grep: fix NO_LIBPCRE1_JIT to fully disable JIT

If you have a pcre1 library which is compiled with JIT enabled then
PCRE_STUDY_JIT_COMPILE will be defined whether or not the
NO_LIBPCRE1_JIT configuration is set.

This means that we enable JIT functionality when calling pcre_study
even if NO_LIBPCRE1_JIT has been explicitly set and we just use plain
pcre_exec later.

Fix this by using own macro (GIT_PCRE_STUDY_JIT_COMPILE) which we set to
PCRE_STUDY_JIT_COMPILE only if NO_LIBPCRE1_JIT is not set and define to
0 otherwise, as before.

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

grep: fix erroneously copy/pasted variable in check/assert pattern

Fix an erroneously copy/pasted check for the pcre2_jit_stack variable
to check pcre2_match_context instead. The former was already checked
in the preceding "if" statement.

This is a trivial and obvious error introduced in my commit
94da9193a6 ("grep: add support for PCRE v2", 2017-06-01).

In practice if pcre2_match_context_create() returned NULL we were
likely in a situation where malloc() was returning NULL, and were thus
screwed anyway, but if only the pcre2_match_context_create() call
returned NULL (through some transitory bug) PCRE v2 would just
allocate and supply its own context object when matching, and we'd run
normally at the trivial expense of not getting a slight speedup by
sharing the context object between successive matches.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.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>

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>

perf: emit progress output when unpacking & building

Amend the t/perf/run output so that in addition to the "Running N
tests" heading currently being emitted, it also emits "Unpacking $rev"
and "Building $rev" when setting up the build/$rev directory & when
building it, respectively.

This makes it easier to see what's going on and what revision is being
tested as the output scrolls by.

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

perf: add a GIT_PERF_MAKE_COMMAND for when *_MAKE_OPTS won't do

Add a git GIT_PERF_MAKE_COMMAND variable to compliment the existing
GIT_PERF_MAKE_OPTS facility. This allows specifying an arbitrary shell
command to execute instead of 'make'.

This is useful e.g. in cases where the name, semantics or defaults of
a Makefile flag have changed over time. It can even be used to change
the contents of the tree, useful for monkeypatching ancient versions
of git to get them to build.

This opens Pandora's box in some ways, it's now possible to
"jailbreak" the perf environment and e.g. modify the source tree via
this arbitrary instead of just issuing a custom "make" command, such a
command has to be re-entrant in the sense that subsequent perf runs
will re-use the possibly modified tree.

It would be pointless to try to mitigate or work around that caveat in
a tool purely aimed at Git developers, so this change makes no attempt
to do so.

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

grep: add tests to fix blind spots with \0 patterns

Address a big blind spot in the tests for patterns containing \0. The
is_fixed() function considers any string that contains \0 fixed, even
if it contains regular expression metacharacters, those patterns are
currently matched with kwset.

Before this change removing that memchr(s, 0, len) check from
is_fixed() wouldn't change the result of any of the tests, since
regcomp() will happily match the part before the \0.

The kwset path is dependent on whether the the -i flag is on, and
whether the pattern has any non-ASCII characters, but none of this was
tested for.

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

grep: prepare for testing binary regexes containing rx metacharacters

Add setup code needed for testing regexes that contain both binary
data and regex metacharacters.

The POSIX regcomp() function inherently can't support that, because it
takes a \0-delimited char *, but other regex engines APIs like PCRE v2
take a pattern/length pair, and are thus able to handle \0s in
patterns as well as any other character.

When kwset was imported in commit 9eceddeec6 ("Use kwset in grep",
2011-08-21) this limitation was fixed, but at the expense of
introducing the undocumented limitation that any pattern containing \0
implicitly becomes a fixed match (equivalent to -F having been
provided).

That's not something we'd like to keep in the future. The inability to
match patterns containing \0 is a leaky implementation detail.

So add tests as a first step towards changing that. In order to test
that \0-patterns can properly match as regexes the test string needs
to have some regex metacharacters in it.

There were other blind spots in the tests. The code around kwset
specially handles case-insensitive & non-ASCII data, but there were no
tests for this.

Fix all of that by amending the text being matched to contain both
regex metacharacters & non-ASCII data.

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

grep: add a test helper function for less verbose -f \0 tests

Add a helper function to make the tests which check for patterns with
\0 in them more succinct. Right now this isn't a big win, but
subsequent commits will add a lot more of these tests.

The helper is based on the match() function in t3070-wildmatch.sh.

