color: introduce support for colorizing stderr

So far, we only ever asked whether stdout wants to be colorful. In the
upcoming patches, we will want to make push errors more prominent, which
are printed to stderr, though.

So let's refactor the want_color() function into a want_color_fd()
function (which expects to be called with fd == 1 or fd == 2 for stdout
and stderr, respectively), and then define the macro `want_color()` to
use the want_color_fd() function.

And then also add a macro `want_color_stderr()`, for convenience and
for documentation.

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

builtin/config: introduce `color` type specifier

As of this commit, the canonical way to retreive an ANSI-compatible
color escape sequence from a configuration file is with the
`--get-color` action.

This is to allow Git to "fall back" on a default value for the color
should the given section not exist in the specified configuration(s).

With the addition of `--default`, this is no longer needed since:

$ git config --default red --type=color core.section

will be have exactly as:

$ git config --get-color core.section red

For consistency, let's introduce `--type=color` and encourage its use
with `--default` together over `--get-color` alone.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config.c: introduce 'git_config_color' to parse ANSI colors

In preparation for adding `--type=color` to the `git-config(1)` builtin,
let's introduce a color parsing utility, `git_config_color` in a similar
fashion to `git_config_<type>`.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/config: introduce `--default`

For some use cases, callers of the `git-config(1)` builtin would like to
fallback to default values when the variable asked for does not exist.
In addition, users would like to use existing type specifiers to ensure
that values are parsed correctly when they do exist in the
configuration.

For example, to fetch a value without a type specifier and fallback to
`$fallback`, the following is required:

$ git config core.foo || echo "$fallback"

This is fine for most values, but can be tricky for difficult-to-express
`$fallback`'s, like ANSI color codes.

This motivates `--get-color`, which is a one-off exception to the normal
type specifier rules wherein a user specifies both the configuration
variable and an optional fallback. Both are formatted according to their
type specifier, which eases the burden on the user to ensure that values
are correctly formatted.

This commit (and those following it in this series) aim to eventually
replace `--get-color` with a consistent alternative. By introducing
`--default`, we allow the `--get-color` action to be promoted to a
`--type=color` type specifier, retaining the "fallback" behavior via the
`--default` flag introduced in this commit.

For example, we aim to replace:

$ git config --get-color variable [default] [...]

with:

$ git config --default default --type=color variable [...]

Values filled by `--default` behave exactly as if they were present in
the affected configuration file; they will be parsed by type specifiers
without the knowledge that they are not themselves present in the
configuration.

Specifically, this means that the following will work:

$ git config --int --default 1M does.not.exist
1048576

In subsequent commits, we will offer `--type=color`, which (in
conjunction with `--default`) will be sufficient to replace
`--get-color`.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

parseopt: handle malformed --expire arguments more nicely

A few commands that parse --expire=<time> command line option behave
sillily when given nonsense input. For example

$ git prune --no-expire
Segmentation falut
$ git prune --expire=npw; echo $?
129

Both come from parse_opt_expiry_date_cb().

The former is because the function is not prepared to see arg==NULL
(for "--no-expire", it is a norm; "--expire" at the end of the
command line could be made to pass NULL, if it is told that the
argument is optional, but we don't so we do not have to worry about
that case).

The latter is because it does not check the value returned from the
underlying parse_expiry_date().

This seems to be a recent regression introduced while we attempted
to avoid spewing the entire usage message when given a correct
option but with an invalid value at 3bb0923f ("parse-options: do not
show usage upon invalid option value", 2018-03-22). Before that, we
didn't fail silently but showed a full usage help (which arguably is
not all that better).

Also catch this error early when "git gc --prune=<expiration>" is
misspelled by doing a dummy parsing before the main body of "gc"
that is time consuming even begins. Otherwise, we'd spend time to
pack objects and then later have "git prune" first notice the error.
Aborting "gc" in the middle that way is not harmful but is ugly and
can be avoided.

Helped-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gc: do not upcase error message shown with die()

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

fast-export: fix regression skipping some merge-commits

7199203937 (object_array: add and use `object_array_pop()`, 2017-09-23)
noted that the pattern `object = array.objects[--array.nr].item` could
be abstracted as `object = object_array_pop(&array)`.

Unfortunately, one of the conversions was horribly wrong. Between
grabbing the last object (i.e., peeking at it) and decreasing the object
count, the original code would sometimes return early. The updated code
on the other hand, will always pop the last element, then maybe do the
early return without doing anything with the object.

