone through multiple iterations since the initial
introduction of grep threading in commit 5b594f457a ("Threaded grep",
2010-01-25), but ever since then they'd only be called if num_threads
was true, so this check made the code confusing to read.

Replace the check with an assertion, so that it's clear to the reader
that this code path is never taken unless we're spawning threads.

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

grep: given --threads with NO_PTHREADS=YesPlease, warn

Add a warning about missing thread support when grep.threads or
--threads is set to a non 0 (default) or 1 (no parallelism) value
under NO_PTHREADS=YesPlease.

This is for consistency with the index-pack & pack-objects commands,
which also take a --threads option & are configurable via
pack.threads, and have long warned about the same under
NO_PTHREADS=YesPlease.

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

pack-objects: fix buggy warning about threads

Fix a buggy warning about threads under NO_PTHREADS=YesPlease. Due to
re-using the delta_search_threads variable for both the state of the
"pack.threads" config & the --threads option, setting "pack.threads"
but not supplying --threads would trigger the warning for both
"pack.threads" & --threads.

Solve this bug by resetting the delta_search_threads variable in
git_pack_config(), it might then be set by --threads again and be
subsequently warned about, as the test I'm changing here asserts.

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

pack-objects & index-pack: add test for --threads warning

Add a test for the warning that's emitted when --threads or
pack.threads is provided under NO_PTHREADS=YesPlease. This uses the
new PTHREADS prerequisite.

The assertion for C_LOCALE_OUTPUT in the latter test is currently
redundant, since unlike index-pack the pack-objects warnings aren't
i18n'd. However they might be changed to be i18n'd in the future, and
there's no harm in future-proofing the test.

There's an existing bug in the implementation of pack-objects which
this test currently tests for as-is. Details about the bug & the fix
are included in a follow-up change.

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

test-lib: add a PTHREADS prerequisite

Add a PTHREADS prerequisite which is false when git is compiled with
NO_PTHREADS=YesPlease.

There's lots of custom code that runs when threading isn't available,
but before this prerequisite there was no way to test it.

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

grep: move is_fixed() earlier to avoid forward declaration

Move the is_fixed() function which are currently only used in
compile_regexp() earlier so it can be used in the PCRE family of
functions in a later change.

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

grep: change internal *pcre* variable & function names to be *pcre1*

Change the internal PCRE variable & function names to have a "1"
suffix. This is for preparation for libpcre2 support, where having
non-versioned names would be confusing.

An earlier change in this series ("grep: change the internal PCRE
macro names to be PCRE1", 2017-04-07) elaborates on the motivations
behind this change.

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

grep: change the internal PCRE macro names to be PCRE1

Change the internal USE_LIBPCRE define, & build options flag to use a
naming convention ending in PCRE1, without changing the long-standing
USE_LIBPCRE Makefile flag which enables this code.

This is for preparation for libpcre2 support where having things like
USE_LIBPCRE and USE_LIBPCRE2 in any more places than we absolutely
need to for backwards compatibility with old Makefile arguments would
be confusing.

In some ways it would be better to change everything that now uses
USE_LIBPCRE to use USE_LIBPCRE1, and to make specifying
USE_LIBPCRE (or --with-pcre) an error. This would impose a one-time
burden on packagers of git to s/USE_LIBPCRE/USE_LIBPCRE1/ in their
build scripts.

However I'd like to leave the door open to making
USE_LIBPCRE=YesPlease eventually mean USE_LIBPCRE2=YesPlease,
i.e. once PCRE v2 is ubiquitous enough that it makes sense to make it
the default.

This code and the USE_LIBPCRE Makefile argument was added in commit
63e7e9d8b6 ("git-grep: Learn PCRE", 2011-05-09). At the time there was
no indication that the PCRE project would release an entirely new &
incompatible API around 3 years later.

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

grep: factor test for \0 in grep patterns into a function

Factor the test for \0 in grep patterns into a function. Since commit
9eceddeec6 ("Use kwset in grep", 2011-08-21) any pattern containing a
\0 is considered fixed as regcomp() can't handle it.

This change makes later changes that make use of either has_null() or
is_fixed() (but not both) smaller.

