test-oidmap: remove 'add' subcommand

The 'add' subcommand is useless as it is mostly identical
to the 'put' subcommand, so let's remove it.

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

check_everything_connected: assume alternate ref tips are valid

When we receive a remote ref update to sha1 "X", we want to check that
we have all of the objects needed by "X". We can assume that our
repository is not currently corrupted, and therefore if we have a ref
pointing at "Y", we have all of its objects. So we can stop our
traversal from "X" as soon as we hit "Y".

If we make the same non-corruption assumption about any repositories we
use to store alternates, then we can also use their ref tips to shorten
the traversal.

This is especially useful when cloning with "--reference", as we
otherwise do not have any local refs to check against, and have to
traverse the whole history, even though the other side may have sent us
few or no objects. Here are results for the included perf test (which
shows off more or less the maximal savings, getting one new commit and
sharing the whole history):

Test HEAD^ HEAD
--------------------------------------------------------------------
[on git.git]
5600.3: clone --reference 2.94(2.86+0.08) 0.09(0.08+0.01) -96.9%
[on linux.git]
5600.3: clone --reference 45.74(45.34+0.41) 0.36(0.30+0.08) -99.2%

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

object-store.h: move for_each_alternate_ref() from transport.h

There's nothing inherently transport-related about enumerating the
alternate ref tips. The code has lived in transport.[ch] because the
only use so far had been advertising available tips during transport.
But it could be used for more, and a future patch will teach rev-list to
access these refs.

Let's move it alongside the other alt-odb code, declaring it in
object-store.h with the implementation in sha1-file.c.

This lets us drop the inclusion of transport.h from receive-pack, which
perhaps shows how it was misplaced (though receive-pack is about
transporting objects, transport.h is mostly about the client side).

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

rebase --am: ignore rebase.rescheduleFailedExec

The `exec` command is specific to the interactive backend, therefore it
does not make sense for non-interactive rebases to heed that config
setting.

We still want to error out if a non-interactive rebase is started with
`--reschedule-failed-exec`, of course.

Reported by Vas Sudanagunta via:
https://github.com/git/git/commit/969de3ff0e0#commitcomment-33257187

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

blame: drop some unused function parameters

These unused parameters were introduced recently as part of the
br/blame-ignore topic. I assume they are not indicative of bugs, but are
just leftovers from the development process (they were introduced by the
series but not used in any of its iterations).

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

t7814: do not generate same commits in different repos

t7814 has repo tree like this

initial-repo
submodule
sub

In each repo 'submodule' and 'sub', a commit is made to add the same
initial file 'a' with the same message 'add a'. If tests run fast
enough, the two commits are made in the same second, resulting
identical commits.

There is nothing wrong with that per-se. But it could make the test
flaky. Currently all submodule odbs are merged back in the main
one (because we can't, or couldn't, access separate submodule repos
otherwise). But eventually we need to access objects from the right
repo.

Because the same commit could sometimes be present in both 'submodule'
and 'sub', if there is a bug looking up objects in the wrong repo,
sometimes it will go unnoticed because it finds the needed object in the
wrong repo anyway.

Fix this by changing commit time after every commit. This makes all
commits unique. Of course there are still identical blobs in different
repos, but because we often lookup commit first, then tree and blob,
unique commits are already quite safe.

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

ref-filter.c: find disjoint pattern prefixes

Since cfe004a5a9 (ref-filter: limit traversal to prefix, 2017-05-22),
the ref-filter code has sought to limit the traversals to a prefix of
the given patterns.

That code stopped short of handling more than one pattern, because it
means invoking 'for_each_ref_in' multiple times. If we're not careful
about which patterns overlap, we will output the same refs multiple
times.

For instance, consider the set of patterns 'refs/heads/a/*',
'refs/heads/a/b/c', and 'refs/tags/v1.0.0'. If we naïvely ran:

for_each_ref_in("refs/heads/a/*", ...);
for_each_ref_in("refs/heads/a/b/c", ...);
for_each_ref_in("refs/tags/v1.0.0", ...);

we would see 'refs/heads/a/b/c' (and everything underneath it) twice.

Instead, we want to partition the patterns into disjoint sets, where we
know that no ref will be matched by any two patterns in different sets.
In the above, these are:

- {'refs/heads/a/*', 'refs/heads/a/b/c'}, and
- {'refs/tags/v1.0.0'}

Given one of these disjoint sets, what is a suitable pattern to pass to
'for_each_ref_in'? One approach is to compute the longest common prefix
over all elements in that disjoint set, and let the caller cull out the
refs they didn't want. Computing the longest prefix means that in most
cases, we won't match too many things the caller would like to ignore.

The longest common prefixes of the above are:

- {'refs/heads/a/*', 'refs/heads/a/b/c'} -> refs/heads/a/*
- {'refs/tags/v1.0.0'} -> refs/tags/v1.0.0

We instead invoke:

for_each_ref_in("refs/heads/a/*", ...);
for_each_ref_in("refs/tags/v1.0.0", ...);

Which provides us with the refs we were looking for with a minimal
amount of extra cruft, but never a duplicate of the ref we asked for.

Implemented here is an algorithm which accomplishes the above, which
works as follows:

1. Lexicographically sort the given list of patterns.

2. Initialize 'prefix' to the empty string, where our goal is to
build each element in the above set of longest common prefixes.

3. Consider each pattern in the given set, and emit 'prefix' if it
reaches the end of a pattern, or touches a wildcard character. The
end of a string is treated as if it precedes a wildcard. (Note that
there is some room for future work to detect that, e.g., 'a?b' and
'abc' are disjoint).

4. Otherwise, recurse on step (3) with the slice of the list
corresponding to our current prefix (i.e., the subset of patterns
that have our prefix as a literal string prefix.)

This algorithm is 'O(kn + n log(n))', where 'k' is max(len(pattern)) for
each pattern in the list, and 'n' is len(patterns).

By discovering this set of interesting patterns, we reduce the runtime
of multi-pattern 'git for-each-ref' (and other ref traversals) from
O(N) to O(n log(N)), where 'N' is the total number of packed references.