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

grep: add tests for grep pattern types being passed to submodules

Add testing for grep pattern types being correctly passed to
submodules. The pattern "(.|.)[\d]" matches differently under
fixed (not at all), and then matches different lines under
basic/extended & perl regular expressions, so this change asserts that
the pattern type is passed along correctly.

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

grep: amend submodule recursion test for regex engine testing

Amend the submodule recursion test to prepare it for subsequent tests
of whether it passes along the grep.patternType to the submodule
greps.

This is the result of searching & replacing:

foobar -> (1|2)d(3|4)
foo -> (1|2)
bar -> (3|4)

Currently there's no tests for whether e.g. -P or -E is correctly
passed along, tests for that will be added in a follow-up change, but
first add content to the tests which will match differently under
different regex engines.

Reuse the pattern established in an earlier commit of mine in this
series ("log: add exhaustive tests for pattern style options &
config", 2017-04-07). The pattern "(.|.)[\d]" will match this content
differently under fixed/basic/extended & perl.

This test code was originally added in commit 0281e487fd ("grep:
optionally recurse into submodules", 2016-12-16).

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

grep: add tests for --threads=N and grep.threads

Add tests for --threads=N being supplied on the command-line, or when
grep.threads=N being supplied in the configuration.

When the threading support was made run-time configurable in commit
89f09dd34e ("grep: add --threads=<num> option and grep.threads
configuration", 2015-12-15) no tests were added for it.

In developing a change to the grep code I was able to make
'--threads=1 <pat>` segfault, while the test suite still passed. This
change fixes that blind spot in the tests.

In addition to asserting that asking for N threads shouldn't segfault,
test that the grep output given any N is the same.

The choice to test only 1..10 as opposed to 1..8 or 1..16 or whatever
is arbitrary. Testing 1..1024 works locally for me (but gets
noticeably slower as more threads are spawned). Given the structure of
the code there's no reason to test an arbitrary number of threads,
only 0, 1 and >=2 are special modes of operation.

A later patch introduces a PTHREADS test prerequisite which is true
under NO_PTHREADS=UnfortunatelyYes, but even under NO_PTHREADS it's
fine to test --threads=N, we'll just ignore it and not use
threading. So these tests also make sense under that mode to assert
that --threads=N without pthreads still returns expected results.

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

grep: change non-ASCII -i test to stop using --debug

Change a non-ASCII case-insensitive test case to stop using --debug,
and instead simply test for the expected results.

The test coverage remains the same with this change, but the test
won't break due to internal refactoring.

This test was added in commit 793dc676e0 ("grep/icase: avoid kwsset
when -F is specified", 2016-06-25). It was asserting that the regex
must be compiled with compile_fixed_regexp(), instead test for the
expected results, allowing the underlying implementation to change.

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

grep: add a test for backreferences in PCRE patterns

Add a test for backreferences such as (.)\1 in PCRE patterns. This
test ensures that the PCRE_NO_AUTO_CAPTURE option isn't turned
on. Before this change turning it on would break these sort of
patterns, but wouldn't break any tests.

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

grep: add a test asserting that --perl-regexp dies when !PCRE

Add a test asserting that when --perl-regexp (and -P for grep) is
given to git-grep & git-log that we die with an error.

In developing the PCRE v2 series I introduced a regression where -P
would (through control-flow fall-through) become synonymous with basic
POSIX matching. I.e. 'git grep -P '[\d]' would match "d" instead of
digits.

The entire test suite would still pass with this serious regression,
since everything that tested for --perl-regexp would be guarded by the
PCRE prerequisite, fix that blind-spot by adding tests under !PCRE
asserting that git must die when given --perl-regexp or -P.

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

log: make --regexp-ignore-case work with --perl-regexp

Make the --regexp-ignore-case option work with --perl-regexp. This
never worked, and there was no test for this. Fix the bug and add a
test.

When PCRE support was added in commit 63e7e9d8b6 ("git-grep: Learn
PCRE", 2011-05-09) compile_pcre_regexp() would only check
opt->ignore_case, but when the --perl-regexp option was added in
commit 727b6fc3ed ("log --grep: accept --basic-regexp and
--perl-regexp", 2012-10-03) the code didn't set the opt->ignore_case.

Change the test suite to test for -i and --invert-regexp with
basic/extended/perl patterns in addition to fixed, which was the only
patternType that was tested for before in combination with those
options.

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

log: add exhaustive tests for pattern style options & config

Add exhaustive tests for how the different grep.patternType options &
the corresponding command-line options affect git-log.