The end result is that merge commits where all the parents have still
not been exported will simply be dropped, meaning that they will be
completely missing from the exported data.

Re-add a commit when it is not yet time to handle it. An alternative
that was considered was to peek-then-pop. That carries some risk with it
since the peeking and popping need to act on the same object, in a
concerted fashion.

Add a test that would have caught this.

Reported-by: Isaac Chou <Isaac.Chou@microfocus.com>
Analyzed-by: Isaac Chou <Isaac.Chou@microfocus.com>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

completion: make stash -p and alias for stash push -p

We define 'git stash -p' as an alias for 'git stash push -p' in the
manpage. Do the same in the completion script, so all options that
can be given to 'git stash push' are being completed when the user is
using 'git stash -p --<tab>'. Currently the only additional option
the user will get is '--message', but there may be more in the future.

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

completion: stop showing 'save' for stash by default

The 'save' subcommand in git stash has been deprecated in
fd2ebf14db ("stash: mark "git stash save" deprecated in the man page",
2017-10-22).

Stop showing it when the users enters 'git stash <tab>' or 'git stash
s<tab>'. Keep showing it however when the user enters 'git stash sa<tab>'
or any more characters of the 'save' subcommand. This is designed to
not encourage users to use 'git stash save', but still leaving the
completion option once it's clear that's what the user means.

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

doc/clone: update caption for GIT URLS cross-reference

The description of the <repository> argument directs readers to "See the
URLS section below". When generating HTML this becomes a link to the
"GIT URLS" section. When reading the man page in a terminal, the
caption is slightly misleading. Use "GIT URLS" as the caption to avoid
any confusion.

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

builtin/config.c: support `--type=<type>` as preferred alias for `--<type>`

`git config` has long allowed the ability for callers to provide a 'type
specifier', which instructs `git config` to (1) ensure that incoming
values can be interpreted as that type, and (2) that outgoing values are
canonicalized under that type.

In another series, we propose to extend this functionality with
`--type=color` and `--default` to replace `--get-color`.

However, we traditionally use `--color` to mean "colorize this output",
instead of "this value should be treated as a color".

Currently, `git config` does not support this kind of colorization, but
we should be careful to avoid squatting on this option too soon, so that
`git config` can support `--color` (in the traditional sense) in the
future, if that is desired.

In this patch, we support `--type=<int|bool|bool-or-int|...>` in
addition to `--int`, `--bool`, and etc. This allows the aforementioned
upcoming patch to support querying a color value with a default via
`--type=color --default=...`, without squandering `--color`.

We retain the historic behavior of complaining when multiple,
legacy-style `--<type>` flags are given, as well as extend this to
conflicting new-style `--type=<type>` flags. `--int --type=int` (and its
commutative pair) does not complain, but `--bool --type=int` (and its
commutative pair) does.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer: reset the committer date before commits

Now that the sequencer commits without forking when the commit message
isn't edited all the commits that are picked have the same committer
date. If a commit is reworded it's committer date will be a later time
as it is created by running an separate instance of 'git commit'. If
the reworded commit is follow by further picks, those later commits
will have an earlier committer date than the reworded one. This is
caused by git caching the default date used when GIT_COMMITTER_DATE is
not set. Reset the cached date before a commit is generated
in-process.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

send-email: avoid duplicate In-Reply-To/References

In case a patch already has In-Reply-To or References in the header
(e.g. when the patch has been created with format-patch --thread)
git-send-email should not add another pair of those headers.
This is also not allowed according to RFC 5322 Section 3.6:
https://tools.ietf.org/html/rfc5322#section-3.6

Avoid the second pair by reading the current headers into the
appropriate variables.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile: mark perllibdir as a .PHONY target

This target should be marked as .PHONY, just like other targets that
exist only for their side effects that do not create filesystem
entities with the same name.

Signed-off-by: Christian Hesse <mail@eworm.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

submodule--helper: don't print null in 'submodule status'

The function compute_rev_name() can return NULL sometimes (e.g. right
after 'submodule init'). The current code makes 'submodule status'
print this:

19d97bf5af05312267c2e874ee6bcf584d9e9681 sha1collisiondetection ((null))

This ugly 'null' adds no value to the user using this command. More
importantly printf() on some platform can't handle NULL as a string
and will crash instead of printing '(null)'.