Running 'git for-each-ref refs/tags/a refs/tags/b' on a repository with
10,000,000 refs in 'refs/tags/huge-N', my best-of-five times drop from:

real 0m5.805s
user 0m5.188s
sys 0m0.468s

to:

real 0m0.001s
user 0m0.000s
sys 0m0.000s

On linux.git, the times to dig out two of the latest -rc tags drops from
0.002s to 0.001s, so the change on repositories with fewer tags is much
less noticeable.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

progress: use term_clear_line()

To make sure that the previously displayed progress line is completely
covered up when the new line is shorter, commit 545dc345eb (progress:
break too long progress bar lines, 2019-04-12) added a bunch of
calculations to figure out how many characters it needs to overwrite
with spaces.

Use the just introduced term_clear_line() helper function to, well,
clear the last line, making all these calculations unnecessary, and
thus simplifying the code considerably.

Three tests in 't5541-http-push-smart.sh' 'grep' for specific text
shown in the progress lines at the beginning of the line, but now
those lines begin either with the ANSI escape sequence or with the
terminal width worth of space characters clearing the line. Relax the
'grep' patterns to match anywhere on the line. Note that only two of
these three tests fail without relaxing their 'grep' pattern, but the
third looks for the absence of the pattern, so it still succeeds, but
without the adjustment would potentially hide future regressions.

Note also that with this change we no longer need the length of the
previously displayed progress line, so the strbuf added to 'struct
progress' in d53ba841d4 (progress: assemble percentage and counters in
a strbuf before printing, 2019-04-05) is not strictly necessary
anymore. We still keep it, though, as it avoids allocating and
releasing a strbuf each time the progress is updated.

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

rebase: fix garbled progress display with '-x'

When running a command with the 'exec' instruction during an
interactive rebase session, or for a range of commits using 'git
rebase -x', the output can be a bit garbled when the name of the
command is short enough:

$ git rebase -x true HEAD~5
Executing: true
Executing: true
Executing: true
Executing: true
Executing: true)
Successfully rebased and updated refs/heads/master.

Note the ')' at the end of the last line. It gets more garbled as the
range of commits increases:

$ git rebase -x true HEAD~50
Executing: true)
[ repeated 3 more times ]
Executing: true0)
[ repeated 44 more times ]
Executing: true00)
Successfully rebased and updated refs/heads/master.

Those extra numbers and ')' are remnants of the previously displayed
"Rebasing (N/M)" progress lines that are usually completely
overwritten by the "Executing: <cmd>" lines, unless 'cmd' is short and
the "N/M" part is long.

Make sure that the previously displayed "Rebasing (N/M)" line is
cleared by using the term_clear_line() helper function added in the
previous patch. Do so only when not being '--verbose', because in
that case these "Rebasing (N/M)" lines are not printed as progress
(i.e. as lines with '\r' at the end), but as "regular" output (with
'\n' at the end).

A couple of other rebase commands print similar messages, e.g.
"Stopped at <abbrev-oid>... <subject>" for the 'edit' or 'break'
commands, or the "Successfully rebased and updated <full-ref>." at the
very end. These are so long that they practically always overwrite
that "Rebasing (N/M)" progress line, but let's be prudent, and clear
the last line before printing these, too.

In 't3420-rebase-autostash.sh' two helper functions prepare the
expected output of four tests that check the full output of 'git
rebase' and thus are affected by this change, so adjust their
expectations to account for the new line clearing.

Note that this patch doesn't completely eliminate the possibility of
similar garbled outputs, e.g. some error messages from rebase or the
"Auto-merging <file>" message from within the depths of the merge
machinery might not be long enough to completely cover the last
"Rebasing (N/M)" line. This patch doesn't do anything about them,
because dealing with them individually would result in way too much
churn, while having a catch-all term_clear_line() call in the common
code path of pick_commits() would hide the "Rebasing (N/M)" line way
too soon, and it would either flicker or be invisible.

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

mingw: use Unicode functions explicitly

Many Win32 API functions actually exist in two variants: one with
the `A` suffix that takes ANSI parameters (`char *` or `const char *`)
and one with the `W` suffix that takes Unicode parameters (`wchar_t *`
or `const wchar_t *`).

The ANSI variant assumes that the strings are encoded according to
whatever is the current locale. This is not what Git wants to use on
Windows: we assume that `char *` variables point to strings encoded in
UTF-8.

There is a pseudo UTF-8 locale on Windows, but it does not work
as one might expect. In addition, if we overrode the user's locale, that
would modify the behavior of programs spawned by Git (such as editors,
difftools, etc), therefore we cannot use that pseudo locale.

Further, it is actually highly encouraged to use the Unicode versions
instead of the ANSI versions, so let's do precisely that.

Note: when calling the Win32 API functions _without_ any suffix, it
depends whether the `UNICODE` constant is defined before the relevant
headers are #include'd. Without that constant, the ANSI variants are
used. Let's be explicit and avoid that ambiguity.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

mingw: get pw_name in UTF-8 format

Previously, we would have obtained the user name encoded in whatever the
current code page is.

Note: the "user name" here does not denote the full name but instead the
short logon name.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

mingw: embed a manifest to trick UAC into Doing The Right Thing

On Windows >= Vista, not having an application manifest with a
requestedExecutionLevel can cause several kinds of confusing behavior.

The first and more obvious behavior is "Installer Detection" of the
"User Account Control" (also known as "UAC") feature, where Windows
sometimes decides (by looking at things like the file name and even
sequences of bytes within the executable) that an executable is an
installer and should run elevated (causing the well-known popup dialog
to appear). In Git's context, subcommands such as "git patch-id" or "git
update-index" fall prey to this behavior.

The second and more confusing behavior is "File Virtualization". It
means that when files are written without having write permission, it
does not fail (as expected), but they are instead redirected to
somewhere else. When the files are read, the original contents are
returned, though, not the ones that were just written somewhere else.
Even more confusing, not all write accesses are redirected; Trying to
write to write-protected .exe files, for example, will fail instead of
redirecting.

In addition to being unwanted behavior, File Virtualization causes
dramatic slowdowns in Git (see for instance
http://code.google.com/p/msysgit/issues/detail?id=320).

A third unwanted behavior of Windows >= Vista is that it lies about the
Windows version when calling `GetWindowsVersionEx()`.

There are two ways to prevent these unwanted behaviors: Either you embed
an application manifest (which really is an XML document conforming to a
specific schema) within all your executables, or you add an external
manifest (a file with the same name followed by `.manifest`) to all your
executables. Since Git's builtins are hardlinked (or copied), it is
simpler and more robust to embed a manifest.

Recent enough MSVC compilers already embed a working internal manifest,
and building with mingw-w64 (which is the case in Git for Windows' SDK)
does it, too, but for MinGW you have to do so by hand.