Before this change it was possible to patch revision.c so that the
--basic-regexp option was synonymous with --extended-regexp, and
--perl-regexp wasn't recognized at all, and still have 100% of the
test suite pass.

This was because the first test being modified here, added in commit
34a4ae55b2 ("log --grep: use the same helper to set -E/-F options as
"git grep"", 2012-10-03), didn't actually check whether we'd enabled
extended regular expressions as distinct from re-toggling non-fixed
string support.

Fix that by changing the pattern to a pattern that'll only match if
--extended-regexp option is provided, but won't match under the
default --basic-regexp option.

Other potential regressions were possible since there were no tests
for the rest of the combinations of grep.patternType configuration
toggles & corresponding git-log command-line options. Add exhaustive
tests for those.

The patterns being passed to fixed/basic/extended/PCRE are carefully
crafted to return the wrong thing if the grep engine were to pick any
other matching method than the one it's told to use.

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

test-lib: rename the LIBPCRE prerequisite to PCRE

Rename the LIBPCRE prerequisite to PCRE. This is for preparation for
libpcre2 support, where having just "LIBPCRE" would be confusing as it
implies v1 of the library.

None of these tests are incompatible between versions 1 & 2 of
libpcre, it's less confusing to give them a more general name to make
it clear that they work on both library versions.

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

grep & rev-list doc: stop promising libpcre for --perl-regexp

Stop promising in our grep & rev-list options documentation that we're
always going to be using libpcre when given the --perl-regexp option.

Instead talk about using "Perl-compatible regular expressions" and
using these types of patterns using "a compile-time dependency".

Saying "libpcre" means that we're talking about libpcre.so, which is
always going to be v1. This change is part of an ongoing saga to add
support for libpcre2, which comes with PCRE v2.

In the future we might use some completely unrelated library to
provide perl-compatible regular expression support. By wording the
documentation differently and not promising any specific version of
PCRE or even PCRE at all we have more wiggle room to change the
implementation.

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

Makefile & configure: reword inaccurate comment about PCRE

Reword an outdated & inaccurate comment which suggests that only
git-grep can use PCRE.

This comment was added back when PCRE support was initially added in
commit 63e7e9d8b6 ("git-grep: Learn PCRE", 2011-05-09), and was true
at the time.

It hasn't been telling the full truth since git-log learned to use
PCRE with --grep in commit 727b6fc3ed ("log --grep: accept
--basic-regexp and --perl-regexp", 2012-10-03), and more importantly
is likely to get more inaccurate over time as more use is made of PCRE
in other areas.

Reword it to be more future-proof, and to more clearly explain that
this enables user-initiated runtime behavior.

Copy/pasting this so much in configure.ac is lame, these Makefile-like
flags aren't even used by autoconf, just the corresponding
--with[out]-* options. But copy/pasting the comments that make sense
for the Makefile to configure.ac where they make less sense is the
pattern everything else follows in that file. I'm not going to war
against that as part of this change, just following the existing
pattern.

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

Git 2.13

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

Merge tag 'l10n-2.13.0-rnd2.1' of git://github.com/git-l10n/git-po

l10n for Git 2.13.0 round 2.1

* tag 'l10n-2.13.0-rnd2.1' of git://github.com/git-l10n/git-po:
l10n: zh_CN: for git v2.13.0 l10n round 2
l10n: sv.po: Update Swedish translation (3195t0f0u)
l10n: zh_CN: review for git v2.13.0 l10n round 1
l10n: Update Catalan translation
l10n: bg.po: Updated Bulgarian translation (3195t)
l10n: fr.po v2.13 rnd 2
l10n: de.po: translate 4 new messages
l10n: de.po: update German translation
l10n: de.po: lower case after semi-colon
l10n: vi.po(3195t): Update translation for v2.13.0 round 2
l10n: git.pot: v2.13.0 round 2 (4 new, 7 removed)
l10n: zh_CN: for git v2.13.0 l10n round 1
l10n: fr.po v2.13 round 1
l10n: pt_PT: update Portuguese translation
l10n: bg.po: Updated Bulgarian translation (3201t)
l10n: vi.po(3198t): Updated Vietnamese translation for v2.13.0-rc0
l10n: sv.po: Update Swedish translation (3199t0f0u)
l10n: git.pot: v2.13.0 round 1 (96 new, 37 removed)

Merge branch 'master' of git://github.com/nafmo/git-l10n-sv

* 'master' of git://github.com/nafmo/git-l10n-sv:
l10n: sv.po: Update Swedish translation (3195t0f0u)

l10n: zh_CN: for git v2.13.0 l10n round 2

Translate 4 messages (3195t0f0u) for git v2.13.0-rc2.