While I'm at it make the comment conform to the style guide, i.e. add
an opening "/*\n".

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

grep: remove redundant regflags assignments

Remove redundant assignments to the "regflags" variable. This variable
is only used set under GREP_PATTERN_TYPE_ERE, so there's no need to
un-set it under GREP_PATTERN_TYPE_{FIXED,BRE,PCRE}.

Back in 5010cb5fcc[1], we did do "opt.regflags &= ~REG_EXTENDED" upon
seeing "-G" on the command line and flipped the bit on upon seeing
"-E", but I think that was perfectly sensible and it would have been a
bug if we didn't. They were part of the command line parsing that
could have seen "-E" on the command line earlier.

When cca2c172 ("git-grep: do not die upon -F/-P when
grep.extendedRegexp is set.", 2011-05-09) switched the command line
parsing to "read into a 'tentatively this is what we saw the last'
variable and then finally commit just once", we didn't touch
opt.regflags for PCRE and FIXED, but we still had to flip regflags
between BRE and ERE, because parsing of grep.extendedregexp
configuration variable directly touched opt.regflags back then, which
was done by b22520a3 ("grep: allow -E and -n to be turned on by
default via configuration", 2011-03-30).

When 84befcd0 ("grep: add a grep.patternType configuration setting",
2012-08-03) introduced extended_regexp_option field, we stopped
flipping regflags while reading the configuration, and that was when
we should have noticed and stopped dropping REG_EXTENDED bit in the
"now we can commit what type to use" helper function.

There is no reason to do this anymore, so stop doing it, more to
reduce "wait this is used under fixed/BRE/PCRE how?" confusion when
reading the code, than to to save ourselves trivial CPU cycles by
removing one assignment.

1. "built-in "git grep"", 2006-04-30.

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

grep: catch a missing enum in switch statement

Add a die(...) to a default case for the switch statement selecting
between grep pattern types under --recurse-submodules.

Normally this would be caught by -Wswitch, but the grep_pattern_type
type is converted to int by going through parse_options(). Changing
the argument type passed to compile_submodule_options() won't work,
the value will just get coerced. The -Wswitch-default warning will
warn about it, but that produces a lot of noise across the codebase,
this potential issue would be drowned in that noise.

Thus catching this at runtime is the least bad option. This won't ever
trigger in practice, but if a new pattern type were to be added this
catches an otherwise silent bug during development.

See commit 0281e487fd ("grep: optionally recurse into submodules",
2016-12-16) for the initial addition of this code.

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

perf: add a comparison test of log --grep regex engines with -F

Add a performance comparison test of log --grepgrep regex engines
given fixed strings.

See the preceding fixed-string t/perf change ("perf: add a comparison
test of grep regex engines with -F", 2017-04-21) for notes about this,
in particular this mostly tests exactly the same codepath now, but
might not in the future:

$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux ./run p4221-log-grep-engines-fixed.sh
[...]
Test this tree
--------------------------------------------------------
4221.1: fixed log --grep='int' 5.99(5.55+0.40)
4221.2: basic log --grep='int' 5.92(5.56+0.31)
4221.3: extended log --grep='int' 6.01(5.51+0.45)
4221.4: perl log --grep='int' 5.99(5.56+0.38)
4221.6: fixed log --grep='uncommon' 5.06(4.76+0.27)
4221.7: basic log --grep='uncommon' 5.02(4.78+0.21)
4221.8: extended log --grep='uncommon' 4.99(4.78+0.20)
4221.9: perl log --grep='uncommon' 5.00(4.72+0.26)
4221.11: fixed log --grep='æ' 5.35(5.12+0.20)
4221.12: basic log --grep='æ' 5.34(5.11+0.20)
4221.13: extended log --grep='æ' 5.39(5.10+0.22)
4221.14: perl log --grep='æ' 5.44(5.16+0.23)

Only the non-ASCII -i case is different:

