t: validate 'test_i18ngrep's parameters

Some of the previous patches in this series fixed bogus
'test_i18ngrep' invocations:

- Two invocations where the tested git command's standard output is
directly piped into 'test_i18ngrep'. While convenient, this is an
antipattern, because the pipe hides the git command's exit code,
and the test could continue even if the command exited with error.

- Two invocations that had neither a filename parameter nor anything
piped into their standard input, yet both managed to remain
unnoticed for years. A third similarly bogus invocation is
currently lurking in 'pu' for a couple of weeks now.

Prevent similar mistakes in the future by validating 'test_i18ngrep's
parameters requiring that

- The last parameter names an existing file to be read, effectively
forbidding piping into 'test_i18ngrep'.

Note that this change will also forbid cases where 'test_i18ngrep'
would legitimately read its standard input, e.g. when its standard
input is redirected from a file, or when a git command's standard
output is first written to an intermediate file, which is then
preprocessed by a non-git command before the results are piped
into 'test_i18ngrep'. See two of the previous patches for the
only such cases we had in our test suite. However, reliably
preventing the piping antipattern is arguably more important than
supporting these cases, which can be easily worked around by
opening the file directly or using an intermediate file anyway.

- There are at least two parameters, not including the optional '!'
to negate the pattern. This ought to catch corner cases when
'test_i18ngrep' looks for the name of an existing file on its
standard input; the above check would miss this case becase the
filename as pattern would be the last parameter.

Note that this is not quite perfect, as it doesn't account for any
'grep --options' given as parameters. However, doing so would be
far too complicated, considering that patterns can start with
dashes as well, and in the majority of the cases we don't use any
such options anyway.

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

t: move 'test_i18ncmp' and 'test_i18ngrep' to 'test-lib-functions.sh'

Both 'test_i18ncmp' and 'test_i18ngrep' helper functions are supposed
to be called from our test scripts, so they should be in
'test-lib-functions.sh'.

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

t5536: let 'test_i18ngrep' read the file without redirection

Redirecting 'test_i18ngrep's standard input from a file will interfere
with the linting that will be added in a later patch.

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

t5510: consolidate 'grep' and 'test_i18ngrep' patterns

One of the tests in 't5510-fetch.sh' checks the output of 'git fetch'
using 'test_i18ngrep', and while doing so it prefilters the output
with 'grep' before piping the result into 'test_i18ngrep'.

This prefiltering is unnecessary, with the appropriate pattern
'test_i18ngrep' can do it all by itself. Furthermore, piping data
into 'test_i18ngrep' will interfere with the linting that will be
added in a later patch.

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

t4001: don't run 'git status' upstream of a pipe

The primary purpose of three tests in 't4001-diff-rename.sh' is to
check rename detection in 'git status', but all three do so by running
'git status' upstream of a pipe, hiding its exit code. Consequently,
the test could continue even if 'git status' exited with error.

Use an intermediate file between 'git status' and 'test_i18ngrep' to
catch a potential failure of the former.

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

t6022: don't run 'git merge' upstream of a pipe

The primary purpose of 't6022-merge-rename.sh' is to test 'git merge',
but one of the tests runs it upstream of a pipe, hiding its exit code.
Consequently, the test could continue even if 'git merge' exited with
error.

Use an intermediate file between 'git merge' and 'test_i18ngrep' to
catch a potential failure of the former.

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

t5812: add 'test_i18ngrep's missing filename parameter

The second 'test_i18ngrep' invocation in the test 'curl redirects
respect whitelist' is missing its filename parameter. This has
remained unnoticed since its introduction in f4113cac0 (http: limit
redirection to protocol-whitelist, 2015-09-22), because it would only
cause the test to fail if Git was built with a sufficiently old
libcurl version. The test's two ||-chained 'test_i18ngrep'
invocations are supposed to check that either one of the two patterns
is present in 'git clone's error message. As it happens, the first
invocation covers the error message from any reasonably up-to-date
libcurl, thus the second invocation, the one without the filename
parameter, isn't executed at all. Apparently no one has run the test
suite's httpd tests with such an old libcurl in the last 2+ years, or
at least they haven't bothered to notify us about the failed test.

Fix this by consolidating the two patterns into a single extended
regexp, eliminating the need for an ||-chained second 'test_i18ngrep'
invocation.

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

t5541: add 'test_i18ngrep's missing filename parameter

The test 'push --no-progress silences progress but not status' runs
'test_i18ngrep' without specifying a filename parameter. This has
remained unnoticed since its introduction in e304aeba2 (t5541: test
more combinations of --progress, 2012-05-01), because that
'test_i18ngrep' is supposed to check that the given pattern is not
present in its input, and of course it won't find that pattern if its
input is empty (as it comes from /dev/null). This also means that
this test could miss a potential breakage of 'git push --no-progress'.

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

git-sh-i18n: check GETTEXT_POISON before USE_GETTEXT_SCHEME

Running "make NO_GETTEXT=1 GETTEXT_POISON=1" currently fails
t0205.

While it might seem nonsensical at first glance to both
poison and disable gettext, it's useful to be able to do a
poison test-run on a system that doesn't have gettext at
all. And it works fine for C programs; the problem is only
with the shell code.

The issue is that we check the baked-in USE_GETTEXT_SCHEME
value before GETTEXT_POISON. And when NO_GETTEXT is set, the
Makefile sets USE_GETTEXT_SCHEME to "fallthrough".

So one fix would be to have the Makefile just set
USE_GETTEXT_SCHEME to "poison" if GETTEXT_POISON is set.
But there are two problems with that:

1. USE_GETTEXT_SCHEME is actually a user-facing knob, so
conceivably somebody could override it with:

make USE_GETTEXT_SCHEME=gnu GETTEXT_POISON=1

which would do the wrong thing (though that's much less
likely than them having the variable set in their
config.mak and just overriding GETTEXT_POISON on the
command-line for a one-off test).

2. We don't actually bake GETTEXT_POISON in to the shell
library like we do for the C code. It checks
$GIT_GETTEXT_POISON at runtime, which is set up by the
test suite. So it makes sense to put the fix in the
runtime code, too, which would cover something like:

GIT_GETTEXT_POISON=foo git foo

It's not likely that people use the poison code outside
of running the test suite, but it's easy enough to make
this case work.