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

l10n: sv.po: Update Swedish translation (3195t0f0u)

Signed-off-by: Peter Krefting <peter@softwolves.pp.se>

Sync with v2.12.3

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

Merge branch 'jh/verify-index-checksum-only-in-fsck'

* jh/verify-index-checksum-only-in-fsck:
t1450: avoid use of "sed" on the index, which is a binary file

l10n: zh_CN: review for git v2.13.0 l10n round 1

Signed-off-by: Ray Chen <oldsharp@gmail.com>

Merge branch 'master' of https://github.com/vnwildman/git

* 'master' of https://github.com/vnwildman/git:
l10n: vi.po(3195t): Update translation for v2.13.0 round 2

l10n: Update Catalan translation

Signed-off-by: Jordi Mas <jmas@softcatala.org>

l10n: bg.po: Updated Bulgarian translation (3195t)

Signed-off-by: Alexander Shopov <ash@kambanaria.org>

Merge branch 'fr_l10n_v2.13_rnd2' of git://github.com/jnavila/git

* 'fr_l10n_v2.13_rnd2' of git://github.com/jnavila/git:
l10n: fr.po v2.13 rnd 2

l10n: fr.po v2.13 rnd 2

Signed-off-by: Jean-Noel Avila <jn.avila@free.fr>

l10n: de.po: translate 4 new messages

Translate 4 new messages came from git.pot update in 28e1aaa48 (l10n:
git.pot: v2.13.0 round 2 (4 new, 7 removed)).

Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com>
Acked-by: Matthias Rüster <matthias.ruester@gmail.com>

l10n: de.po: update German translation

Translate 96 new messages came from git.pot update in dfc182b (l10n:
git.pot: v2.13.0 round 1 (96 new, 37 removed)).

Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com>
Acked-by: Matthias Rüster <matthias.ruester@gmail.com>

l10n: de.po: lower case after semi-colon

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com>

l10n: vi.po(3195t): Update translation for v2.13.0 round 2

Signed-off-by: Tran Ngoc Quan <vnwildman@gmail.com>

Git 2.12.3

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

Merge branch 'maint-2.11' into maint

Git 2.11.2

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

Merge branch 'maint-2.10' into maint-2.11

Git 2.10.3

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

Merge branch 'maint-2.9' into maint-2.10

Git 2.9.4

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

Merge branch 'maint-2.8' into maint-2.9

Git 2.8.5

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

Merge branch 'maint-2.7' into maint-2.8

Git 2.7.5

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

Merge branch 'maint-2.6' into maint-2.7

Git 2.6.7

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

Merge branch 'maint-2.5' into maint-2.6

Git 2.5.6

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

Merge branch 'maint-2.4' into maint-2.5

Git 2.4.12

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

Merge branch 'jk/shell-no-repository-that-begins-with-dash' into maint-2.4

* jk/shell-no-repository-that-begins-with-dash:
shell: disallow repo names beginning with dash

shell: disallow repo names beginning with dash

When a remote server uses git-shell, the client side will
connect to it like:

ssh server "git-upload-pack 'foo.git'"

and we literally exec ("git-upload-pack", "foo.git"). In
early versions of upload-pack and receive-pack, we took a
repository argument and nothing else. But over time they
learned to accept dashed options. If the user passes a
repository name that starts with a dash, the results are
confusing at best (we complain of a bogus option instead of
a non-existent repository) and malicious at worst (the user
can start an interactive pager via "--help").

We could pass "--" to the sub-process to make sure the
user's argument is interpreted as a branch name. I.e.:

git-upload-pack -- -foo.git

But adding "--" automatically would make us inconsistent
with a normal shell (i.e., when git-shell is not in use),
where "-foo.git" would still be an error. For that case, the
client would have to specify the "--", but they can't do so
reliably, as existing versions of git-shell do not allow
more than a single argument.

The simplest thing is to simply disallow "-" at the start of
the repo name argument. This hasn't worked either with or
without git-shell since version 1.0.0, and nobody has
complained.

Note that this patch just applies to do_generic_cmd(), which
runs upload-pack, receive-pack, and upload-archive. There
are two other types of commands that git-shell runs:

- do_cvs_cmd(), but this already restricts the argument to
be the literal string "server"

- admin-provided commands in the git-shell-commands
directory. We'll pass along arbitrary arguments there,
so these commands could have similar problems. But these
commands might actually understand dashed arguments, so
we cannot just block them here. It's up to the writer of
the commands to make sure they are safe. With great
power comes great responsibility.