Check for this and skip printing this part (the alternative is
printing '(n/a)' or something but I think that is just noise).

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

git-submodule.txt: quote usage in monospace, drop backslash

We tend to quote command line examples using `` to set them in a
monospace font. The immediate motivation for this patch is to get rid of
another instance of \--. As noted in the previous commits, \-- has a
tendency of rendering badly. Here, it renders ok (at least with
AsciiDoc 8.6.9 and Asciidoctor 1.5.4), but by getting rid of this
instance, we reduce the chances of \-- cropping up in places where it
matters more.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>

git-[short]log.txt: unify quoted standalone --

In git-log.txt, we have an instance of \--, which is known to sometimes
render badly. This one is even worse than normal though, since ``\-- ''
(with or without that trailing space) appears to be entirely broken,
both in HTML and manpages, both with AsciiDoc (version 8.6.9) and
Asciidoctor (version 1.5.4).

Further down in git-log.txt we have a ``--'', which renders good. In
git-shortlog.txt, we use "\-- " (including the quotes and the space),
which happens to look fairly good. I failed to find any other similar
instances. So all in all, we quote a double-dash in three different
places and do it differently each time, with various degrees of success.

Switch all of these to `--`. This sets the double-dash in monospace and
matches what we usually do with example command line usages and options.
Note that we drop the trailing space as well, since `-- ` does not
render well. These should still be clear enough since just a few lines
above each instance, the space is clearly visible in a longer context.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>

doc: convert [\--] to [--]

Commit 1c262bb7b (doc: convert \--option to --option, 2015-05-13)
explains that we used to need to write \--option to play well with older
versions of AsciiDoc, but that we do not support such versions anymore
anyway, and that Asciidoctor literally renders \--.

With [\--], which is used to denote the optional separator between
revisions and paths, Asciidoctor renders the backslash literally.
Change all [\--] to [--]. This changes nothing for AsciiDoc version
8.6.9, but is an improvement for Asciidoctor version 1.5.4.

We use double-dashes in several list entries (\--::). In my testing, it
appears that we do need to use the backslash there, so leave those.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>

doc: convert \--option to --option

Rather than using a backslash in \--foo, with or without ''-quoting,
write `--foo` for better rendering. As explained in commit 1c262bb7b
(doc: convert \--option to --option, 2015-05-13), the backslash is not
needed for the versions of AsciiDoc that we support, but is rendered
literally by Asciidoctor.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>

docs/git-gc: fix minor rendering issue

An unwanted single quote character in the paragraph documenting the
'gc.aggressiveWindow' config variable prevented the name of that
config variable from being rendered correctly, ever since that piece
of docs was added in 0d7566a5ba (Add --aggressive option to 'git gc',
2007-05-09).

Remove that single quote.

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

worktree: accept -f as short for --force for removal

Many commands support a "--force" option, frequently abbreviated as
"-f", however, "git worktree remove"'s hand-rolled OPT_BOOL forgets
to recognize the short form, despite git-worktree.txt documenting
"-f" as supported. Replace OPT_BOOL with OPT__FORCE, which provides
"-f" for free, and makes 'remove' consistent with 'add' option
parsing (which also specifies the PARSE_OPT_NOCOMPLETE flag).

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

completion: reduce overhead of clearing cached --options

To get the names of all '$__git_builtin_*' variables caching --options
of builtin commands in order to unset them, 8b0eaa41f2 (completion:
clear cached --options when sourcing the completion script,
2018-03-22) runs a 'set |sed s///' pipeline. This works both in Bash
and in ZSH, but has a higher than necessary overhead with the extra
processes.

In Bash we can do better: run the 'compgen -v __gitcomp_builtin_'
builtin command, which lists the same variables, but without a
pipeline and 'sed' it can do so with lower overhead.
ZSH will still continue to run that pipeline.

This change also happens to work around an issue in the default Bash
version shipped in macOS (3.2.57), reported by users of the Powerline
shell prompt, which was triggered by the same commit 8b0eaa41f2 as
well. Powerline uses several Unicode Private Use Area code points to
represent some of its pretty text UI elements (arrows and what not),
and these are stored in the $PS1 variable. Apparently the 'set'
builtin of said Bash version on macOS has issues with these code
points, and produces garbled output where Powerline's special symbols
should be in the $PS1 variable. This, in turn, triggers the following
error message in the downstream 'sed' process:

sed: RE error: illegal byte sequence

Other Bash versions, notably 4.4.19 on macOS via homebrew (i.e. a
newer version on the same platform) and 3.2.25 on CentOS (i.e. a
slightly earlier version, though on a different platform) are not
affected. ZSH in macOS (the versions shipped by default or installed
via homebrew) or on other platforms isn't affected either.