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

t0205: drop redundant test

We check that a shell variable is non-empty, and then we
check that it's equal to a particular value. Just checking
the latter covers both cases.

I suspect the original was trying to give better output when
the test fails, but using "-x" covers that these days.

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

blame: tighten command line parser

The command line parser of "git blame" is prepared to take an
ancient odd argument order "blame <path> <rev>" in addition to the
usual "blame [<rev>] <path>". It has at least two negative
ramifications:

- In order to tell these two apart, it checks if the last command
line argument names a path in the working tree, using
file_exists(). However, "blame <rev> <path>" is a request to
explain each and every line in the contents of <path> stored in
revision <rev> and does not need to have a working tree version
of the file. A check with file_exists() is simply wrong.

- To coerce that mistaken file_exists() check to work, the code
calls setup_work_tree() before doing so, because the path it has
is relative to the top-level of the project tree. However,
"blame <rev> <path>" MUST be usable even in a bare repository,
and there is no reason for letting setup_work_tree() complain
and die with "This operation must be run in a work tree".

To correct the former, switch to check if the last token is a
revision (and if so, parse arguments using "blame <path> <rev>"
rule). Correct the latter by getting rid of setup_work_tree() and
file_exists() check--the only case the call to this function matters
is when we are running "blame <path>" (i.e. no starting revision and
asking to blame the working tree file at <path>, digging through the
HEAD revision), but there is a call in setup_scoreboard() just
before it calls fake_working_tree_commit().

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

dir.c: ignore paths containing .git when invalidating untracked cache

read_directory() code ignores all paths named ".git" even if it's not
a valid git repository. See treat_path() for details. Since ".git" is
basically invisible to read_directory(), when we are asked to
invalidate a path that contains ".git", we can safely ignore it
because the slow path would not consider it anyway.

This helps when fsmonitor is used and we have a real ".git" repo at
worktree top. Occasionally .git/index will be updated and if the
fsmonitor hook does not filter it, untracked cache is asked to
invalidate the path ".git/index".

Without this patch, we invalidate the root directory unncessarily,
which:

- makes read_directory() fall back to slow path for root directory
(slower)

- makes the index dirty (because UNTR extension is updated). Depending
on the index size, writing it down could also be slow.

A note about the new "safe_path" knob. Since this new check could be
relatively expensive, avoid it when we know it's not needed. If the
path comes from the index, it can't contain ".git". If it does
contain, we may be screwed up at many more levels, not just this one.

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

rebase: add --allow-empty-message option

This option allows commits with empty commit messages to be rebased,
matching the same option in git-commit and git-cherry-pick. While empty
log messages are frowned upon, sometimes one finds them in older
repositories (e.g. translated from another VCS [0]), or have other
reasons for desiring them. The option is available in git-commit and
git-cherry-pick, so it is natural to make other git tools play nicely
with them. Adding this as an option allows the default to be "give the
user a chance to fix", while not interrupting the user's workflow
otherwise [1].

[0]: https://stackoverflow.com/q/8542304
[1]: https://public-inbox.org/git/7vd33afqjh.fsf@alter.siamese.dyndns.org/

To implement this, add a new --allow-empty-message flag. Then propagate
it to all calls of 'git commit', 'git cherry-pick', and 'git rebase--helper'
within the rebase scripts.

Signed-off-by: Genki Sky <sky@genki.is>
Reviewed-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

daemon: add --log-destination=(stderr|syslog|none)

This new option can be used to override the implicit --syslog of
--inetd, or to disable all logging. (While --detach also implies
--syslog, --log-destination=stderr with --detach is useless since
--detach disassociates the process from the original stderr.) --syslog
is retained as an alias for --log-destination=syslog.

--log-destination always overrides implicit --syslog regardless of
option order. This is different than the “last one wins” logic that
applies to some implicit options elsewhere in Git, but should hopefully
be less confusing. (I also don’t know if *all* implicit options in Git
follow “last one wins”.)

The combination of --inetd with --log-destination=stderr is useful, for
instance, when running `git daemon` as an instanced systemd service
(with associated socket unit). In this case, log messages sent via
syslog are received by the journal daemon, but run the risk of being
processed at a time when the `git daemon` process has already exited
(especially if the process was very short-lived, e.g. due to client
error), so that the journal daemon can no longer read its cgroup and
attach the message to the correct systemd unit (see systemd/systemd#2913
[1]). Logging to stderr instead can solve this problem, because systemd
can connect stderr directly to the journal daemon, which then already
knows which unit is associated with this stream.

[1]: https://github.com/systemd/systemd/issues/2913

Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Lucas Werkmeister <mail@lucaswerkmeister.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cocci: simplify check for trivial format strings

353d84c537 (coccicheck: make transformation for strbuf_addf(sb, "...")
more precise) added a check to avoid transforming calls with format
strings which contain percent signs, as that would change the result.
It uses embedded Python code for that. Simplify this rule by using the
regular expression matching operator instead.

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

reset --hard: make use of the pretty machinery

reset --hard currently uses its own logic for printing the first line of
the commit message in its output. Instead of just using the first line,
use the pretty machinery to create the output.

In addition to the easier to follow code, this makes the output more
consistent with other commands that print the title of the commit, such
as 'git commit --oneline' or 'git checkout', which both use
'pp_commit_easy()' with the CMIT_FMT_ONELINE modifier.

It is a slight change of the output if the second line of the commit
message is not a blank line, i.e. if the commit message is

foo
bar

previously we would print "HEAD is now at 000000 foo", while after
this change we print "HEAD is now at 000000 foo bar", same as 'git log
--oneline' shows "000000 foo bar".

So this does make the output more consistent with other commands, and
'reset' is a porcelain command, so nobody should be parsing the output
in scripts.

The current behaviour dates back to 0e5a7faa3a ("Make "git reset" a
builtin.", 2007-09-11), so I assume (without digging into the old
codebase too much) that the logic was implemented because there was
no convenience function such as 'pp_commit_easy' that would do this
already.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

perf/aggregate: sort JSON fields in output

It is much easier to diff the output against a previous
one when the fields are sorted.

Helped-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

perf/aggregate: add --reponame option

This makes it easier to use the aggregate script
on the command line when one wants to get the
"environment" fields set in the codespeed output.