Reported-by: Timo Schmid <tschmid@ernw.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

l10n: git.pot: v2.13.0 round 2 (4 new, 7 removed)

Generate po/git.pot from v2.13.0-rc2 for git v2.13.0 l10n round 2.

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

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

* 'master' of git://github.com/git-l10n/git-po:
l10n: zh_CN: for git v2.13.0 l10n round 1
l10n: fr.po v2.13 round 1
l10n: pt_PT: update Portuguese translation
l10n: bg.po: Updated Bulgarian translation (3201t)
l10n: vi.po(3198t): Updated Vietnamese translation for v2.13.0-rc0
l10n: sv.po: Update Swedish translation (3199t0f0u)
l10n: git.pot: v2.13.0 round 1 (96 new, 37 removed)

l10n: zh_CN: for git v2.13.0 l10n round 1

Translate 96 messages (3198t0f0u) for git v2.13.0-rc0.

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

Merge branch 'fr_l10n_v2.13_rnd1' of git://github.com/jnavila/git

* 'fr_l10n_v2.13_rnd1' of git://github.com/jnavila/git:
l10n: fr.po v2.13 round 1

Git 2.13-rc2

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

Merge branch 'rg/a-the-typo'

Typofix.

* rg/a-the-typo:
fix minor typos

Merge branch 'sr/hooks-cwd-doc'

* sr/hooks-cwd-doc:
githooks.txt: clarify push hooks are always executed in $GIT_DIR

Merge branch 'rg/doc-submittingpatches-wordfix'

* rg/doc-submittingpatches-wordfix:
doc: update SubmittingPatches

Merge branch 'rg/doc-pull-typofix'

* rg/doc-pull-typofix:
doc: git-pull.txt use US spelling, fix minor typo

Merge branch 'ja/i18n-cleanup'

* ja/i18n-cleanup:
i18n: read-cache: typofix
i18n: remove i18n from tag reflog message

l10n: fr.po v2.13 round 1

Signed-off-by: Jean-Noel Avila <jn.avila@free.fr>

l10n: pt_PT: update Portuguese translation

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>

Merging a handful of topics before -rc2

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

Merge branch 'sh/rebase-i-reread-todo-after-exec'

"git rebase -i" failed to re-read the todo list file when the
command specified with the `exec` instruction updated it.

* sh/rebase-i-reread-todo-after-exec:
rebase -i: reread the todo list if `exec` touched it

Merge branch 'ls/travis-stricter-linux32-builds'

32-bit Linux build on Travis CI uses stricter compilation options.

* ls/travis-stricter-linux32-builds:
travis-ci: set DEVELOPER knob for Linux32 build

Merge branch 'ls/travis-win-fix-status'

Relaying status from Windows build by Travis CI was done with an
unsafe invocation of printf.

* ls/travis-win-fix-status:
travis-ci: printf $STATUS as string

Merge branch 'jk/submodule-init-segv-fix'

Fix a segv in 'submodule init' when url is not given for a submodule.

* jk/submodule-init-segv-fix:
submodule_init: die cleanly on submodules without url defined

Merge branch 'jk/prio-queue-avoid-swap-with-self'

Code clean-up.

* jk/prio-queue-avoid-swap-with-self:
prio_queue_reverse: don't swap elements with themselves

Merge branch 'ab/align-perf-descriptions'

Output from perf tests have been updated to align their titles.

* ab/align-perf-descriptions:
t/perf: correctly align non-ASCII descriptions in output

Merge branch 'jk/complete-checkout-sans-dwim-remote'

Completion for "git checkout <branch>" that auto-creates the branch
out of a remote tracking branch can now be disabled, as this
completion often gets in the way when completing to checkout an
existing local branch that happens to share the same prefix with
bunch of remote tracking branches.

* jk/complete-checkout-sans-dwim-remote:
completion: optionally disable checkout DWIM

i18n: read-cache: typofix

Signed-off-by: Peter Krefting <peter@softwolves.pp.se>
Signed-off-by: Jean-Noel Avila <jn.avila@free.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

i18n: remove i18n from tag reflog message

The building of the reflog message is using strbuf, which is not
friendly with internationalization frameworks. No other reflog
messages are translated right now and switching all the messages to
i18n would require a major rework of the way the messages are built.

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

doc: git-pull.txt use US spelling, fix minor typo

Signed-off-by: René Genz <liebundartig@freenet.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>