This speeds up the tests by a bit on Windows, where running Unix shell
scripts (and spawning processes) is not exactly a cheap operation.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When building Git with RUNTIME_PREFIX and starting a test helper from
t/helper/, it fails to detect a system prefix. The reason is that the
RUNTIME_PREFIX feature wants to use the location of the Git executable
to determine where the support files can be found, e.g. system-wide Git
config or the translations. This does not make any sense for the test
helpers, though, as they are distinctly not in a directory structure
resembling the final installation location of Git.
That is the reason why the test helpers rely on environment variables to
indicate the location of the needed support files, e.g.
GIT_TEXTDOMAINDIR. If this information is missing, the output will
contain warnings like this one:
RUNTIME_PREFIX requested, but prefix computation failed. [...]
In t0061, we did not expect that to happen, and it actually does not
happen in the regular case, because bin-wrappers/test-tool specifically
sets GIT_TEXTDOMAINDIR (and as a consequence, nothing in test-tool needs
to know anything about any runtime prefix).
However, with --with-dashes, bin-wrappers/test-tool is no longer called,
but t/helper/test-tool is called directly instead.
So let's just ignore the RUNTIME_PREFIX warning.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We really need to be able to find the test helpers... Really. This
change was forgotten when we moved the test helpers into t/helper/
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It seems that every once in a while in the Git for Windows SDK, there
are some transient file locking issues preventing the test clean up to
delete the trash directory. Let's be gentle and try again five seconds
later, and only error out if it still fails the second time.
This change helps Windows, and does not hurt any other platform
(normally, it is highly unlikely that said deletion fails, and if it
does, normally it will fail again even 5 seconds later).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The JUnit XML format lends itself to be presented in a powerful UI,
where you can drill down to the information you are interested in very
quickly.
For test failures, this usually means that you want to see the detailed
trace of the failing tests.
With Travis CI, we passed the `--verbose-log` option to get those
traces. However, that seems excessive, as we do not need/use the logs in
almost all of those cases: only when a test fails do we have a way to
include the trace.
So let's do something different when using Azure DevOps: let's run all
the tests with `--quiet` first, and only if a failure is encountered,
try to trace the commands as they are executed.
Of course, we cannot turn on `--verbose-log` after the fact. So let's
just re-run the test with all the same options, adding `--verbose-log`.
And then munging the output file into the JUnit XML on the fly.
Note: there is an off chance that re-running the test in verbose mode
"fixes" the failures (and this does happen from time to time!). That is
a possibility we should be able to live with. Ideally, we would label
this as "Passed upon rerun", and Azure Pipelines even know about that
outcome, but it is not available when using the JUnit XML format for
now:
https://github.com/Microsoft/azure-pipelines-agent/blob/master/src/Agent.Worker/TestResults/JunitResultReader.cs
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is a bit ridiculous to spin up a full-blown Perl instance (especially
on Windows, where that means spinning up a full POSIX emulation layer,
AKA the MSYS2 runtime) just to tell how large a given file is.
So let's just use the test-tool to do that job instead.
This command will also be used over the next commits, to allow for
cutting out individual test cases' verbose log from the file generated
via --verbose-log.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This will come in handy when publishing the results of Git's test suite
during an automated Azure DevOps run.
Note: we need to make extra sure that invalid UTF-8 encoding is turned
into valid UTF-8 (using the Replacement Character, \uFFFD) because
t9902's trace contains such invalid byte sequences, and the task in the
Azure Pipeline that uploads the test results would refuse to do anything
if it was asked to parse an .xml file with invalid UTF-8 in it.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the next commit, we want to teach Git's test suite to optionally
output test results in JUnit-style .xml files. These files contain
information about the time spent. So we need a way to measure time.
While we could use `date +%s` for that, this will give us only seconds,
i.e. very coarse-grained timings.
GNU `date` supports `date +%s.%N` (i.e. nanosecond-precision output),
but there is no equivalent in BSD `date` (read: on macOS, we would not
be able to obtain precise timings).
So let's introduce `test-tool date getnanos`, with an optional start
time, that outputs preciser values. Note that this might not actually
give us nanosecond precision on some platforms, but it will give us as
precise information as possible, without the portability issues of shell
commands.
Granted, it is a bit pointless to try measuring times accurately in
shell scripts, certainly to nanosecond precision. But it is better than
second-granularity.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "--format=<placeholder>" option of for-each-ref, branch and tag
learned to show a few more traits of objects that can be learned by
the object_info API.