Previously setting GIT_REPO_NAME was needed
for this purpose.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

perf/aggregate: add --subsection option

This makes it easier to use the aggregate script
on the command line, to get results from
subsections.

Previously setting GIT_PERF_SUBSECTION was needed
for this purpose.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

bulk-checkin: abstract SHA-1 usage

Convert uses of the direct SHA-1 functions to use the_hash_algo instead.

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

csum-file: abstract uses of SHA-1

Convert several direct uses of SHA-1 to use the_hash_algo instead.
Convert one use of the constant 20 as well.

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

csum-file: rename sha1file to hashfile

Rename struct sha1file to struct hashfile, along with all of its related
functions.

The transformation in this commit was made by global search-and-replace.

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

read-cache: abstract away uses of SHA-1

Convert various uses of direct calls to SHA-1 and 20- and 40-based
constants to use the_hash_algo instead. Don't yet convert the on-disk
data structures, which will be handled in a future commit.

Adjust some comments so as not to refer explicitly to SHA-1.

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

pack-write: switch various SHA-1 values to abstract forms

Convert various uses of hardcoded 20- and 40-based numbers to use
the_hash_algo, along with direct calls to SHA-1. Adjust the names of
variables to refer to "hash" instead of "sha1".

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

pack-check: convert various uses of SHA-1 to abstract forms

Convert various explicit calls to use SHA-1 functions and constants to
references to the_hash_algo. Make several strings more generic with
respect to the hash algorithm used.

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

fast-import: switch various uses of SHA-1 to the_hash_algo

Switch various uses of explicit calls to SHA-1 to use the_hash_algo.
Convert various uses of 20 and the GIT_SHA1 constants as well.

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

sha1_file: switch uses of SHA-1 to the_hash_algo

Switch various uses of explicit calls to SHA-1 into references to
the_hash_algo for better abstraction. Convert some calls to use struct
object_id.

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

builtin/unpack-objects: switch uses of SHA-1 to the_hash_algo

Switch various uses of explicit calls to SHA-1 into references to
the_hash_algo to better abstract away the various uses of it.

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

builtin/index-pack: improve hash function abstraction

Convert several uses of unsigned char [20] to struct object_id and
convert various hard-coded constants and uses of SHA-1 functions to use
the_hash_algo.

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

hash: create union for hash context allocation

In various parts of our code, we want to allocate a structure
representing the internal state of a hash algorithm. The original
implementation of the hash algorithm abstraction assumed we would do
that using heap allocations, and added a context size element to struct
git_hash_algo. However, most of the existing code uses stack
allocations and conversion would needlessly complicate various parts of
the code. Add a union for the purpose of allocating hash contexts on
the stack and a typedef for ease of use. Use this union for defining
the init, update, and final functions to avoid casts. Remove the ctxsz
element for struct git_hash_algo, which is no longer very useful.

This does mean that stack allocations will grow slightly as additional
hash functions are added, but this should not be a significant problem,
since we don't allocate many hash contexts. The improved usability and
benefits from avoiding dynamic allocation outweigh this small downside.

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

hash: move SHA-1 macros to hash.h

Most of the other code dealing with SHA-1 and other hashes is located in
hash.h, which is in turn loaded by cache.h. Move the SHA-1 macros to
hash.h as well, so we can use them in additional hash-related items in
the future.

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

trace: measure where the time is spent in the index-heavy operations

All the known heavy code blocks are measured (except object database
access). This should help identify if an optimization is effective or
not. An unoptimized git-status would give something like below:

0.001791141 s: read cache ...
0.004011363 s: preload index
0.000516161 s: refresh index
0.003139257 s: git command: ... 'status' '--porcelain=2'
0.006788129 s: diff-files
0.002090267 s: diff-index
0.001885735 s: initialize name hash
0.032013138 s: read directory
0.051781209 s: git command: './git' 'status'

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

gitignore.txt: elaborate shell glob syntax

`fnmatch(3)` is a great mention if the intended audience is
programmers. For normal users it's probably better to spell out what
a shell glob is.

This paragraph is updated to roughly tell (or remind) what the main
wildcards are supposed to do. All the details are still hidden away
behind the `fnmatch(3)` wall because bringing the whole specification
here may be too much.

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

format-patch: reduce patch diffstat width to 72

Patches generated by format-patch are meant to be exchanged as emails,
most of the time. And since it's generally agreed that text in mails
should be wrapped around 70 columns or so, make sure these diffstat
follow the convention (especially when used with --cover-letter since we
already defaults to wrapping 72 columns). The default can still be
overriden with command line options.

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

dir.c: stop ignoring opendir() error in open_cached_dir()

A follow-up to the recently fixed bugs in the untracked
invalidation. If opendir() fails it should show a warning, perhaps
this should die, but if this ever happens the error is probably
recoverable for the user, and dying would just make things worse.

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

wildmatch test: mark test as EXPENSIVE_ON_WINDOWS

Mark the newly added test which creates test files on-disk as
EXPENSIVE_ON_WINDOWS. According to [1] it takes almost ten minutes to
run this test file on Windows after this recent change, but just a few
seconds on Linux as noted in my [2].

This could be done faster by exiting earlier, however by using this
pattern we'll emit "skip" lines for each skipped test, making it clear
we're not running a lot of them in the TAP output, at the cost of some
overhead.

1. nycvar.QRO.7.76.6.1801061337020.1337@wbunaarf-fpuvaqryva.tvgsbejvaqbjf.bet
(https://public-inbox.org/git/nycvar.QRO.7.76.6.1801061337020.1337@wbunaarf-fpuvaqryva.tvgsbejvaqbjf.bet/)

2. 87mv1raz9p.fsf@evledraar.gmail.com
(https://public-inbox.org/git/87mv1raz9p.fsf@evledraar.gmail.com/)

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

test-lib: add an EXPENSIVE_ON_WINDOWS prerequisite

Add an EXPENSIVE_ON_WINDOWS prerequisite to mark those tests which are
very expensive to run on Windows, but cheap elsewhere.

Certain tests that heavily stress the filesystem or run a lot of shell
commands are disproportionately expensive on Windows, this
prerequisite will later be used by a tests that runs in 4-8 seconds on
a modern Linux system, but takes almost 10 minutes on Windows.

There's no reason to skip such tests by default on other platforms,
but Windows users shouldn't need to wait around while they finish.