In any case, it is better to be explicit about this manifest, that way
changes in the compiler toolchain won't surprise us (as mingw-w64 once
did when it broke `GetWindowsVersionEx()` by mistake).

References:
- New UAC Technologies for Windows Vista
http://msdn.microsoft.com/en-us/library/bb756960.aspx
- Create and Embed an Application Manifest (UAC)
http://msdn.microsoft.com/en-us/library/bb756929.aspx

Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

mingw: enable stack smashing protector

To reduce Git for Windows' attack surface, we started using the Address
Space Layout Randomization and Data Execution Prevention features in
ce6a158561f9 (mingw: enable DEP and ASLR, 2019-05-08).

To remove yet another attack vector, let's make use of gcc's stack
smashing protector that helps detect stack buffer overruns early.

Rather than using -fstack-protector, we use -fstack-protector-strong
because on Windows: The latter appears to strike a better balance
between the performance impact and the provided safety.

In a non-scientific test (time git log --grep=is -p), best of 5 timings
went from 23.009s to 22.997s, i.e. the performance impact was *well*
lost in the noise.

This fixes https://github.com/git-for-windows/git/issues/501

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Use the right 'struct repository' instead of the_repository

There are a couple of places where 'struct repository' is already passed
around, but the_repository is still used. Use the right repo.

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

match-trees.c: remove the_repo from shift_tree*()

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

tree-walk.c: remove the_repo from get_tree_entry_follow_symlinks()

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

tree-walk.c: remove the_repo from get_tree_entry()

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

tree-walk.c: remove the_repo from fill_tree_descriptor()

While at there, clean up the_repo usage in builtin/merge-tree.c a tiny
bit.

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

sha1-file.c: remove the_repo from read_object_with_reference()

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

trace2: correct typo in technical documentation

an apparent typo for the environment variable was included with 81567caf87
("trace2: update docs to describe system/global config settings",
2019-04-15), and was missed when renamed variables by e4b75d6a1d
("trace2: rename environment variables to GIT_TRACE2*", 2019-05-19)

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

status: do not report errors in sequencer/todo

commit 4a72486de9 ("fix cherry-pick/revert status after commit",
2019-04-16) used parse_insn_line() to parse the first line of the todo
list to check if it was a pick or revert. However if the todo list is
left over from an old cherry-pick or revert and references a commit that
no longer exists then parse_insn_line() prints an error message which is
confusing for users [1]. Instead parse just the command name so that the
user is alerted to the presence of stale sequencer state by status
reporting that a cherry-pick or revert is in progress.

Note that we should not be leaving stale sequencer state lying around
(or at least not as often) after commit b07d9bfd17 ("commit/reset: try
to clean up sequencer state", 2019-04-16). However the user may still
have stale state that predates that commit.

Also avoid printing an error message if for some reason the user has a
file called `sequencer` in $GIT_DIR.

[1] https://public-inbox.org/git/3bc58c33-4268-4e7c-bf1a-fe349b3cb037@www.fastmail.com/

Reported-by: Espen Antonsen <espen@inspired.no>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer: factor out todo command name parsing

Factor out the code that parses the name of the command at the start of
each line in the todo file into its own function so that it can be used
in the next commit.

As I don't want to burden other callers with having to pass in a pointer
to the end of the line the test for an abbreviated command is
changed. This change should not affect the behavior. Instead of testing
`eol == bol + 1` the new code checks for the end of the line by testing
for '\n', '\r' or '\0' following the abbreviated name. To avoid reading
past the end of an empty string it also checks that there is actually a
single character abbreviation before testing if it matches. This
prevents it from matching '\0' as the abbreviated name and then trying
to read another character.

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

sequencer: always allow tab after command name

The code that parses the todo list allows an unabbreviated command name
to be followed by a space or a tab, but if the command name is
abbreviated it only allows a space after it. Fix this inconsistency.

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

t5551: test usage of chunked encoding explicitly

When run using GIT_TEST_PROTOCOL_VERSION=2, a test in t5551 fails
because 4 POSTs (probe, ls-refs, probe, fetch) are sent instead of 2
(probe, fetch).

One way to resolve this would be to relax the condition (from "= 2" to
greater than 1, say), but upon further inspection, the test probably
shouldn't be counting the number of POSTs. This test states that large
requests are split across POSTs, but this is not correct; the main
change is that chunked transfer encoding is used, but the request is
still contained within one POST. (The test coincidentally works because
Git indeed sends 2 POSTs in the case of a large request, but that is
because, as stated above, the first POST is a probing RPC - see
post_rpc() in remote-curl.c for more information.)

Therefore, instead of counting POSTs, check that chunked transfer
encoding is used. This also has the desirable side effect of passing
with GIT_TEST_PROTOCOL_VERSION=2.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Acked-by: Derrick Stolee <dstolee@microsoft.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t5551: use 'test_i18ngrep' to check translated output

The two tests 'invalid Content-Type rejected' and 'server-side error
detected' in 't5551-http-fetch-smart.sh' use "plain" 'grep' to check
that 'git clone' failed with the expected error message, but the
messages they are checking are translated, and, consequently, these
tests fail when the test script is run with GIT_TEST_GETTEXT_POISON
enabled.

Use 'test_i18ngrep' instead.

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

submodule foreach: fix recursion of options

Calling

git submodule foreach --recursive <subcommand> --<option>

leads to an error stating that the option --<option> is unknown to
submodule--helper. That is of course only, when <option> is not a valid
option for git submodule foreach.

The reason for this is, that above call is internally translated into a
call to submodule--helper:

git submodule--helper foreach --recursive \
-- <subcommand> --<option>

This call starts by executing the subcommand with its option inside the
first level submodule and continues by calling the next iteration of
the submodule foreach call

git --super-prefix <submodulepath> submodule--helper \
foreach --recursive <subcommand> --<option>

inside the first level submodule. Note that the double dash in front of
the subcommand is missing.

This problem starts to arise only recently, as the
PARSE_OPT_KEEP_UNKNOWN flag for the argument parsing of git submodule
foreach was removed in commit a282f5a906. Hence, the unknown option is
complained about now, as the argument parsing is not properly ended by
the double dash.

This commit fixes the problem by adding the double dash in front of the
subcommand during the recursion.