* ot/ref-filter-object-info:
ref-filter: give uintmax_t to format with %PRIuMAX
ref-filter: add docs for new options
ref-filter: add tests for deltabase
ref-filter: add deltabase option
ref-filter: add tests for objectsize:disk
ref-filter: add check for negative file size
ref-filter: add objectsize:disk option
Flaky tests can now be repeatedly run under load with the
"--stress" option.
* sg/stress-test:
test-lib: add the '--stress' option to run a test repeatedly under load
test-lib-functions: introduce the 'test_set_port' helper function
test-lib: set $TRASH_DIRECTORY earlier
test-lib: consolidate naming of test-results paths
test-lib: parse command line options earlier
test-lib: parse options in a for loop to keep $@ intact
test-lib: extract Bash version check for '-x' tracing
test-lib: translate SIGTERM and SIGHUP to an exit
An inherently racy test that caused intermittent failures has been
removed.
* tg/t5570-drop-racy-test:
Revert "t/lib-git-daemon: record daemon log"
t5570: drop racy test
"git cherry-pick -m1" was forbidden when picking a non-merge
commit, even though there _is_ parent number 1 for such a commit.
This was done to avoid mistakes back when "cherry-pick" was about
picking a single commit, but is no longer useful with "cherry-pick"
that can pick a range of commits. Now the "-m$num" option is
allowed when picking any commit, as long as $num names an existing
parent of the commit.
Technically this is a backward incompatible change; hopefully
nobody is relying on the error-checking behaviour.
* so/cherry-pick-always-allow-m1:
t3506: validate '-m 1 -ff' is now accepted for non-merge commits
t3502: validate '-m 1' argument is now accepted for non-merge commits
cherry-pick: do not error on non-merge commits when '-m 1' is specified
t3510: stop using '-m 1' to force failure mid-sequence of cherry-picks
"git worktree remove" and "git worktree move" refused to work when
there is a submodule involved. This has been loosened to ignore
uninitialized submodules.
* nd/worktree-remove-with-uninitialized-submodules:
worktree: allow to (re)move worktrees with uninitialized submodules
The test suite tried to see if it is run under bash, but the check
itself failed under some other implementations of shell (notably
under NetBSD). This has been corrected.
* sg/test-bash-version-fix:
test-lib: check Bash version for '-x' without using shell arrays
With zsh, "git cmd path<TAB>" was completed to "git cmd path name"
when the completed path has a special character like SP in it,
without any attempt to keep "path name" a single filename. This
has been fixed to complete it to "git cmd path\ name" just like
Bash completion does.
* cy/zsh-completion-SP-in-path:
completion: treat results of git ls-tree as file paths
zsh: complete unquoted paths with spaces correctly
The core.worktree setting in a submodule repository should not be
pointing at a directory when the submodule loses its working tree
(e.g. getting deinit'ed), but the code did not properly maintain
this invariant.
* sb/submodule-unset-core-worktree-when-worktree-is-lost:
submodule deinit: unset core.worktree
submodule--helper: fix BUG message in ensure_core_worktree
submodule: unset core.worktree if no working tree is present
submodule update: add regression test with old style setups
"git stripspace" should be usable outside a git repository, but
under the "-s" or "-c" mode, it didn't.
* jn/stripspace-wo-repository:
stripspace: allow -s/-c outside git repository
"git submodule update" ought to use a single job unless asked, but
by mistake used multiple jobs, which has been fixed.
* sb/submodule-fetchjobs-default-to-one:
submodule update: run at most one fetch job unless otherwise set
"git log -G<regex>" looked for a hunk in the "git log -p" patch
output that contained a string that matches the given pattern.
Optimize this code to ignore binary files, which by default will
not show any hunk that would match any pattern (unless textconv or
the --text option is in effect, that is).
* tb/log-G-binary:
log -G: ignore binary files
Lines that begin with a certain keyword that come over the wire, as
well as lines that consist only of one of these keywords, ought to
be painted in color for easier eyeballing, but the latter was
broken ever since the feature was introduced in 2.19, which has
been corrected.
* hn/highlight-sideband-keywords:
sideband: color lines with keyword only
"git checkout [<tree-ish>] path..." learned to report the number of
paths that have been checked out of the index or the tree-ish,
which gives it the same degree of noisy-ness as the case in which
the command checks out a branch.
* nd/checkout-noisy:
t0027: squelch checkout path run outside test_expect_* block
checkout: print something when checking out paths
The traversal over tree objects has learned to honor
":(attr:label)" pathspec match, which has been implemented only for
enumerating paths on the filesystem.