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

wildmatch test: create & test files on disk in addition to in-memory

There has never been any full roundtrip testing of what git-ls-files
and other commands that use wildmatch() actually do, rather we've been
satisfied with just testing the underlying C function.

Due to git-ls-files and friends having their own codepaths before they
call wildmatch() there's sometimes differences in the behavior between
the two. Even when we test for those (as with [1]), there was no one
place where you can review how these two modes differ.

Now there is. We now attempt to create a file called $haystack and
match $needle against it for each pair of $needle and $haystack that
we were passing to test-wildmatch.

If we can't create the file we skip the test. This ensures that we can
run this on all platforms and not maintain some infinitely growing
whitelist of e.g. platforms that don't support certain characters in
filenames.

A notable exception to this is Windows, where due to the reasons
explained in [2] the shellscript emulation layer might fake the
creation of a file such as "*", and "test -e" for it will succeed
since it just got created with some character that maps to "*", but
git ls-files won't be fooled by this.

Thus we need to skip creating certain filenames entirely on Windows,
the list here might be overly aggressive. I don't have access to a
Windows system to test this.

As a result of doing these tests we can now see the cases where these
two ways of testing wildmatch differ:

* Creating a file called 'a[]b' and running ls-files 'a[]b' will show
that file, but wildmatch("a[]b", "a[]b") will not match

* wildmatch() won't match a file called \ against \, but ls-files
will.

* `git --glob-pathspecs ls-files 'foo**'` will match a file
'foo/bba/arr', but wildmatch won't, however pathmatch will.

This seems like a bug to me, the two are otherwise equivalent as
these tests show.

This also reveals the case discussed in [1], since 2.16.0 '' is now an
error as far as ls-files is concerned, but wildmatch() itself happily
accepts it.

1. 9e4e8a64c2 ("pathspec: die on empty strings as pathspec",
2017-06-06)

2. nycvar.QRO.7.76.6.1801052133380.1337@wbunaarf-fpuvaqryva.tvgsbejvaqbjf.bet
(https://public-inbox.org/git/?q=nycvar.QRO.7.76.6.1801052133380.1337%40wbunaarf-fpuvaqryva.tvgsbejvaqbjf.bet)

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

wildmatch test: perform all tests under all wildmatch() modes

Rewrite the wildmatch() test suite so that each test now tests all
combinations of the wildmatch() WM_CASEFOLD and WM_PATHNAME flags.

Before this change some test inputs were not tested on
e.g. WM_PATHNAME. Now the function is stress tested on all possible
inputs, and for each input we declare what the result should be if the
mode is case-insensitive, or pathname matching, or case-sensitive or
not matching pathnames.

Also before this change, nothing was testing case-insensitive
non-pathname matching, so I've added that to test-wildmatch.c and made
use of it.

This yields a rather scary patch, but there are no functional changes
here, just more test coverage. Some now-redundant tests were deleted
as a result of this change, since they were now duplicating an earlier
test.

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

wildmatch test: use test_must_fail, not ! for test-wildmatch

Use of ! should be reserved for non-git programs that are assumed not
to fail, see README. With this change only
t/t0110-urlmatch-normalization.sh is still using this anti-pattern.

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

wildmatch test: remove dead fnmatch() test code

Remove the unused fnmatch() test parameter from the wildmatch
test. The code that used to test this was removed in 70a8fc999d ("stop
using fnmatch (either native or compat)", 2014-02-15).

As a --word-diff shows the only change to the body of the tests is the
removal of the second out of four parameters passed to match().

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

wildmatch test: use a paranoia pattern from nul_match()

Use a pattern from the nul_match() function in t7008-grep-binary.sh to
make sure that we don't just fall through to the "else" if there's an
unknown parameter.

This is something I added in commit 77f6f4406f ("grep: add a test
helper function for less verbose -f \0 tests", 2017-05-20) to grep
tests, which were modeled on these wildmatch tests, and I'm now
porting back to the original wildmatch tests.

I am not using the "say '...'; exit 1" pattern from t0000-basic.sh
because if I fail I want to run the rest of the tests (unless under
-i), and doing this makes sure we do that and don't exit right away
without fully reporting our errors.

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

wildmatch test: don't try to vertically align our output

Don't try to vertically align the test output, which is futile anyway
under the TAP output where we're going to be emitting a number for
each test without aligning the test count.

This makes subsequent changes of mine where I'm not going to be
aligning this output as I add new tests easier.

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

wildmatch test: use more standard shell style

Change the wildmatch test to use more standard shell style, usually we
use "if test" not "if [".

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

wildmatch test: indent with tabs, not spaces

Replace the 4-width mixed space & tab indentation in this file with
indentation with tabs as we do in most of the rest of our tests.

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

travis-ci: don't fail if user already exists on 32 bit Linux build job

The 32 bit Linux build job runs in a Docker container, which lends
itself to running and debugging locally, too. Especially during
debugging one usually doesn't want to start with a fresh container
every time, to save time spent on installing a bunch of dependencies.
However, that doesn't work quite smootly, because the script running
in the container always creates a new user, which then must be removed
every time before subsequent executions, or the build script fails.

Make this process more convenient and don't try to create that user if
it already exists and has the right user ID in the container, so
developers don't have to bother with running a 'userdel' each time
before they run the build script.

The build job on Travis CI always starts with a fresh Docker
container, so this change doesn't make a difference there.

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

travis-ci: don't run the test suite as root in the 32 bit Linux build

Travis CI runs the 32 bit Linux build job in a Docker container, where
all commands are executed as root by default. Therefore, ever since
we added this build job in 88dedd5e7 (Travis: also test on 32-bit
Linux, 2017-03-05), we have a bit of code to create a user in the
container matching the ID of the host user and then to run the test
suite as this user. Matching the host user ID is important, because
otherwise the host user would have no access to any files written by
processes running in the container, notably the logs of failed tests
couldn't be included in the build job's trace log.

Alas, this piece of code never worked, because it sets the variable
holding the user name ($CI_USER) in a subshell, meaning it doesn't
have any effect by the time we get to the point to actually use the
variable to switch users with 'su'. So all this time we were running
the test suite as root.