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

msvc: ignore .dll and incremental compile output

Ignore .dll files copied into the top-level directory.
Ignore MSVC incremental compiler output files.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: avoid debug assertion windows in Debug Mode

For regular debugging, it is pretty helpful when a debug assertion in a
running application triggers a window that offers to start the debugger.

However, when running the test suite, it is not so helpful, in
particular when the debug assertions are then suppressed anyway because
we disable the invalid parameter checking (via invalidcontinue.obj, see
the comment in config.mak.uname about that object for more information).

So let's simply disable that window in Debug Mode (it is already
disabled in Release Mode).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: do not pretend to support all signals

This special-cases various signals that are not supported on Windows,
such as SIGPIPE. These cause the UCRT to throw asserts (at least in
debug mode).

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: add pragmas for common warnings

MSVC can be overzealous about some warnings. Disable them.

Signed-off-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: add a compile-time flag to allow detailed heap debugging

MS Visual C comes with a few neat features we can use to analyze the
heap consumption (i.e. leaks, max memory, etc).

With this patch, we introduce support via the build-time flag
`USE_MSVC_CRTDBG`.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: support building Git using MS Visual C++

With this patch, Git can be built using the Microsoft toolchain, via:

make MSVC=1 [DEBUG=1]

Third party libraries are built from source using the open source
"vcpkg" tool set. See https://github.com/Microsoft/vcpkg

On a first build, the vcpkg tools and the third party libraries are
automatically downloaded and built. DLLs for the third party libraries
are copied to the top-level (and t/helper) directory to facilitate
debugging. See compat/vcbuild/README.

A series of .bat files are invoked by the Makefile to find the location
of the installed version of Visual Studio and the associated compiler
tools (essentially replicating the environment setup performed by a
"Developer Command Prompt"). This should find the most recent VS2015 or
VS2017 installation. Output from these scripts are used by the Makefile
to define compiler and linker pathnames and -I and -L arguments.

The build produces .pdb files for both debug and release builds.

Note: This commit was squashed from an organic series of commits
developed between 2016 and 2018 in Git for Windows' `master` branch.
This combined commit eliminates the obsolete commits related to fetching
NuGet packages for third party libraries. It is difficult to use NuGet
packages for C/C++ sources because they may be built by earlier versions
of the MSVC compiler and have CRT version and linking issues.

Additionally, the C/C++ NuGet packages that we were using tended to not
be updated concurrently with the sources. And in the case of cURL and
OpenSSL, this could expose us to security issues.

Helped-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>
Helped-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pager: add a helper function to clear the last line in the terminal

There are a couple of places where we want to clear the last line on
the terminal, e.g. when a progress bar line is overwritten by a
shorter line, then the end of that progress line would remain visible,
unless we cover it up.

In 'progress.c' we did this by always appending a fixed number of
space characters to the next line (even if it was not shorter than the
previous), but as it turned out that fixed number was not quite large
enough, see the fix in 9f1fd84e15 (progress: clear previous progress
update dynamically, 2019-04-12). From then on we've been keeping
track of the length of the last displayed progress line and appending
the appropriate number of space characters to the next line, if
necessary, but, alas, this approach turned out to be error prone, see
the fix in 1aed1a5f25 (progress: avoid empty line when breaking the
progress line, 2019-05-19). The next patch in this series is about to
fix a case where we don't clear the last line, and on occasion do end
up with such garbage at the end of the line. It would be great if we
could do that without the need to deal with that without meticulously
computing the necessary number of space characters.

So add a helper function to clear the last line on the terminal using
an ANSI escape sequence, which has the advantage to clear the whole
line no matter how wide it is, even after the terminal width changed.
Such an escape sequence is not available on dumb terminals, though, so
in that case fall back to simply print a whole terminal width (as
reported by term_columns()) worth of space characters.

In 'editor.c' launch_specified_editor() already used this ANSI escape
sequence, so replace it with a call to this function.

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

t3404: make the 'rebase.missingCommitsCheck=ignore' test more focused

The test 'rebase -i respects rebase.missingCommitsCheck = warn' is
mainly interested in the warning about the dropped commits, but it
checks the whole output of 'git rebase', including progress lines and
what not that are not at all relevant to 'rebase.missingCommitsCheck',
but make it necessary to update this test whenever e.g. the way we
show progress is updated (as it will happen in one of the later
patches of this series).

Modify the test to verify only the first four lines of 'git rebase's
output that contain all the important lines, notably the line
containing the "Warning:" itself and the oneline log of the dropped
commit.

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

t3404: modernize here doc style

In 't3404-rebase-interactive.sh' the expected output of several tests
is prepared from here documents, which are outside of
'test_expect_success' blocks and have spaces around redirection
operators.

Move these here documents into the corresponding 'test_expect_success'
block and avoid spaces between filename and redition operators.
Furthermore, quote the here docs' delimiter word to prevent parameter
expansions and what not, where applicable.

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

doc: don't use git. as example gitweb URL

git.kernel.org uses cgit, not gitweb, these days:

$ w3m -dump 'http://git.kernel.org/?p=git/git.git;a=tree;f=gitweb' | grep -w generated
generated by cgit 1.2-0.3.lf.el7 (git 2.18.0) at 2019-06-22 16:14:38 +0000

Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config: simplify parsing of unit factors

Just return the value of the factor or zero for unrecognized strings
instead of using an output reference and a separate return value to
indicate success. This is shorter and simpler.

It basically reverts that function to before c8deb5a146 ("Improve error
messages when int/long cannot be parsed from config", 2007-12-25), while
keeping the better messages, so restore its old name, get_unit_factor(),
as well.

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

config: don't multiply in parse_unit_factor()

parse_unit_factor() multiplies the number that is passed to it with the
value of a recognized unit factor (K, M or G for 2^10, 2^20 and 2^30,
respectively). All callers pass in 1 as a number, though, which allows
them to check the actual multiplication for overflow before they are
doing it themselves.

Ignore the passed in number and don't multiply, as this feature of
parse_unit_factor() is not used anymore. Rename the output parameter to
reflect that it's not about the end result anymore, but just about the
unit factor.

Suggested-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config: use unsigned_mult_overflows to check for overflows

parse_unit_factor() checks if a K, M or G is present after a number and
multiplies it by 2^10, 2^20 or 2^30, respectively. One of its callers
checks if the result is smaller than the number alone to detect
overflows. The other one passes 1 as the number and does multiplication
and overflow check itself in a similar manner.