With this patch neither the 'set' builtin is invoked to print garbage,
nor 'sed' to choke on it.

Issue-on-macOS-reported-by: Stephon Harris <theonestep4@gmail.com>
Issue-on-macOS-explained-by: Matthew Coleman <matt@1eanda.com>
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

glossary: substitute "ancestor" for "direct ancestor" in 'push' description.

Even though "direct ancestor" is not defined in the glossary, the
common meaning of the term is simply "parent", parents being the only
direct ancestors, and the rest of ancestors being indirect ancestors.

As "parent" is obviously wrong in this place in the description, we
should simply say "ancestor", as everywhere else.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t1510-repo-setup.sh: remove useless mkdir

Signed-off-by: Tao Qingyun <845767657@qq.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git{,-blame}.el: remove old bitrotting Emacs code

The git-blame.el mode has been superseded by Emacs's own
vc-annotate (invoked by C-x v g). Users of the git.el mode are now
much better off using either Magit or the Git backend for Emacs's own
VC mode.

These modes were added over 10 years ago when Emacs's own Git support
was much less mature, and there weren't other mature modes in the wild
or shipped with Emacs itself.

These days these modes have few if any users, and users of git aren't
well served by us shipping these (some OS's install them alongside git
by default, which is confusing and leads users astray).

So let's remove these per Alexandre Julliard's message to the
ML[1]. If someone still wants these for some reason they're better
served by hosting these elsewhere (e.g. on ELPA), instead of us
distributing them with git.

However, since downstream packagers such as Debian are packaging this
as git-el it's less disruptive to still carry these files as Elisp
code that'll error out with a message suggesting alternatives, rather
than drop the files entirely[2].

Then rather than receive a cryptic load error when they upgrade
existing users will get an error directing them to the README file, or
to just stop requiring these modes. I think it makes sense to link to
GitHub's hosting of contrib/emacs/README (which'll be updated by the
time users see this) so they don't have to hunt down the packaged
README on their local system.

1. "Re: [PATCH] git.el: handle default excludesfile
properly" (87muzlwhb0.fsf@winehq.org) --
https://public-inbox.org/git/87muzlwhb0.fsf@winehq.org/

2. "Re: [PATCH v3] git{,-blame}.el: remove old bitrotting Emacs
code" (20180327165751.GA4343@aiede.svl.corp.google.com) --
https://public-inbox.org/git/20180327165751.GA4343@aiede.svl.corp.google.com/

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

gpg-interface: find the last gpg signature line

A signed tag has a detached signature like this:

object ...
[...more header...]

This is the tag body.

-----BEGIN PGP SIGNATURE-----
[opaque gpg data]
-----END PGP SIGNATURE-----

Our parser finds the _first_ line that appears to start a
PGP signature block, meaning we may be confused by a
signature (or a signature-like line) in the actual body.
Let's keep parsing and always find the final block, which
should be the detached signature over all of the preceding
content.

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

gpg-interface: extract gpg line matching helper

Let's separate the actual line-by-line parsing of signatures
from the notion of "is this a gpg signature line". That will
make it easier to do more refactoring of this loop in future
patches.

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

gpg-interface: fix const-correctness of "eol" pointer

We accidentally shed the "const" of our buffer by passing it
through memchr. Let's fix that, and while we're at it, move
our variable declaration inside the loop, which is the only
place that uses it.

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

gpg-interface: use size_t for signature buffer size

Even though our object sizes (from which these buffers would
come) are typically "unsigned long", this is something we'd
like to eventually fix (since it's only 32-bits even on
64-bit Windows). It makes more sense to use size_t when
taking an in-memory buffer.

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

gpg-interface: modernize function declarations

Let's drop "extern" from our declarations, which brings us
in line with our modern style guidelines. While we're
here, let's wrap some of the overly long lines, and move
docstrings for public functions to their declarations, since
they document the interface.