Reorganize that piece of code in 'ci/run-linux32-build.sh' a bit to
avoid that problematic subshell and to ensure that we switch to the
right user. Furthermore, make the script's optional host user ID
option mandatory, so running the build accidentally as root will
become harder when debugging locally. If someone really wants to run
the test suite as root, whatever the reasons might be, it'll still be
possible to do so by explicitly passing '0' as host user ID.

Finally, one last catch: since commit 7e72cfcee (travis-ci: save prove
state for the 32 bit Linux build, 2017-12-27) the 'prove' test harness
has been writing its state to the Travis CI cache directory from
within the Docker container while running as root. After this patch
'prove' will run as a regular user, so in future build jobs it won't
be able overwrite a previously written, still root-owned state file,
resulting in build job failures. To resolve this we should manually
delete caches containing such root-owned files, but that would be a
hassle. Instead, work this around by changing the owner of the whole
contents of the cache directory to the host user ID.

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

travis-ci: don't repeat the path of the cache directory

Some of our 'ci/*' scripts repeat the name or full path of the Travis
CI cache directory, and the following patches will add new places
using that path.

Use a variable to refer to the path of the cache directory instead, so
it's hard-coded only in a single place.

Pay extra attention to the 32 bit Linux build: it runs in a Docker
container, so pass the path of the cache directory from the host to
the container in an environment variable. Note that an environment
variable passed this way is exported inside the container, therefore
its value is directly available in the 'su' snippet even though that
snippet is single quoted. Furthermore, use the variable in the
container only if it's been assigned a non-empty value, to prevent
errors when someone is running or debugging the Docker build locally,
because in that case the variable won't be set as there won't be any
Travis CI cache.

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

travis-ci: use 'set -e' in the 32 bit Linux build job

The script 'ci/run-linux32-build.sh' running inside the Docker
container of the 32 bit Linux build job uses an && chain to break the
build if one of the commands fails. This is problematic for two
reasons:

- The && chain is broken, because there is this in the middle:

test -z $HOST_UID || (CI_USER="ci" && useradd -u $HOST_UID $CI_USER) &&

Luckily it is broken in a way that it didn't lead to false
successes. If installing dependencies fails, then the rest of the
first && chain is skipped and execution resumes after the ||
operator. At that point $HOST_UID is still unset, causing
'useradd' to error out with "invalid user ID 'ci'", which in turn
causes the second && chain to abort the script and thus break the
build.

- All other 'ci/*' scripts use 'set -e' to break the build if one of
the commands fails. This inconsistency among these scripts is
asking for trouble: I forgot about the && chain more than once
while working on this patch series.

Enable 'set -e' for the whole script and for the commands executed
under 'su' as well.

While touching every line in the 'su' command block anyway, change
their indentation to use a tab instead of spaces.

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

travis-ci: use 'set -x' for the commands under 'su' in the 32 bit Linux build

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

git-svn: control destruction order to avoid segfault

It seems necessary to control destruction ordering to avoid a
segfault with SVN 1.9.5 when using "git svn branch". I've also
reported the problem against libsvn-perl to Debian [Bug #888791],
but releasing the SVN::Client instance can be beneficial anyways to
save memory.

ref: https://bugs.debian.org/888791
Tested-by: Todd Zullinger <tmz@pobox.com>
Reported-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

doc: mention 'git show' defaults to HEAD

When 'git show' is called without any object it defaults to HEAD. This
has been true since d4ed9793fd ("Simplify common default options setup
for built-in log family.", 2006-04-16).

The SYNOPSIS suggests that the object argument is required. Clarify
that it is not required and note the default.

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

sha1_file: rename hash_sha1_file_literally

This function was already converted to use struct object_id earlier.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sha1_file: convert write_loose_object to object_id

Convert the definition and declaration of static write_loose_object
function to struct object_id.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sha1_file: convert force_object_loose to object_id

Convert the definition and declaration of force_object_loose to
struct object_id and adjust usage of this function.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sha1_file: convert write_sha1_file to object_id

Convert the definition and declaration of write_sha1_file to
struct object_id and adjust usage of this function.

This commit also converts static function write_sha1_file_prepare, as it
is closely related.

Rename these functions to write_object_file and
write_object_file_prepare respectively.

Replace sha1_to_hex, hashcpy and hashclr with their oid equivalents
wherever possible.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

notes: convert write_notes_tree to object_id

Convert the definition and declaration of write_notes_tree to
struct object_id and adjust usage of this function.

Additionally, improve style of small part of this function, as old
formatting made it hard to understand at glance what this part of
code is doing.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

notes: convert combine_notes_* to object_id

Convert the definition and declarations of combine_notes_* functions
to struct object_id and adjust usage of these functions.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

commit: convert commit_tree* to object_id

Convert the definitions and declarations of commit_tree and
commit_tree_extended to use struct object_id and adjust all usages of
these functions.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

match-trees: convert splice_tree to object_id

Convert the definition of static recursive splice_tree function to use
struct object_id and adjust single caller.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache: clear whole hash buffer with oidclr

As long as GIT_SHA1_RAWSZ is equal to GIT_MAX_RAWSZ there's no problem,
but when new hashing algorithm will be in place this memset will clear
only 20-byte prefix of hash buffer.

Alternatively, hashclr implementation could be adjusted, but this
function is almost removed from codebase already. Separate
implementation of oidclr prevents potential buffer overrun in case
someone incorrectly used hashclr on object_id in future.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sha1_file: convert hash_sha1_file to object_id

Convert the declaration and definition of hash_sha1_file to use
struct object_id and adjust all function calls.

Rename this function to hash_object_file.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

dir: convert struct sha1_stat to use object_id

Convert the declaration of struct sha1_stat. Adjust all usages of this
struct and replace hash{clr,cmp,cpy} with oid{clr,cmp,cpy} wherever
possible. Rename it to struct oid_stat.

Rename static function load_sha1_stat to load_oid_stat.

Remove macro EMPTY_BLOB_SHA1_BIN, as it's no longer used.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sha1_file: convert pretend_sha1_file to object_id

Convert the declaration and definition of pretend_sha1_file to use
struct object_id and adjust all usages of this function. Rename it to
pretend_object_file.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

completion: fix completing merge strategies on non-C locales

The anchor string "Available strategies are:" is translatable so
__git_list_merge_strategies may fail to collect available strategies
from 'git merge' on non-C locales. Force C locale on this command.