* nd/attr-pathspec-in-tree-walk:
tree-walk: support :(attr) matching
dir.c: move, rename and export match_attrs()
pathspec.h: clean up "extern" in function declarations
tree-walk.c: make tree_entry_interesting() take an index
tree.c: make read_tree*() take 'struct repository *'
"git rev-list --exclude-promisor-objects" had to take an object
that does not exist locally (and is lazily available) from the
command line without barfing, but the code dereferenced NULL.
* md/list-lazy-objects-fix:
list-objects.c: don't segfault for missing cmdline objects
Uninitialized submodules have nothing valueable for us to be worried
about. They are just SHA-1. Let "worktree remove" and "worktree move"
continue in this case so that people can still use multiple worktrees
on repos with optional submodules that are never populated, like
sha1collisiondetection in git.git when checked out by doc-diff script.
Note that for "worktree remove", it is possible that a user
initializes a submodule (*), makes some commits (but not push), then
deinitializes it. At that point, the submodule is unpopulated, but the
precious new commits are still in
$GIT_COMMON_DIR/worktrees/<worktree>/modules/<submodule>
directory and we should not allow removing the worktree or we lose
those commits forever. The new directory check is added to prevent
this.
(*) yes they are screwed anyway by doing this since "git submodule"
would add submodule.* in $GIT_COMMON_DIR/config, which is shared
across multiple worktrees. But it does not mean we let them be
screwed even more.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Unfortunately, we have a few flaky tests, whose failures tend to be
hard to reproduce. We've found that the best we can do to reproduce
such a failure is to run the test script repeatedly while the machine
is under load, and wait in the hope that the load creates enough
variance in the timing of the test's commands that a failure is
evenually triggered. I have a command to do that, and I noticed that
two other contributors have rolled their own scripts to do the same,
all choosing slightly different approaches.
To help reproduce failures in flaky tests, introduce the '--stress'
option to run a test script repeatedly in multiple parallel jobs until
one of them fails, thereby using the test script itself to increase
the load on the machine.
The number of parallel jobs is determined by, in order of precedence:
the number specified as '--stress=<N>', or the value of the
GIT_TEST_STRESS_LOAD environment variable, or twice the number of
available processors (as reported by the 'getconf' utility), or 8.
Make '--stress' imply '--verbose -x --immediate' to get the most
information about rare failures; there is really no point in spending
all the extra effort to reproduce such a failure, and then not know
which command failed and why.
To prevent the several parallel invocations of the same test from
interfering with each other:
- Include the parallel job's number in the name of the trash
directory and the various output files under 't/test-results/' as
a '.stress-<Nr>' suffix.
- Add the parallel job's number to the port number specified by the
user or to the test number, so even tests involving daemons
listening on a TCP socket can be stressed.
- Redirect each parallel test run's verbose output to
't/test-results/$TEST_NAME.stress-<nr>.out', because dumping the
output of several parallel running tests to the terminal would
create a big ugly mess.
For convenience, print the output of the failed test job at the end,
and rename its trash directory to end with the '.stress-failed'
suffix, so it's easy to find in a predictable path (OTOH, all absolute
paths recorded in the trash directory become invalid; we'll see
whether this causes any issues in practice). If, in an unlikely case,
more than one jobs were to fail nearly at the same time, then print
the output of all failed jobs, and rename the trash directory of only
the last one (i.e. with the highest job number), as it is the trash
directory of the test whose output will be at the bottom of the user's
terminal.
Based on Jeff King's 'stress' script.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Several test scripts run daemons like 'git-daemon' or Apache, and
communicate with them through TCP sockets. To have unique ports where
these daemons are accessible, the ports are usually the number of the
corresponding test scripts, unless the user overrides them via
environment variables, and thus all those tests and test libs contain
more or less the same bit of one-liner boilerplate code to find out
the port. The last patch in this series will make this a bit more
complicated.
Factor out finding the port for a daemon into the common helper
function 'test_set_port' to avoid repeating ourselves.
Take special care of test scripts with "low" numbers:
- Test numbers below 1024 would result in a port that's only usable
as root, so set their port to '10000 + test-nr' to make sure it
doesn't interfere with other tests in the test suite. This makes
the hardcoded port number in 't0410-partial-clone.sh' unnecessary,
remove it.
- The shell's arithmetic evaluation interprets numbers with leading
zeros as octal values, which means that test number below 1000 and
containing the digits 8 or 9 will trigger an error. Remove all
leading zeros from the test numbers to prevent this.
Note that the 'git p4' tests are unlike the other tests involving
daemons in that:
- 'lib-git-p4.sh' doesn't use the test's number for unique port as
is, but does a bit of additional arithmetic on top [1].
- The port is not overridable via an environment variable.