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

gpg-interface: handle bool user.signingkey

The config handler for user.signingkey does not check for a
boolean value, and thus:

git -c user.signingkey tag

will segfault. We could fix this and even shorten the code
by using git_config_string(). But our set_signing_key()
helper is used by other code outside of gpg-interface.c, so
we must keep it (and we may as well use it, because unlike
git_config_string() it does not leak when we overwrite an
old value).

Ironically, the handler for gpg.program just below _could_
use git_config_string() but doesn't. But since we're going
to touch that in a future patch, we'll leave it alone for
now. We will add some whitespace and returns in preparation
for adding more config keys, though.

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

t7004: fix mistaken tag name

We have a series of tests which create signed tags with
various properties, but one test accidentally verifies a tag
from much earlier in the series.

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

Makefile: add a DEVOPTS to get all of -Wextra

Change DEVOPTS to understand a "extra-all" option. When the DEVELOPER
flag is enabled we turn on -Wextra, but manually switch some of the
warnings it turns on off.

This is because we have many existing occurrences of them in the code
base. This mode will stop the suppression, let the developer see and
decide whether to fix them.

This change is a slight alteration of Nguyễn Thái Ngọc Duy
EAGER_DEVELOPER mode patch[1]

1. "[PATCH v3 3/3] Makefile: add EAGER_DEVELOPER
mode" (<20180329150322.10722-4-pclouds@gmail.com>;
https://public-inbox.org/git/20180329150322.10722-4-pclouds@gmail.com/)

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

Makefile: add a DEVOPTS to suppress -Werror under DEVELOPER

Add a DEVOPTS variable that'll be used to tweak the behavior of
DEVELOPER.

I've long wanted to use DEVELOPER=1 in my production builds, but on
some old systems I still get warnings, and thus the build would
fail. However if the build/tests fail for some other reason, it would
still be useful to scroll up and see what the relevant code is warning
about.

This change allows for that. Now setting DEVELOPER will set -Werror as
before, but if DEVOPTS=no-error is provided is set you'll get the same
warnings, but without -Werror.

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

Makefile: detect compiler and enable more warnings in DEVELOPER=1

The set of extra warnings we enable when DEVELOPER has to be
conservative because we can't assume any compiler version the
developer may use. Detect the compiler version so we know when it's
safe to enable -Wextra and maybe more.

These warning settings are mostly from my custom config.mak a long
time ago when I tried to enable as many warnings as possible that can
still build without showing warnings. Some of those warnings are
probably worth fixing instead of just suppressing in future.

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

connect.c: mark die_initial_contact() NORETURN

There is a series running in parallel with this one that adds code
like this

switch (...) {
case ...:
die_initial_contact();
case ...:

There is nothing wrong with this. There is no actual falling
through. But since gcc is not that smart and gcc 7.x introduces
-Wimplicit-fallthrough, it raises a false alarm in this case.

This class of warnings may be useful elsewhere, so instead of
suppressing the whole class, let's try to fix just this code. gcc is
smart enough to realize that no execution can continue after a
NORETURN function call and no longer raises the warning.

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

convert: add round trip check based on 'core.checkRoundtripEncoding'

UTF supports lossless conversion round tripping and conversions between
UTF and other encodings are mostly round trip safe as Unicode aims to be
a superset of all other character encodings. However, certain encodings
(e.g. SHIFT-JIS) are known to have round trip issues [1].

Add 'core.checkRoundtripEncoding', which contains a comma separated
list of encodings, to define for what encodings Git should check the
conversion round trip if they are used in the 'working-tree-encoding'
attribute.

Set SHIFT-JIS as default value for 'core.checkRoundtripEncoding'.

[1] https://support.microsoft.com/en-us/help/170559/prb-conversion-problem-between-shift-jis-and-unicode

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

convert: add tracing for 'working-tree-encoding' attribute

Add the GIT_TRACE_WORKING_TREE_ENCODING environment variable to enable
tracing for content that is reencoded with the 'working-tree-encoding'
attribute. This is useful to debug encoding issues.

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

convert: check for detectable errors in UTF encodings

Check that new content is valid with respect to the user defined
'working-tree-encoding' attribute.

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

convert: add 'working-tree-encoding' attribute

Git recognizes files encoded with ASCII or one of its supersets (e.g.
UTF-8 or ISO-8859-1) as text files. All other encodings are usually
interpreted as binary and consequently built-in Git text processing
tools (e.g. 'git diff') as well as most Git web front ends do not
visualize the content.