This works, but is inconsistent, and it would break if we added support
for a bigger unit factor. E.g. 16777217T is 2^64 + 2^40, i.e. too big
for a 64-bit number. Modulo 2^64 we get 2^40 == 1TB, which is bigger
than the raw number 16777217 == 2^24 + 1, so the overflow would go
undetected by that method.

Let both callers pass 1 and handle overflow check and multiplication
themselves. Do the check before the multiplication, using
unsigned_mult_overflows, which is simpler and can deal with larger unit
factors.

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

t0001: fix on case-insensitive filesystems

On a case-insensitive filesystem, such as HFS+ or NTFS, it is possible
that the idea Bash has of the current directory differs in case from
what Git thinks it is. That's totally okay, though, and we should not
expect otherwise.

On Windows, for example, when you call

cd C:\GIT-SDK-64

in a PowerShell and there exists a directory called `C:\git-sdk-64`, the
current directory will be reported in all upper-case. Even in a Bash
that you might call from that PowerShell. Git, however, will have
normalized this via `GetFinalPathByHandle()`, and the expectation in
t0001 that the recorded gitdir will match what `pwd` says will be
violated.

Let's address this by comparing these paths in a case-insensitive
manner when `core.ignoreCase` is `true`.

Reported by Jameson Miller.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

doc: improve usage string in MyFirstContribution

We implement a command called git-psuh which accept arguments, so let's
show that it accepts arguments in the doc and the usage string.

While at it, we need to prepare "a NULL-terminated array of usage strings",
not just "a NULL-terminated usage string".

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

tests: mark two failing tests under FAIL_PREREQS

Fix a couple of tests that would potentially fail under
GIT_TEST_FAIL_PREREQS=true.

I missed these when annotating other tests in dfe1a17df9 ("tests: add
a special setup where prerequisites fail", 2019-05-13) because on my
system I can only reproduce this failure when I run the tests as
"root", since the tests happen to depend on whether we can fall back
on GECOS info or not. I.e. they'd usually fail to look up the ident
info anyway, but not always.

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

The third batch

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

Merge branch 'mo/clang-format-for-each-update'

The list of for-each like macros used by clang-format has been
updated.

* mo/clang-format-for-each-update:
clang-format: use git grep to generate the ForEachMacros list

Merge branch 'md/url-parse-harden'

The URL decoding code has been updated to avoid going past the end
of the string while parsing %-<hex>-<hex> sequence.

* md/url-parse-harden:
url: do not allow %00 to represent NUL in URLs
url: do not read past end of buffer

Merge branch 'an/ignore-doc-update'

The description about slashes in gitignore patterns (used to
indicate things like "anchored to this level only" and "only
matches directories") has been revamped.

* an/ignore-doc-update:
gitignore.txt: make slash-rules more readable

Merge branch 'ab/hash-object-doc'

Doc update.

* ab/hash-object-doc:
hash-object doc: stop mentioning git-cvsimport

Merge branch 'cm/send-email-document-req-modules'

A doc update.

* cm/send-email-document-req-modules:
send-email: update documentation of required Perl modules

Merge branch 'md/list-objects-filter-parse-msgfix'

Make an end-user facing message localizable.

* md/list-objects-filter-parse-msgfix:
list-objects-filter-options: error is localizeable

Merge branch 'md/list-objects-filter-memfix'

The filter_data used in the list-objects-filter (which manages a
lazily sparse clone repository) did not use the dynamic array API
correctly---'nr' is supposed to point at one past the last element
of the array in use. This has been corrected.

* md/list-objects-filter-memfix:
list-objects-filter: correct usage of ALLOC_GROW

Merge branch 'jt/partial-clone-missing-ref-delta-base'

"git fetch" into a lazy clone forgot to fetch base objects that are
necessary to complete delta in a thin packfile, which has been
corrected.

* jt/partial-clone-missing-ref-delta-base:
t5616: cover case of client having delta base
t5616: use correct flag to check object is missing
index-pack: prefetch missing REF_DELTA bases
t5616: refactor packfile replacement

Merge branch 'ml/userdiff-rust'

The pattern "git diff/grep" use to extract funcname and words
boundary for Rust has been added.

* ml/userdiff-rust:
userdiff: two simplifications of patterns for rust
userdiff: add built-in pattern for rust

pull: add --[no-]show-forced-updates passthrough

The 'git fetch' command can avoid calculating forced updates, so
allow users of 'git pull' to provide that option. This is particularly
necessary when the advice to use '--no-show-forced-updates' is given
at the end of the command.

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

fetch: warn about forced updates in branch listing

The --[no-]show-forced-updates option in 'git fetch' can be confusing
for some users, especially if it is enabled via config setting and not
by argument. Add advice to warn the user that the (forced update)
messages were not listed.

Additionally, warn users when the forced update check takes longer
than ten seconds, and recommend that they disable the check. These
messages can be disabled by the advice.fetchShowForcedUpdates config
setting.

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

fetch: add --[no-]show-forced-updates argument

After updating a set of remove refs during a 'git fetch', we walk the
commits in the new ref value and not in the old ref value to discover
if the update was a forced update. This results in two things happening
during the command:

1. The line including the ref update has an additional "(forced-update)"
marker at the end.

2. The ref log for that remote branch includes a bit saying that update
is a forced update.

For many situations, this forced-update message happens infrequently, or
is a small bit of information among many ref updates. Many users ignore
these messages, but the calculation required here slows down their fetches
significantly. Keep in mind that they do not have the opportunity to
calculate a commit-graph file containing the newly-fetched commits, so
these comparisons can be very slow.

Add a '--[no-]show-forced-updates' option that allows a user to skip this
calculation. The only permanent result is dropping the forced-update bit
in the reflog.

Include a new fetch.showForcedUpdates config setting that allows this
behavior without including the argument in every command. The config
setting is overridden by the command-line arguments.

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

status: ignore status.aheadbehind in porcelain formats

Teach porcelain V[12] formats to ignore the status.aheadbehind
config setting. They only respect the --[no-]ahead-behind
command line argument. This is for backwards compatibility
with existing scripts.

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

status: warn when a/b calculation takes too long

The ahead/behind calculation in 'git status' can be slow in some
cases. Users may not realize that there are ways to avoid this
computation, especially if they are not using the information.

Add a warning that appears if this calculation takes more than
two seconds. The warning can be disabled through the new config
setting advice.statusAheadBehind.