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

daemon: fix length computation in newline stripping

When git-daemon gets a pktline request, we strip off any
trailing newline, replacing it with a NUL. Clients prior to
5ad312bede (in git v1.4.0) would send:

git-upload-pack repo.git\n

and we need to strip it off to understand their request.
After 5ad312bede, we send the host attribute but no newline,
like:

git-upload-pack repo.git\0host=example.com\0

Both of these are parsed correctly by git-daemon. But if
some client were to combine the two:

git-upload-pack repo.git\n\0host=example.com\0

we don't parse it correctly. The problem is that we use the
"len" variable to record the position of the NUL separator,
but then decrement it when we strip the newline. So we start
with:

git-upload-pack repo.git\n\0host=example.com\0
^-- len

and end up with:

git-upload-pack repo.git\0\0host=example.com\0
^-- len

This is arguably correct, since "len" tells us the length of
the initial string, but we don't actually use it for that.
What we do use it for is finding the offset of the extended
attributes; they used to be at len+1, but are now at len+2.

We can solve that by just leaving "len" where it is. We
don't have to care about the length of the shortened string,
since we just treat it like a C string.

No version of Git ever produced such a string, but it seems
like the daemon code meant to handle this case (and it seems
like a reasonable thing for somebody to do in a 3rd-party
implementation).

Reported-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/lib-git-daemon: add network-protocol helpers

All of our git-protocol tests rely on invoking the client
and having it make a request of a server. That gives a nice
real-world test of how the two behave together, but it
doesn't leave any room for testing how a server might react
to _other_ clients.

Let's add a few test helper functions which can be used to
manually conduct a git-protocol conversation with a remote
git-daemon:

1. To connect to a remote git-daemon, we need something
like "netcat". But not everybody will have netcat. And
even if they do, the behavior with respect to
half-duplex shutdowns is not portable (openbsd netcat
has "-N", with others you must rely on "-q 1", which is
racy).

Here we provide a "fake_nc" that is capable of doing
a client-side netcat, with sane half-duplex semantics.
It relies on perl's IO::Socket::INET. That's been in
the base distribution since 5.6.0, so it's probably
available everywhere. But just to be on the safe side,
we'll add a prereq.

2. To help tests speak and read pktline, this patch adds
packetize() and depacketize() functions.

I've put fake_nc() into lib-git-daemon.sh, since that's
really the only server where we'd need to use a network
socket. Whereas the pktline helpers may be of more general
use, so I've added them to test-lib-functions.sh. Programs
like upload-pack speak pktline, but can talk directly over
stdio without a network socket.

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

daemon: handle NULs in extended attribute string

If we receive a request with extended attributes after the
NUL, we try to write those attributes to the log. We do so
with a "%s" format specifier, which will only show
characters up to the first NUL.

That's enough for printing a "host=" specifier. But since
dfe422d04d (daemon: recognize hidden request arguments,
2017-10-16) we may have another NUL, followed by protocol
parameters, and those are not logged at all.

Let's cut out the attempt to show the whole string, and
instead log when we parse individual attributes. We could
leave the "extended attributes (%d bytes) exist" part of the
log, which in theory could alert us to attributes that fail
to parse. But anything we don't parse as a "host=" parameter
gets blindly added to the "protocol" attribute, so we'd see
it in that part of the log.

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

daemon: fix off-by-one in logging extended attributes

If receive a request like:

git-upload-pack /foo.git\0host=localhost

we mark the offset of the NUL byte as "len", and then log
the bytes after the NUL with a "%.*s" placeholder, using
"pktlen - len" as the length, and "line + len + 1" as the
start of the string.

This is off-by-one, since the start of the string skips past
the separating NUL byte, but the adjusted length includes
it. Fortunately this doesn't actually read past the end of
the buffer, since "%.*s" will stop when it hits a NUL. And
regardless of what is in the buffer, packet_read() will
always add an extra NUL terminator for safety.

As an aside, the git.git client sends an extra NUL after a
"host" field, too, so we'd generally hit that one first, not
the one added by packet_read(). You can see this in the test
output which reports 15 bytes, even though the string has
only 14 bytes of visible data. But the point is that even a
client sending unusual data could not get us to read past
the end of the buffer, so this is purely a cosmetic fix.

Reported-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/lib-git-daemon: record daemon log

When we start git-daemon for our tests, we send its stderr
log stream to a named pipe. We synchronously read the first
line to make sure that the daemon started, and then dump the
rest to descriptor 4. This is handy for debugging test
output with "--verbose", but the tests themselves can't
access the log data.

Let's dump the log into a file, as well, so that future
tests can check the log. There are a few subtleties worth
calling out here:

- we'll continue to send output to descriptor 4 for
viewing/debugging, which would imply swapping out "cat"
for "tee". But we want to ensure that there's no
buffering, and "tee" doesn't have a standard way to
ask for that. So we'll use a shell loop around "read"
and "printf" instead. That ensures that after a request
has been served, the matching log entries will have made
it to the file.

- the existing first-line shell loop used read/echo. We'll
switch to consistently using "read -r" and "printf" to
relay data as faithfully as possible.

- we open the logfile for append, rather than just output.
That makes it OK for tests to truncate the logfile
without restarting the daemon (the OS will atomically
seek to the end of the file when outputting each line).
That allows tests to look at the log without worrying
about pollution from earlier tests.

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

Docs: split out long-running subprocess handshake

Separating out the implementation of the handshake when starting a
long-running subprocess (for example, as is done for a clean/smudge
filter) was done in commit fa64a2fdbeed ("sub-process: refactor
handshake to common function", 2017-07-26), but its documentation still
resides in gitattributes. Split out the documentation as well.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/pull: respect verbosity settings in submodules

In a6d7eb2c7a (pull: optionally rebase submodules (remote submodule
changes only), 2017-06-23), we taught Git how to rebase submodules in
a pull. However we missed to pass on the verbosity settings.

Reported-by: Robin H. Johnson <robbat2@gentoo.org>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

format-patch: keep cover-letter diffstat wrapped in 72 columns

We already wrap shortlog around 72 columns in cover letters. Do the same
for diffstat (also in cover letters).