Add an attribute to tell Git what encoding the user has defined for a
given file. If the content is added to the index, then Git reencodes
the content to a canonical UTF-8 representation. On checkout Git will
reverse this operation.

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

utf8: add function to detect a missing UTF-16/32 BOM

If the endianness is not defined in the encoding name, then let's
be strict and require a BOM to avoid any encoding confusion. The
is_missing_required_utf_bom() function returns true if a required BOM
is missing.

The Unicode standard instructs to assume big-endian if there in no BOM
for UTF-16/32 [1][2]. However, the W3C/WHATWG encoding standard used
in HTML5 recommends to assume little-endian to "deal with deployed
content" [3]. Strictly requiring a BOM seems to be the safest option
for content in Git.

This function is used in a subsequent commit.

[1] http://unicode.org/faq/utf_bom.html#gen6
[2] http://www.unicode.org/versions/Unicode10.0.0/ch03.pdf
Section 3.10, D98, page 132
[3] https://encoding.spec.whatwg.org/#utf-16le

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

utf8: add function to detect prohibited UTF-16/32 BOM

Whenever a data stream is declared to be UTF-16BE, UTF-16LE, UTF-32BE
or UTF-32LE a BOM must not be used [1]. The function returns true if
this is the case.

This function is used in a subsequent commit.

[1] http://unicode.org/faq/utf_bom.html#bom10

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

utf8: teach same_encoding() alternative UTF encoding names

The function same_encoding() could only recognize alternative names for
UTF-8 encodings. Teach it to recognize all kinds of alternative UTF
encoding names (e.g. utf16).

While we are at it, fix a crash that would occur if same_encoding() was
called with a NULL argument and a non-NULL argument.

This function is used in a subsequent commit.

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

mem-pool: move reusable parts of memory pool into its own file

This moves the reusable parts of the memory pool logic used by
fast-import.c into its own file for use by other components.

Signed-off-by: Jameson Miller <jamill@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

replace-object: allow lookup_replace_object to handle arbitrary repositories

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

replace-object: allow do_lookup_replace_object to handle arbitrary repositories

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

replace-object: allow prepare_replace_object to handle arbitrary repositories

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

refs: allow for_each_replace_ref to handle arbitrary repositories

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

refs: store the main ref store inside the repository struct

This moves the 'main_ref_store', which was a global variable in refs.c
into the repository struct.

This patch does not deal with the parts in the refs subsystem which deal
with the submodules there. A later patch needs to get rid of the submodule
exposure in the refs API, such as 'get_submodule_ref_store(path)'.

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

replace-object: add repository argument to lookup_replace_object

Add a repository argument to allow callers of lookup_replace_object
to be more specific about which repository to handle. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

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

replace-object: add repository argument to do_lookup_replace_object

Add a repository argument to allow the do_lookup_replace_object caller
to be more specific about which repository to handle. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

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

replace-object: add repository argument to prepare_replace_object

Add a repository argument to allow the prepare_replace_object caller
to be more specific about which repository to handle. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

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

refs: add repository argument to for_each_replace_ref

Add a repository argument to allow for_each_replace_ref callers to be
more specific about which repository to handle. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

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

refs: add repository argument to get_main_ref_store

Add a repository argument to allow the get_main_ref_store caller
to be more specific about which repository to handle. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

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

replace-object: check_replace_refs is safe in multi repo environment

In e1111cef23 (inline lookup_replace_object() calls, 2011-05-15) a shortcut
for checking the object replacement was added by setting check_replace_refs
to 0 once the replacements were evaluated to not exist. This works fine in
with the assumption of only one repository in existence.

The assumption won't hold true any more when we work on multiple instances
of a repository structs (e.g. one struct per submodule), as the first
repository to be inspected may have no replacements and would set the
global variable. Other repositories would then completely omit their
evaluation of replacements.

This reverts back the meaning of the flag `check_replace_refs` of
"Do we need to check with the lookup table?" to "Do we need to read
the replacement definition?", adding the bypassing logic to
lookup_replace_object after the replacement definition was read.
As with the original patch, delay the renaming of the global variable

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

replace-object: eliminate replace objects prepared flag

Make the oidmap a pointer.

That way we eliminate the need for the global boolean
variable 'replace_object_prepared' as we can put this information
into the pointer being NULL or not.