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

status: add status.aheadbehind setting

The --[no-]ahead-behind option was introduced in fd9b544a
(status: add --[no-]ahead-behind to status and commit for V2
format, 2018-01-09). This is a necessary change of behavior
in repos where the remote tracking branches can move very
quickly ahead of the local branches. However, users need to
remember to provide the command-line argument every time.

Add a new "status.aheadBehind" config setting to change the
default behavior of all git status formats.

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

status: remove the empty line after hints

Before this patch, there is inconsistency between the status
messages with hints and the ones without hints: there is an
empty line between the title and the file list if hints are
presented, but there isn't one if there are no hints.

This patch remove the inconsistency by removing the empty
lines even if hints are presented.

Signed-off-by: John Lin <johnlinp@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: update Makefile to allow for spaces in the compiler path

It is quite common that MS Visual C++ is installed into a location whose
path contains spaces, therefore we need to quote it.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: fix detect_msys_tty()

The ntstatus.h header is only available in MINGW.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: define ftello()

It is just called differently in MSVC's headers.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: do not re-declare the timespec struct

VS2015's headers already declare that struct.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: mark a variable as non-const

VS2015 complains when using a const pointer in memcpy()/free().

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: define O_ACCMODE

This constant is not defined in MSVC's headers.

In UCRT's fcntl.h, _O_RDONLY, _O_WRONLY and _O_RDWR are defined as 0, 1
and 2, respectively. Yes, that means that UCRT breaks with the tradition
that O_RDWR == O_RDONLY | O_WRONLY.

It is a perfectly legal way to define those constants, though, therefore
we need to take care of defining O_ACCMODE accordingly.

This is particularly important in order to keep our "open() can set
errno to EISDIR" emulation working: it tests that (flags & O_ACCMODE) is
not identical to O_RDONLY before going on to test specifically whether
the file for which open() reported EACCES is, in fact, a directory.

Signed-off-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: include sigset_t definition

On MSVC (VS2008) sigset_t is not defined.

Signed-off-by: Philip Oakley <philipoakley@iee.org>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

msvc: fix dependencies of compat/msvc.c

The file compat/msvc.c includes compat/mingw.c, which means that we have
to recompile compat/msvc.o if compat/mingw.c changes.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

mingw: replace mingw_startup() hack

Git for Windows has special code to retrieve the command-line parameters
(and even the environment) in UTF-16 encoding, so that they can be
converted to UTF-8. This is necessary because Git for Windows wants to
use UTF-8 encoded strings throughout its code, and the main() function
does not get the parameters in that encoding.

To do that, we used the __wgetmainargs() function, which is not even a
Win32 API function, but provided by the MINGW "runtime" instead.

Obviously, this method would not work with any compiler other than GCC,
and in preparation for compiling with Visual C++, we would like to avoid
precisely that.

Lucky us, there is a much more elegant way: we can simply implement the
UTF-16 variant of `main()`: `wmain()`.

To make that work, we need to link with -municode. The command-line
parameters are passed to `wmain()` encoded in UTF-16, as desired, and
this method also works with GCC, and also with Visual C++ after
adjusting the MSVC linker flags to force it to use `wmain()`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

obstack: fix compiler warning

MS Visual C suggests that the construct

condition ? (int) i : (ptrdiff_t) d

is incorrect. Let's fix this by casting to ptrdiff_t also for the
positive arm of the conditional.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache-tree/blame: avoid reusing the DEBUG constant

In MS Visual C, the `DEBUG` constant is set automatically whenever
compiling with debug information.

This is clearly not what was intended in `cache-tree.c` nor in
`builtin/blame.c`, so let's use a less ambiguous name there.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t0001 (mingw): do not expect a specific order of stdout/stderr

When redirecting stdout/stderr to the same file, we cannot guarantee
that stdout will come first.

In fact, in this test case, it seems that an MSVC build always prints
stderr first.

In any case, this test case does not want to verify the *order* but
the *presence* of both outputs, so let's test exactly that.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Mark .bat files as requiring CR/LF endings

Just like the natural line ending for Unix shell scripts consist of a
single Line Feed, the natural line ending for (DOS) Batch scripts
consists of a Carriage Return followed by a Line Feed.

It seems that both Unix shell script interpreters and the interpreter
for Batch scripts (`cmd.exe`) are keen on seeing the "right" line
endings.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

mingw: fix a typo in the msysGit-specific section

The msysGit project (i.e. Git for Windows 1.x' SDK) is safely dead for
*years* already. This is probably the reason why nobody caught this typo
until Carlo Arenas spotted a copy-edited version of it nearby.

It is probably about time to rip out the remainders of msysGit/MSys1
support, but that can safely wait a bit longer, and we can at least fix
the typo for now.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fetch-pack: print server version at the top in -v -v

Before the previous patch, the server version is printed after all the
"Server supports" lines. The previous one puts the version in the middle
of "Server supports" group.

Instead of moving it to the bottom, I move it to the top. Version may
stand out more at the top as we will have even more debug out after
capabilities.

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

fetch-pack: print all relevant supported capabilities with -v -v

When we check if some capability is supported, we do print something in
verbose mode. Some capabilities are not printed though (and it made me
think it's not supported; I was more used to GIT_TRACE_PACKET) so let's
print them all.

It's a bit more code. And one could argue for printing all supported
capabilities the server sends us. But I think it's still valuable this
way because we see the capabilities that the client cares about.

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

fetch-pack: move capability names out of i18n strings

This reduces the work on translators since they only have one string to
translate (and I think it's still enough context to translate). It also
makes sure no capability name is translated by accident.

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

blame: add a test to cover blame_coalesce()

Signed-off-by: Barret Rhoden <brho@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

blame: use the fingerprint heuristic to match ignored lines

This commit integrates the fuzzy fingerprint heuristic into
guess_line_blames().

We actually make two passes. The first pass uses the fuzzy algorithm to
find a match within the current diff chunk. If that fails, the second
pass searches the entire parent file for the best match.

For an example of scanning the entire parent for a match, consider:

commit-a 30) #include <sys/header_a.h>
commit-b 31) #include <header_b.h>
commit-c 32) #include <header_c.h>

Then commit X alphabetizes them:

commit-X 30) #include <header_b.h>
commit-X 31) #include <header_c.h>
commit-X 32) #include <sys/header_a.h>

If we just check the parent's chunk (i.e. the first pass), we'd get:

commit-b 30) #include <header_b.h>
commit-c 31) #include <header_c.h>
commit-X 32) #include <sys/header_a.h>

That's because commit X actually consists of two chunks: one chunk is
removing sys/header_a.h, then some context, and the second chunk is
adding sys/header_a.h.