$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_4221_LOG_OPTS=' -i' ./run p4221-log-grep-engines-fixed.sh
[...]
Test this tree
-----------------------------------------------------------
4221.1: fixed log -i --grep='int' 6.17(5.77+0.35)
4221.2: basic log -i --grep='int' 6.16(5.59+0.39)
4221.3: extended log -i --grep='int' 6.15(5.70+0.39)
4221.4: perl log -i --grep='int' 6.15(5.69+0.38)
4221.6: fixed log -i --grep='uncommon' 5.10(4.88+0.21)
4221.7: basic log -i --grep='uncommon' 5.04(4.76+0.25)
4221.8: extended log -i --grep='uncommon' 5.07(4.82+0.23)
4221.9: perl log -i --grep='uncommon' 5.03(4.78+0.22)
4221.11: fixed log -i --grep='æ' 5.93(5.65+0.25)
4221.12: basic log -i --grep='æ' 5.88(5.62+0.25)
4221.13: extended log -i --grep='æ' 6.02(5.69+0.29)
4221.14: perl log -i --grep='æ' 5.36(5.06+0.29)

See commit ("perf: add a comparison test of grep regex engines",
2017-04-19) for details on the machine the above test run was executed
on.

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

perf: add a comparison test of log --grep regex engines

Add a very basic performance comparison test comparing the POSIX
basic, extended and perl engines with patterns matching log messages
via --grep=<pattern>.

$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux ./run p4220-log-grep-engines.sh
[...]
Test this tree
---------------------------------------------------------------------
4220.1: basic log --grep='how.to' 6.22(6.00+0.21)
4220.2: extended log --grep='how.to' 6.23(5.98+0.23)
4220.3: perl log --grep='how.to' 6.07(5.79+0.25)
4220.5: basic log --grep='^how to' 6.19(5.93+0.22)
4220.6: extended log --grep='^how to' 6.19(5.93+0.23)
4220.7: perl log --grep='^how to' 6.14(5.88+0.24)
4220.9: basic log --grep='[how] to' 6.96(6.65+0.28)
4220.10: extended log --grep='[how] to' 6.96(6.69+0.24)
4220.11: perl log --grep='[how] to' 6.95(6.58+0.33)
4220.13: basic log --grep='\(e.t[^ ]*\|v.ry\) rare' 7.10(6.80+0.27)
4220.14: extended log --grep='(e.t[^ ]*|v.ry) rare' 7.07(6.80+0.26)
4220.15: perl log --grep='(e.t[^ ]*|v.ry) rare' 7.70(7.46+0.22)
4220.17: basic log --grep='m\(ú\|u\)lt.b\(æ\|y\)te' 6.12(5.87+0.24)
4220.18: extended log --grep='m(ú|u)lt.b(æ|y)te' 6.14(5.84+0.26)
4220.19: perl log --grep='m(ú|u)lt.b(æ|y)te' 6.16(5.93+0.20)

With -i:

$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_4220_LOG_OPTS=' -i' ./run p4220-log-grep-engines.sh
[...]
Test this tree
------------------------------------------------------------------------
4220.1: basic log -i --grep='how.to' 6.74(6.41+0.32)
4220.2: extended log -i --grep='how.to' 6.78(6.55+0.22)
4220.3: perl log -i --grep='how.to' 6.06(5.77+0.28)
4220.5: basic log -i --grep='^how to' 6.80(6.57+0.22)
4220.6: extended log -i --grep='^how to' 6.83(6.52+0.29)
4220.7: perl log -i --grep='^how to' 6.16(5.94+0.20)
4220.9: basic log -i --grep='[how] to' 7.87(7.61+0.24)
4220.10: extended log -i --grep='[how] to' 7.85(7.57+0.27)
4220.11: perl log -i --grep='[how] to' 7.03(6.75+0.25)
4220.13: basic log -i --grep='\(e.t[^ ]*\|v.ry\) rare' 8.68(8.41+0.25)
4220.14: extended log -i --grep='(e.t[^ ]*|v.ry) rare' 8.80(8.44+0.28)
4220.15: perl log -i --grep='(e.t[^ ]*|v.ry) rare' 7.85(7.56+0.26)
4220.17: basic log -i --grep='m\(ú\|u\)lt.b\(æ\|y\)te' 6.94(6.68+0.24)
4220.18: extended log -i --grep='m(ú|u)lt.b(æ|y)te' 7.04(6.76+0.24)
4220.19: perl log -i --grep='m(ú|u)lt.b(æ|y)te' 6.26(5.92+0.29)

See commit ("perf: add a comparison test of grep regex engines",
2017-04-19) for details on the machine the above test run was executed
on.