With this patch even 'git p4' tests will use the test's number as
default port, and it will be overridable via the P4DPORT environment
variable.
[1] Commit fc00233071 (git-p4 tests: refactor and cleanup, 2011-08-22)
introduced that "unusual" unique port computation without
explaining why it was necessary (as opposed to simply using the
test number as is). It seems to be just unnecessary complication,
and in any case that commit came way before the "test nr as unique
port" got "standardized" for other daemons in commits c44132fcf3
(tests: auto-set git-daemon port, 2014-02-10), 3bb486e439 (tests:
auto-set LIB_HTTPD_PORT from test name, 2014-02-10), and
bf9d7df950 (t/lib-git-svn.sh: improve svnserve tests with parallel
make test, 2017-12-01).
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A later patch in this series will need to know the path to the trash
directory early in 'test-lib.sh', but $TRASH_DIRECTORY is set much
later.
Set $TRASH_DIRECTORY earlier, where the other test-specific path
variables are set.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are two places where we strip off any leading path components
and the '.sh' suffix from the test script's pathname, and there are
four places where we construct the name of the 't/test-results'
directory or the name of various test-specific files in there. The
last patch in this series will add even more.
Factor these out into helper variables to avoid repeating ourselves.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
'test-lib.sh' looks for the presence of certain options like '--tee'
and '--verbose-log', so it can execute the test script again to save
its standard output and error. It looks for '--valgrind' as well, to
set up some Valgrind-specific stuff. These all happen before the
actual option parsing loop, and the conditions looking for these
options look a bit odd, too. They are not completely correct, either,
because in a bogus invocation like './t1234-foo.sh -r --tee' they
recognize '--tee', although it should be handled as the required
argument of the '-r' option. This patch series will add two more
options to look out for early, and, in addition, will have to extract
these options' stuck arguments (i.e. '--opt=arg') as well.
So let's move the option parsing loop and the couple of related
conditions following it earlier in 'test-lib.sh', before the place
where the test script is executed again for '--tee' and its friends.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
'test-lib.sh' looks for the presence of certain options like '--tee'
and '--verbose-log', so it can execute the test script again to save
its standard output and error, and to do so it needs the original
command line options the test was invoked with.
The next patch is about to move the option parsing loop earlier in
'test-lib.sh', but it is implemented using 'shift' in a while loop,
effecively destroying "$@" by the end of the option parsing. Not
good.
As a preparatory step, turn that option parsing loop into a 'for opt
in "$@"' loop to preserve "$@" intact while iterating over the
options, and taking extra care to handle the '-r' option's required
argument (or the lack thereof).
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
One of our test scripts, 't1510-repo-setup.sh' [1], still can't be
reliably run with '-x' tracing enabled, unless it's executed with a
Bash version supporting BASH_XTRACEFD (since v4.1). We have a lengthy
condition to check the version of the shell running the test script,
and disable tracing if it's not executed with a suitable Bash version
[2].
Move this check out from the option parsing loop, so other options can
imply '-x' by setting 'trace=t', without missing this Bash version
check.
[1] 5827506928 (t1510-repo-setup: mark as untraceable with '-x',
2018-02-24)
[2] 5fc98e79fc (t: add means to disable '-x' tracing for individual
test scripts, 2018-02-24)
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reverts commit 314a73d658 (t/lib-git-daemon: record daemon log,
2018-01-25), which let tests use the output of git-daemon.
The previous commit removed the last user of deamon.log in the tests,
there's no good way to make checking for output in the log
race-proof. Revert this commit as well, to make sure others are not
tempted to use daemon.log in tests in the future, which would lead to
racy tests.
The original commit had one change that still makes sense, namely
switching read/echo for "read -r" and "printf", which relays the data
more faithfully. Don't revert that piece here, as it is still a
useful change.
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A properly configured username/email is required under
user.useConfigOnly in order to create commits; now "git stash"
(even though it creates commit objects to represent stash entries)
command is exempt from the requirement.
* sd/stash-wo-user-name:
stash: tolerate missing user identity
Refspecs configured with "git -c var=val clone" did not propagate
to the resulting repository, which has been corrected.
* sg/clone-initial-fetch-configuration:
Documentation/clone: document ignored configuration variables
clone: respect additional configured fetch refspecs during initial fetch
clone: use a more appropriate variable name for the default refspec
"git checkout frotz" (without any double-dash) avoids ambiguity by
making sure 'frotz' cannot be interpreted as a revision and as a
path at the same time. This safety has been updated to check also
a unique remote-tracking branch 'frotz' in a remote, when dwimming
to create a local branch 'frotz' out of a remote-tracking branch
'frotz' from a remote.