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

t5570: use ls-remote instead of clone for interp tests

We don't actually care about the clone operation here; we
just want to know if we were able to actually contact the
remote repository. Using ls-remote does that more
efficiently, and without us having to worry about managing
the tmp.git directory.

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

http-push: improve error log

When git push fails due to server-side WebDAV error, it's not easy to
point to the main culprit. Additional information about exact cURL
error and HTTP server response is helpful for debugging purpose.

New error log helped me pinpoint failing test t5540-http-push-webdav
to a missing Apache dependency in Fedora 27:
https://bugzilla.redhat.com/show_bug.cgi?id=1491151

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

clang-format: adjust penalty for return type line break

The penalty of 5 makes clang-format very eager to put even short type
declarations (e.g. "extern int") into a separate line, even when
breaking parameters list is sufficient.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

packed_ref_cache: don't use mmap() for small files

Take a hint from commit ea68b0ce9f8 (hash-object: don't use mmap() for
small files, 2010-02-21) and use read() instead of mmap() for small
packed-refs files.

Signed-off-by: Kim Gybels <kgybels@infogroep.be>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

load_contents(): don't try to mmap an empty file

We don't actually create zero-length `packed-refs` files, but they are
valid and we should handle them correctly. The old code `xmmap()`ed
such files, which led to an error when `munmap()` was called. So, if
the `packed-refs` file is empty, leave the snapshot at its zero values
and return 0 without trying to read or mmap the file.

Returning 0 also makes `create_snapshot()` exit early, which avoids
the technically undefined comparison `NULL < NULL`.

Reported-by: Kim Gybels <kgybels@infogroep.be>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

packed_ref_iterator_begin(): make optimization more general

We can return an empty iterator not only if the `packed-refs` file is
missing, but also if it is empty or if there are no references whose
names succeed `prefix`. Optimize away those cases as well by moving
the call to `find_reference_location()` higher in the function and
checking whether the determined start position is the same as
`snapshot->eof`. (This is possible now because the previous commit
made `find_reference_location()` robust against empty snapshots.)

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

find_reference_location(): make function safe for empty snapshots

This function had two problems if called for an empty snapshot (i.e.,
`snapshot->start == snapshot->eof == NULL`):

* It checked `NULL < NULL`, which is undefined by C (albeit highly
unlikely to fail in the real world).

* (Assuming the above comparison behaved as expected), it returned
NULL when `mustexist` was false, contrary to its docstring.

Change the check and fix the docstring.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

create_snapshot(): use `xmemdupz()` rather than a strbuf

It's lighter weight.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

struct snapshot: store `start` rather than `header_len`

Store a pointer to the start of the actual references within the
`packed-refs` contents rather than storing the length of the header.
This is more convenient for most users of this field.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

dir.c: fix missing dir invalidation in untracked code

Let's start with how create a new directory cache after the last one
becomes invalid (e.g. because its dir mtime has changed...). In
open_cached_dir():

1. We start out with valid_cached_dir() returning false, which should
call invalidate_directory() to put a directory state back to
initial state, no untracked entries (untracked_nr zero), no sub
directory traversal (dirs[].recurse zero).

2. Since the cache cannot be used, we go the slow path opendir() and
go through items one by one via readdir(). All the directories on
disk will be added back to the cache (if not already exist in
dirs[]) and its flag "recurse" gets changed to one to note that
it's part of the cached dir travesal next time.

3. By the time we reach close_cached_dir() we should have a good
subdir list in dirs[]. Those with "recurse" flag set are the ones
present in the on-disk directory. The directory is now marked
"valid".

Next time read_directory() is called, since the directory is marked
valid, it will skip readdir(), go fast path and traverse through
dirs[] array instead.

Steps one and two need some tight cooperation. If a subdir is removed,
readdir() will not find it and of course we cannot examine/invalidate
it. To make sure removed directories on disk are gone from the cache,
step one must make sure recurse flag of all subdirs are zero.

But that's not true. If "valid" flag is already false, there is a
chance we go straight to the end of valid_cached_dir() without calling
invalidate_directory(). Or we fail to meet the "if (untracked-valid)"
condition and skip over the invalidate_directory().

After step 3, we mark the cache valid. Any stale subdir with incorrect
recurse flag becomes a real subdir next time we traverse the directory
using dirs[] array.

We could avoid this by making sure invalidate_directory() is always
called (therefore dirs[].recurse cleared) at the beginning of
open_cached_dir(). Which is what this patch does.

As to how we get into this situation, the key in the test is this
command

git checkout master

where "one/file" is replaced with "one" in the index. This index
update triggers untracked_cache_invalidate_path(), which clears valid
flag of the root directory while keeping "recurse" flag on the subdir
"one" on. On the next git-status, we go through steps 1-3 above and
save an incorrect cache on disk. The second git-status blindly follows
the bad cache data and shows the problem.

This is arguably because of a bad design where "recurse" flag plays
double roles: whether a directory should be saved on disk, and whether
it is part of a directory traversal.

We need to keep recurse flag set at "checkout master" because of the
first role: we need to keep subdir caches (dir "two" for example has
not been touched at all, no reason to throw its cache away).

As long as we make sure to ignore/reset "recurse" flag at the
beginning of a directory traversal, we're good. But maybe eventually
we should separate these two roles.

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

dir.c: avoid stat() in valid_cached_dir()

stat() may follow a symlink and return stat data of the link's target
instead of the link itself. We are concerned about the link itself.

It's kind of hard to demonstrate the bug. I think when path->buf is a
symlink, we most likely find that its target's stat data does not
match our cached one, which means we ignore the cache and fall back to
slow path.

This is performance issue, not correctness (though we could still
catch it by verifying test-dump-untracked-cache. The less unlikely
case is, link target stat data matches the cached version and we
incorrectly go fast path, ignoring real data on disk. A test for this
may involve manipulating stat data, which may be not portable.

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

status: add a failing test showing a core.untrackedCache bug

The untracked cache gets confused when a directory is swapped out for
a file. It is easiest to reproduce this by swapping out a directory
with a symlink to another directory, and as the tests show the symlink
case is the only case we've found where "git status" will subsequently
report incorrect information, even though it's possible to otherwise
get the untracked cache into a state where its internal data
structures don't reflect reality.

In the symlink case, whatever files are inside the target of the
symlink will be incorrectly shown as untracked. This issue does not
happen if the symlink links to another file, only if it links to
another directory.