Before commit ("log: make --regexp-ignore-case work with
--perl-regexp", 2017-05-20) this test will almost definitely
fail (depending on the repo) if passed the -i option, since it wasn't
properly supported under PCRE.

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

perf: add a comparison test of grep regex engines with -F

Add a performance comparison test of grep regex engines given fixed
strings.

The current logic in compile_regexp() ignores the engine parameter and
uses kwset() to search for these, so this test shows no difference
between engines right now:

$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux ./run p7821-grep-engines-fixed.sh
[...]
Test this tree
------------------------------------------------
7821.1: fixed grep int 0.56(1.67+0.68)
7821.2: basic grep int 0.57(1.70+0.57)
7821.3: extended grep int 0.59(1.76+0.51)
7821.4: perl grep int 1.08(1.71+0.55)
7821.6: fixed grep uncommon 0.23(0.55+0.50)
7821.7: basic grep uncommon 0.24(0.55+0.50)
7821.8: extended grep uncommon 0.26(0.55+0.52)
7821.9: perl grep uncommon 0.24(0.58+0.47)
7821.11: fixed grep æ 0.36(1.30+0.42)
7821.12: basic grep æ 0.36(1.32+0.40)
7821.13: extended grep æ 0.38(1.30+0.42)
7821.14: perl grep æ 0.35(1.24+0.48)

Only when run with -i via GIT_PERF_7821_GREP_OPTS=' -i' do we avoid
avoid going through the same kwset.[ch] codepath, see the "Even when
-F..." comment in grep.c. This only kicks for the non-ASCII case:

$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_7821_GREP_OPTS=' -i' ./run p7821-grep-engines-fixed.sh
[...]
Test this tree
---------------------------------------------------
7821.1: fixed grep -i int 0.62(2.10+0.57)
7821.2: basic grep -i int 0.68(1.90+0.61)
7821.3: extended grep -i int 0.78(1.94+0.57)
7821.4: perl grep -i int 0.98(1.78+0.74)
7821.6: fixed grep -i uncommon 0.24(0.44+0.64)
7821.7: basic grep -i uncommon 0.25(0.56+0.54)
7821.8: extended grep -i uncommon 0.27(0.62+0.45)
7821.9: perl grep -i uncommon 0.24(0.59+0.49)
7821.11: fixed grep -i æ 0.30(0.96+0.39)
7821.12: basic grep -i æ 0.27(0.92+0.44)
7821.13: extended grep -i æ 0.28(0.90+0.46)
7821.14: perl grep -i æ 0.28(0.74+0.49)

I'm planning to change how fixed-string searching happens. This test
gives a baseline for comparing performance before & after any such
change.

See commit ("perf: add a comparison test of grep regex engines",
2017-04-19) for details on the machine the above test run was executed
on.

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

perf: add a comparison test of grep regex engines

Add a very basic performance comparison test comparing the POSIX
basic, extended and perl engines.

In theory the "basic" and "extended" engines should be implemented
using the same underlying code with a slightly different pattern
parser, but some implementations may not do this. Jump through some
slight hoops to test both, which is worthwhile since "basic" is the
default.

Running this on an i7 3.4GHz Linux 4.9.0-2 Debian testing against a
checkout of linux.git & latest upstream PCRE, both PCRE and git
compiled with -O3 using gcc 7.1.1:

$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux ./run p7820-grep-engines.sh
[...]
Test this tree
---------------------------------------------------------------
7820.1: basic grep 'how.to' 0.34(1.24+0.53)
7820.2: extended grep 'how.to' 0.33(1.23+0.45)
7820.3: perl grep 'how.to' 0.31(1.05+0.56)
7820.5: basic grep '^how to' 0.32(1.24+0.42)
7820.6: extended grep '^how to' 0.33(1.20+0.44)
7820.7: perl grep '^how to' 0.57(2.67+0.42)
7820.9: basic grep '[how] to' 0.51(2.16+0.45)
7820.10: extended grep '[how] to' 0.49(2.20+0.43)
7820.11: perl grep '[how] to' 0.56(2.60+0.43)
7820.13: basic grep '\(e.t[^ ]*\|v.ry\) rare' 0.66(3.25+0.40)
7820.14: extended grep '(e.t[^ ]*|v.ry) rare' 0.65(3.19+0.46)
7820.15: perl grep '(e.t[^ ]*|v.ry) rare' 1.05(5.74+0.34)
7820.17: basic grep 'm\(ú\|u\)lt.b\(æ\|y\)te' 0.34(1.28+0.47)
7820.18: extended grep 'm(ú|u)lt.b(æ|y)te' 0.34(1.38+0.38)
7820.19: perl grep 'm(ú|u)lt.b(æ|y)te' 0.39(1.56+0.44)

Options can also be passed to git-grep via the GIT_PERF_7820_GREP_OPTS
environment variable. There are various modes such as "-v" that have
very different performance profiles, but handling the combinatorial
explosion of testing all those options would make this script much
more complex and harder to maintain. Instead just add the ability to
do one-shot runs with arbitrary options, e.g.:

$ GIT_PERF_REPEAT_COUNT=10 GIT_PERF_LARGE_REPO=~/g/linux GIT_PERF_7820_GREP_OPTS=" -i" ./run p7820-grep-engines.sh
[...]
Test this tree
------------------------------------------------------------------
7820.1: basic grep -i 'how.to' 0.49(1.72+0.38)
7820.2: extended grep -i 'how.to' 0.46(1.64+0.42)
7820.3: perl grep -i 'how.to' 0.44(1.45+0.45)
7820.5: basic grep -i '^how to' 0.47(1.76+0.38)
7820.6: extended grep -i '^how to' 0.47(1.70+0.42)
7820.7: perl grep -i '^how to' 0.65(2.72+0.37)
7820.9: basic grep -i '[how] to' 0.86(3.64+0.42)
7820.10: extended grep -i '[how] to' 0.84(3.62+0.46)
7820.11: perl grep -i '[how] to' 0.73(3.06+0.39)
7820.13: basic grep -i '\(e.t[^ ]*\|v.ry\) rare' 1.63(8.13+0.36)
7820.14: extended grep -i '(e.t[^ ]*|v.ry) rare' 1.64(8.01+0.44)
7820.15: perl grep -i '(e.t[^ ]*|v.ry) rare' 1.44(6.88+0.44)
7820.17: basic grep -i 'm\(ú\|u\)lt.b\(æ\|y\)te' 0.66(2.67+0.44)
7820.18: extended grep -i 'm(ú|u)lt.b(æ|y)te' 0.66(2.67+0.43)
7820.19: perl grep -i 'm(ú|u)lt.b(æ|y)te' 0.59(2.31+0.37)

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

connect.c: fix leak in parse_one_symref_info()

If we successfully parse a symref value like
"HEAD:refs/heads/master", we add the result to a string
list. But because the string list is marked
STRING_LIST_INIT_DUP, the string list code will make a copy
of the string and add the copy.

This patch fixes it by adding the entry with
string_list_append_nodup(), which lets the string list take
ownership of our newly allocated string. There are two
alternatives that seem like they would work, but aren't the
right solution.

The first is to initialize the list with the "NODUP"
initializer. That would avoid the copy, but then the string
list would not realize that it owns the strings. When we
eventually call string_list_clear(), it would not free the
strings, causing a leak.

The second option would be to use the normal
string_list_append(), but free the local copy in our
function. We can't do this because the local copy actually
contains _two_ strings; the symref name and its target. We
point to the target pointer via the "util" field, and its
memory must last as long as the string list does.

You may also wonder whether it's safe to ever free the local
copy, since the target points into it. The answer is yes,
because we duplicate it in annotaate_refs_with_symref_info
before clearing the string list.

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

log: fix memory leak in open_next_file()

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

rerere.c: move error_errno() closer to the source system call

We are supposed to report errno from fopen(). fclose() between fopen()
and the report function could either change errno or reset it.

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

print errno when reporting a system call error

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

wrapper.c: make warn_on_inaccessible() static

After the last patch, this function is not used outside anymore. Keep it
static.

Noticed-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>