If we scan the entire parent file, we get:

commit-b 30) #include <header_b.h>
commit-c 31) #include <header_c.h>
commit-a 32) #include <sys/header_a.h>

Signed-off-by: Barret Rhoden <brho@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

blame: add a fingerprint heuristic to match ignored lines

This algorithm will replace the heuristic used to identify lines from
ignored commits with one that finds likely candidate lines in the
parent's version of the file. The actual replacement occurs in an
upcoming commit.

The old heuristic simply assigned lines in the target to the same line
number (plus offset) in the parent. The new function uses a
fingerprinting algorithm to detect similarity between lines.

The new heuristic is designed to accurately match changes made
mechanically by formatting tools such as clang-format and clang-tidy.
These tools make changes such as breaking up lines to fit within a
character limit or changing identifiers to fit with a naming convention.
The heuristic is not intended to match more extensive refactoring
changes and may give misleading results in such cases.

In most cases formatting tools preserve line ordering, so the heuristic
is optimised for such cases. (Some types of changes do reorder lines
e.g. sorting keep the line content identical, the git blame -M option
can already be used to address this). The reason that it is advantageous
to rely on ordering is due to source code repeating the same character
sequences often e.g. declaring an identifier on one line and using that
identifier on several subsequent lines. This means that lines can look
very similar to each other which presents a problem when doing fuzzy
matching. Relying on ordering gives us extra clues to point towards the
true match.

The heuristic operates on a single diff chunk change at a time. It
creates a “fingerprint” for each line on each side of the change.
Fingerprints are described in detail in the comment for `struct
fingerprint`, but essentially are a multiset of the character pairs in a
line. The heuristic first identifies the line in the target entry whose
fingerprint is most clearly matched to a line fingerprint in the parent
entry. Where fingerprints match identically, the position of the lines
is used as a tie-break. The heuristic locks in the best match, and
subtracts the fingerprint of the line in the target entry from the
fingerprint of the line in the parent entry to prevent other lines being
matched on the same parts of that line. It then repeats the process
recursively on the section of the chunk before the match, and then the
section of the chunk after the match.

Here's an example of the difference the fingerprinting makes. Consider
a file with two commits:

commit-a 1) void func_1(void *x, void *y);
commit-b 2) void func_2(void *x, void *y);

After a commit 'X', we have:

commit-X 1) void func_1(void *x,
commit-X 2) void *y);
commit-X 3) void func_2(void *x,
commit-X 4) void *y);

When we blame-ignored with the old algorithm, we get:

commit-a 1) void func_1(void *x,
commit-b 2) void *y);
commit-X 3) void func_2(void *x,
commit-X 4) void *y);

Where commit-b is blamed for 2 instead of 3. With the fingerprint
algorithm, we get:

commit-a 1) void func_1(void *x,
commit-a 2) void *y);
commit-b 3) void func_2(void *x,
commit-b 4) void *y);

Note line 2 could be matched with either commit-a or commit-b as it is
equally similar to both lines, but is matched with commit-a because its
position as a fraction of the new line range is more similar to commit-a
as a fraction of the old line range. Line 4 is also equally similar to
both lines, but as it appears after line 3 which will be matched first
it cannot be matched with an earlier line.

For many more examples, see t/t8014-blame-ignore-fuzzy.sh which contains
example parent and target files and the line numbers in the parent that
must be matched.

Signed-off-by: Michael Platings <michael@platin.gs>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

completion: disable dwim on "git switch -d"

Even though dwim is enabled by default, it will never be done when
--detached is specified. If you force "-d --guess" you will get an error
because --guess then implies -c which cannot be used with -d. So we can
disable dwim in "switch -d". It makes the completion list in this case a
bit shorter.

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

switch: allow to switch in the middle of bisect

In c45f0f525d (switch: reject if some operation is in progress,
2019-03-29), a check is added to prevent switching when some operation
is in progress. The reason is it's often not safe to do so.

This is true for merge, am, rebase, cherry-pick and revert, but not so
much for bisect because bisecting is basically jumping/switching between
a bunch of commits to pin point the first bad one. git-bisect suggests
the next commit to test, but it's not wrong for the user to test a
different commit because git-bisect cannot have the knowledge to know
better.

For this reason, allow to switch when bisecting (*). I considered if we
should still prevent switching by default and allow it with
--ignore-in-progress. But I don't think the prevention really adds
anything much.

If the user switches away by mistake, since we print the previous HEAD
value, even if they don't know about the "-" shortcut, switching back is
still possible.

The warning will be printed on every switch while bisect is still
ongoing, not the first time you switch away from bisect's suggested
commit, so it could become a bit annoying.

(*) of course when it's safe to do so, i.e. no loss of local changes and
stuff.

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

t2027: use test_must_be_empty

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

delta-islands: respect progress flag

The delta island code always prints "Marked %d islands", even if
progress has been suppressed with --no-progress or by sending stderr to
a non-tty.

Let's pass a progress boolean to load_delta_islands(). We already do
the same thing for the progress meter in resolve_tree_islands().

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

rev-list: teach --no-object-names to enable piping

Allow easier parsing by cat-file by giving rev-list an option to print
only the OID of a non-commit object without any additional information.
This is a short-term shim; later on, rev-list should be taught how to
print the types of objects it finds in a format similar to cat-file's.

Before this commit, the output from rev-list needed to be massaged
before being piped to cat-file, like so:

git rev-list --objects HEAD | cut -f 1 -d ' ' |
git cat-file --batch-check

This was especially unexpected when dealing with root trees, as an
invisible whitespace exists at the end of the OID:

git rev-list --objects --filter=tree:1 --max-count=1 HEAD |
xargs -I% echo "AA%AA"

Now, it can be piped directly, as in the added test case:

git rev-list --objects --no-object-names HEAD | git cat-file --batch-check

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Change-Id: I489bdf0a8215532e540175188883ff7541d70e1b
Signed-off-by: Junio C Hamano <gitster@pobox.com>

hashmap: convert sha1hash() to oidhash()

There are no callers left of sha1hash() that do not simply pass the
"hash" member of a "struct object_id". Let's get rid of the outdated
sha1-specific function and provide one that operates on the whole struct
(even though the technique, taking the first few bytes of the hash, will
remain the same).