* nd/checkout-dwim-fix:
checkout: disambiguate dwim tracking branches and local files
"git push $there $src:$dst" rejects when $dst is not a fully
qualified refname and not clear what the end user meant. The
codepath has been taught to give a clearer error message, and also
guess where the push should go by taking the type of the pushed
object into account (e.g. a tag object would want to go under
refs/tags/).
* ab/push-dwim-dst:
push doc: document the DWYM behavior pushing to unqualified <dst>
push: test that <src> doesn't DWYM if <dst> is unqualified
push: add an advice on unqualified <dst> push
push: move unqualified refname error into a function
push: improve the error shown on unqualified <dst> push
i18n: remote.c: mark error(...) messages for translation
remote.c: add braces in anticipation of a follow-up change
Small fixes and features for fast-export and fast-import, mostly on
the fast-export side.
* en/fast-export-import:
fast-export: add a --show-original-ids option to show original names
fast-import: remove unmaintained duplicate documentation
fast-export: add --reference-excluded-parents option
fast-export: ensure we export requested refs
fast-export: when using paths, avoid corrupt stream with non-existent mark
fast-export: move commit rewriting logic into a function for reuse
fast-export: avoid dying when filtering by paths and old tags exist
fast-export: use value from correct enum
git-fast-export.txt: clarify misleading documentation about rev-list args
git-fast-import.txt: fix documentation for --quiet option
fast-export: convert sha1 to oid
More _("i18n") markings.
* nd/i18n:
fsck: mark strings for translation
fsck: reduce word legos to help i18n
parse-options.c: mark more strings for translation
parse-options.c: turn some die() to BUG()
parse-options: replace opterror() with optname()
repack: mark more strings for translation
remote.c: mark messages for translation
remote.c: turn some error() or die() to BUG()
reflog: mark strings for translation
read-cache.c: add missing colon separators
read-cache.c: mark more strings for translation
read-cache.c: turn die("internal error") to BUG()
attr.c: mark more string for translation
archive.c: mark more strings for translation
alias.c: mark split_cmdline_strerror() strings for translation
git.c: mark more strings for translation
Right now if a test script receives SIGTERM or SIGHUP (e.g., because a
test was hanging and the user 'kill'-ed it or simply closed the
terminal window the test was running in), the shell exits immediately.
This can be annoying if the test script did any global setup, like
starting apache or git-daemon, as it will not have an opportunity to
clean up after itself. A subsequent run of the test won't be able to
start its own daemon, and will either fail or skip the tests.
Instead, let's trap SIGTERM and SIGHUP as well to make sure we do a
clean shutdown, and just chain it to a normal exit (which will trigger
any cleanup).
This patch follows suit of da706545f7 (t: translate SIGINT to an exit,
2015-03-13), and even stole its commit message as well.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
One of our test scripts, 't1510-repo-setup.sh' [1], still can't be
reliably run with '-x' tracing enabled, unless it's executed with a
Bash version supporting BASH_XTRACEFD (since v4.1). We have a lengthy
condition to check the version of the shell running the test script,
and disable tracing if it's not executed with a suitable Bash version
[2].
This condition uses non-portable shell array accesses to easily get
Bash's major and minor version number. This didn't seem to be
problematic, because the simple commands expanding those array
accesses are only executed when the test script is actually run with
Bash. When run with Dash, the only shell I have at hand that doesn't
support shell arrays, there are no issues, as it apparently skips
right over the non-executed simple commands without noticing the
non-supported constructs.
Alas, it has been reported that NetBSD's /bin/sh does complain about
them:
./test-lib.sh: 327: Syntax error: Bad substitution
where line 327 contains the first ${BASH_VERSINFO[0]} array access.
To my understanding both shells are right and conform to POSIX,
because the standard allows both behaviors by stating the following
under '2.8.1 Consequences of Shell Errors' [3]:
"An expansion error is one that occurs when the shell expansions
define in wordexp are carried out (for example, "${x!y}", because
'!' is not a valid operator); an implementation may treat these as
syntax errors if it is able to detect them during tokenization,
rather than during expansion."
Avoid this issue with NetBSD's /bin/sh (and potentially with other,
less common shells) by hiding the shell array syntax behind 'eval'
that is only executed with Bash.
[1] 5827506928 (t1510-repo-setup: mark as untraceable with '-x',
2018-02-24)
[2] 5fc98e79fc (t: add means to disable '-x' tracing for individual
test scripts, 2018-02-24)
[3] http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_08_01
Reported-by: Max Kirillov <max@max630.net>
Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