A stand-alone testcase for copying into a terminal:

(
rm -rf /tmp/testrepo &&
git init /tmp/testrepo &&
cd /tmp/testrepo &&
mkdir x y &&
touch x/a y/b &&
git add x/a y/b &&
git commit -msnap &&
git rm -rf y &&
ln -s x y &&
git add y &&
git commit -msnap2 &&
git checkout HEAD~ &&
git status &&
git checkout master &&
sleep 1 &&
git status &&
git status
)

This will incorrectly show y/a as an untracked file. Both the "git
status" call right before "git checkout master" and the "sleep 1"
after the "checkout master" are needed to reproduce this, presumably
due to the untracked cache tracking on the basis of cached whole
seconds from stat(2).

When git gets into this state, a workaround to fix it is to issue a
one-off:

git -c core.untrackedCache=false status

For the non-symlink case, the bug is that the output of
test-dump-untracked-cache should not include:

/one/ 0000000000000000000000000000000000000000 recurse valid

It being in the output implies that cached traversal of root includes
the directory "one" which does not exist on disk anymore.

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

sequencer: run 'prepare-commit-msg' hook

Commit 356ee4659b ("sequencer: try to commit without forking 'git
commit'", 2017-11-24) forgot to run the 'prepare-commit-msg' hook when
creating the commit. Fix this by writing the commit message to a
different file and running the hook. Using a different file means that
if the commit is cancelled the original message file is
unchanged. Also move the checks for an empty commit so the order
matches 'git commit'.

Reported-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t7505: add tests for cherry-pick and rebase -i/-p

Check that cherry-pick and rebase call the 'prepare-commit-msg' hook
correctly. The expected values for the hook arguments are taken to
match the current master branch. I think there is scope for improving
the arguments passed so they make a bit more sense - for instance
cherry-pick currently passes different arguments depending on whether
the commit message is being edited. Also the arguments for rebase
could be improved. Commit 7c4188360ac ("rebase -i: proper
prepare-commit-msg hook argument when squashing", 2008-10-3) apparently
changed things so that when squashing rebase would pass 'squash' as
the argument to the hook but that has been lost.

I think that it would make more sense to pass 'message' for revert and
cherry-pick -x/-s (i.e. cases where there is a new message or the
current message in modified by the command), 'squash' when squashing
with a new message and 'commit HEAD/CHERRY_PICK_HEAD'
otherwise (picking and squashing without a new message).

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t7505: style fixes

Fix the indentation and style of the hook script in preparation for
further changes.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

mailinfo: avoid segfault when can't open files

If <msg> or <patch> files can't be opened, then mailinfo() returns an
error before it even initializes mi->p_hdr_data or mi->s_hdr_data.
When cmd_mailinfo() then calls clear_mailinfo(), we dereference the
NULL pointers trying to free their contents.

Signed-off-by: Juan F. Codagnone <jcodagnone@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

read-cache: don't write index twice if we can't write shared index

In a0a967568e ("update-index --split-index: do not split if $GIT_DIR is
read only", 2014-06-13), we tried to make sure we can still write an
index, even if the shared index can not be written.

We did so by just calling 'do_write_locked_index()' just before
'write_shared_index()'. 'do_write_locked_index()' always at least
closes the tempfile nowadays, and used to close or commit the lockfile
if COMMIT_LOCK or CLOSE_LOCK were given at the time this feature was
introduced. COMMIT_LOCK or CLOSE_LOCK is passed in by most callers of
'write_locked_index()'.

After calling 'write_shared_index()', we call 'write_split_index()',
which calls 'do_write_locked_index()' again, which then tries to use the
closed lockfile again, but in fact fails to do so as it's already
closed. This eventually leads to a segfault.

Make sure to write the main index only once.

[nd: most of the commit message and investigation done by Thomas, I only
tweaked the solution a bit]

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

mru: Replace mru.[ch] with list.h implementation

Replace the custom calls to mru.[ch] with calls to list.h. This patch is
the final step in removing the mru API completely and inlining the logic.
This patch leads to significant code reduction and the mru API hence, is
not a useful abstraction anymore.

Signed-off-by: Gargi Sharma <gs051095@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

First batch after 2.16

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

Merge branch 'nd/add-i-ignore-submodules'

"git add -p" was taught to ignore local changes to submodules as
they do not interfere with the partial addition of regular changes
anyway.

* nd/add-i-ignore-submodules:
add--interactive: ignore submodule changes except HEAD

Merge branch 'mm/send-email-fallback-to-local-mail-address'

Instead of maintaining home-grown email address parsing code, ship
a copy of reasonably recent Mail::Address to be used as a fallback
in 'git send-email' when the platform lacks it.

* mm/send-email-fallback-to-local-mail-address:
send-email: add test for Linux's get_maintainer.pl
perl/Git: remove now useless email-address parsing code
send-email: add and use a local copy of Mail::Address

Merge branch 'ab/doc-cat-file-e-still-shows-errors'

Doc update.

* ab/doc-cat-file-e-still-shows-errors:
cat-file doc: document that -e will return some output

Merge branch 'as/read-tree-prefix-doc-fix'

Doc update.

* as/read-tree-prefix-doc-fix:
doc/read-tree: remove obsolete remark

Merge branch 'ys/bisect-object-id-missing-conversion-fix'

Fix for a commented-out code to adjust it to a rather old API change.

* ys/bisect-object-id-missing-conversion-fix:
bisect: debug: convert struct object to object_id

Merge branch 'tg/stash-with-pathspec-fix'

"git stash -- <pathspec>" incorrectly blew away untracked files in
the directory that matched the pathspec, which has been corrected.

* tg/stash-with-pathspec-fix:
stash: don't delete untracked files that match pathspec

Merge branch 'sb/submodule-update-reset-fix'

When resetting the working tree files recursively, the working tree
of submodules are now also reset to match.

* sb/submodule-update-reset-fix:
submodule: submodule_move_head omits old argument in forced case
unpack-trees: oneway_merge to update submodules
t/lib-submodule-update.sh: fix test ignoring ignored files in submodules
t/lib-submodule-update.sh: clarify test

Merge branch 'bw/oidmap-autoinit'

Code clean-up.

* bw/oidmap-autoinit:
oidmap: ensure map is initialized