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

hash.h: move object_id definition from cache.h

Our hashmap.h helpfully defines a sha1hash() function. But it cannot
define a similar oidhash() without including all of cache.h, which
itself wants to include hashmap.h! Let's break this circular dependency
by moving the definition to hash.h, along with the remaining RAWSZ
macros, etc. That will put them with the existing git_hash_algo
definition.

One alternative would be to move oidhash() into cache.h, but it's
already quite bloated. We're better off moving things out than in.

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

khash: rename oid helper functions

For use in object_id hash tables, we have oid_hash() and oid_equal().
But these are confusingly similar to the existing oideq() and the
oidhash() we plan to add to replace sha1hash().

The big difference from those functions is that rather than accepting a
const pointer to the "struct object_id", we take the arguments by value
(which is a khash internal convention). So let's make that obvious by
calling them oidhash_by_value() and oideq_by_value().

Those names are fairly horrendous to type, but we rarely need to do so;
they are passed to the khash implementation macro and then only used
internally. Callers get to use the nice kh_put_oid_map(), etc.

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

khash: drop sha1-specific map types

All of the callers of khash_sha1 and khash_sha1_pos have been removed,
in favor of using maps that use "struct object_id" as their keys. Let's
drop these now-obsolete types.

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

pack-bitmap: convert khash_sha1 maps into kh_oid_map

All of the users of our khash_sha1 maps actually have a "struct
object_id". Let's use the more descriptive type.

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

delta-islands: convert island_marks khash to use oids

All of the users of this map have an actual "struct object_id" rather
than a bare sha1. Let's use the more descriptive type (and get one step
closer to dropping khash_sha1 entirely).

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

khash: rename kh_oid_t to kh_oid_set

khash lets us define a hash as either a map or a set (i.e., with no
"value" type). For the oid maps we define, "oid" is the set and
"oid_map" is the map. As the bug in the previous commit shows, it's easy
to pick the wrong one.

So let's make the names more distinct: "oid_set" and "oid_map".

An alternative naming scheme would be to actually name the type after
the key/value types. So e.g., "oid" _would_ be the set, since it has no
value type. And "oid_map" would become "oid_void" or similar (and
"oid_pos" becomes "oid_int"). That's better in some ways: it's more
regular, and a given map type can be more reasily reused in multiple
contexts (e.g., something storing an "int" that isn't a "pos"). But it's
also slightly less descriptive.

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

khash: drop broken oid_map typedef

Commit 5a8643eff1 (khash: move oid hash table definition, 2019-02-19)
added a khash "oid_map" type to match the existing "oid" type, which is
a simple set (i.e., just keys, no values). But in setting up the
khash_oid_map typedef, it accidentally referred to "kh_oid_t", which is
the set type.

Nobody noticed the breakage because there are not yet any callers; the
type was added just as a match to the existing sha1 types (whose map
type confusingly _is_ called khash_sha1, and it has no matching set
type).

We could easily fix this with s/oid/oid_map/ in the typedef. But let's
take this a step further, and just drop the typedef entirely. These
typedefs were added by 5a8643eff1 to match the khash_sha1 typedefs. But
the actual khash-derived type names are descriptive enough; this is just
adding an extra layer of indirection. The khash names do not quite
follow our usual style (e.g., they end in "_t"), but since we end up
using other khash names (e.g., khiter_t, kh_get_oid()) anyway, just
typedef-ing the struct name is not really helping much.

And there are already many cases where we use the raw khash type names
anyway (e.g., the "set" variant defined just above us does not have such
a typedef!).

So let's drop this typedef, and the matching oid_pos one (which actually
_does_ have a user, but we can easily convert it).

We'll leave the khash_sha1 typedef around. The ultimate fate of its
callers should be conversion to kh_oid_map_t, so there's no point in
going through the noise of changing the names now.

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

object: convert create_object() to use object_id

There are no callers left of create_object() that aren't just passing us
the "hash" member of a "struct object_id". Let's take the whole struct,
which gets us closer to removing all raw sha1 variables.

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

object: convert internal hash_obj() to object_id

Now that lookup_object() has an object_id, we can consistently pass that
around instead of a raw sha1. We still convert to a hash to pass to
sha1hash(), but the goal is for that to go away shortly.

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

object: convert lookup_object() to use object_id

There are no callers left of lookup_object() that aren't just passing us
the "hash" member of a "struct object_id". Let's take the whole struct,
which gets us closer to removing all raw sha1 variables. It also
matches the existing conversions of lookup_blob(), etc.

The conversions of callers were done by hand, but they're all mechanical
one-liners.

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

object: convert lookup_unknown_object() to use object_id

There are no callers left of lookup_unknown_object() that aren't just
passing us the "hash" member of a "struct object_id". Let's take the
whole struct, which gets us closer to removing all raw sha1 variables.
It also matches the existing conversions of lookup_blob(), etc.

The conversions of callers were done by hand, but they're all mechanical
one-liners.

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

pack-objects: convert locate_object_entry_hash() to object_id

There are no callers of locate_object_entry_hash() that aren't just
passing us the "hash" member of a "struct object_id". Let's take the
whole struct, which gets us closer to removing all raw sha1 variables.

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

pack-objects: convert packlist_find() to use object_id

We take a raw hash pointer, but most of our callers have a "struct
object_id" already. Let's switch to taking the full struct, which will
let us continue removing uses of raw sha1 buffers.

There are two callers that do need special attention:

- in rebuild_existing_bitmaps(), we need to switch to
nth_packed_object_oid(). This incurs an extra hash copy over
pointing straight to the mmap'd sha1, but it shouldn't be measurable
compared to the rest of the operation.

- in can_reuse_delta() we already spent the effort to copy the sha1
into a "struct object_id", but now we just have to do so a little
earlier in the function (we can't easily convert that function's
callers because they may be pointing at mmap'd REF_DELTA blocks).

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

pack-bitmap-write: convert some helpers to use object_id

A few functions take raw hash pointers, but all of their callers
actually have a "struct object_id". Let's retain that extra type as long
as possible (which will let future patches extend that further, and so
on).

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

upload-pack: rename a "sha1" variable to "oid"

This variable is a "struct object_id", but uses the old-style name
"sha1". Let's call it oid to match more modern code (and make it clear
that it can handle any algorithm, since it uses parse_oid_hex()
properly).

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