Another advantage of this is that we would more quickly catch
code that tries to access replace-map without initializing it.

This also allows the '#include "oidmap.h"' introduced in a previous
patch to be replaced by the forward declaration of 'struct oidmap;'.
Keeping the type opaque discourages circumventing accessor functions;
not dragging in other headers avoids some compile time overhead.

One disadvantage of this is change is performance as we need to
pay the overhead for a malloc. The alternative of moving the
global variable into the object store is less modular code.

Helped-by: René Scharfe <l.s.r@web.de>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

object-store: move lookup_replace_object to replace-object.h

lookup_replace_object is a low-level function that most users of the
object store do not need to use directly.

Move it to replace-object.h to avoid a dependency loop in an upcoming
change to its inline definition that will make use of repository.h.

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

replace-object: move replace_map to object store

The relationship between an object X and another object Y that
replaces the object X is defined only within the scope of a
single repository.

The exception in reachability rule around these replacement objects
is also local to a repository (i.e. if traversal from refs reaches
X, then both X and Y are reachable and need to be kept from gc).

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

replace_object: use oidmap

Load the replace objects into an oidmap to allow for easy lookups in
constant time.

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

SubmittingPatches: mention the git contacts command

Instead of just mentioning 'git blame' and 'git shortlog', which make it
quite hard for new contributors to pick out the appropriate list of
people to cc on their patch series, mention the 'git contacts' utility,
which makes it much easier to get a reasonable list of contacts for a
change.

This should help new contributors pick out a reasonable cc list by
simply using a single command.

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

fast-import: introduce mem_pool type

Introduce the mem_pool type which encapsulates all the information necessary to
manage a pool of memory. This change moves the existing variables in
fast-import used to support the global memory pool to use this structure. It
also renames variables that are no longer used by memory pools to reflect their
more scoped usage.

These changes allow for the multiple instances of a memory pool to
exist and be reused outside of fast-import. In a future commit the
mem_pool type will be moved to its own file.

Signed-off-by: Jameson Miller <jamill@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fast-import: rename mem_pool type to mp_block

This is part of a patch series to extract the memory pool logic in
fast-import into a more generalized version. The existing mem_pool type
maps more closely to a "block of memory" (mp_block) in the more
generalized memory pool. This commit renames the mem_pool to mp_block to
reduce churn in future patches.

Signed-off-by: Jameson Miller <jamill@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Merge branch 'svn/authors-prog-2' of git://bogomips.org/git-svn

* 'svn/authors-prog-2' of git://bogomips.org/git-svn:
git-svn: allow empty email-address using authors-prog and authors-file
git-svn: search --authors-prog in PATH too

replace_object.c: rename to use dash in file name

This is more consistent with the project style. The majority of
Git's source files use dashes in preference to underscores in their file
names.

Noticed while adding a header corresponding to this file.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>

sha1_file.c: rename to use dash in file name

This is more consistent with the project style. The majority of Git's
source files use dashes in preference to underscores in their file names.

Signed-off-by: Stefan Beller <sbeller@google.com>

sha1_name.c: rename to use dash in file name

This is more consistent with the project style. The majority of Git's
source files use dashes in preference to underscores in their file names.

Signed-off-by: Stefan Beller <sbeller@google.com>

exec_cmd: rename to use dash in file name

This is more consistent with the project style. The majority of Git's
source files use dashes in preference to underscores in their file names.

Signed-off-by: Stefan Beller <sbeller@google.com>

unicode_width.h: rename to use dash in file name

This is more consistent with the project style. The majority of Git's
source files use dashes in preference to underscores in their file names.

Also adjust contrib/update-unicode as well.

Signed-off-by: Stefan Beller <sbeller@google.com>

write_or_die.c: rename to use dashes in file name

This is more consistent with the project style. The majority of Git's
source files use dashes in preference to underscores in their file names.

Signed-off-by: Stefan Beller <sbeller@google.com>

mingw/msvc: use the new-style RUNTIME_PREFIX helper

This change also allows us to stop overriding argv[0] with the absolute
path of the executable, allowing us to preserve e.g. the case of the
executable's file name.

This fixes https://github.com/git-for-windows/git/issues/1496 partially.

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

exec_cmd: provide a new-style RUNTIME_PREFIX helper for Windows

The RUNTIME_PREFIX feature comes from Git for Windows, but it was
enhanced to allow support for other platforms. While changing the
original idea, the concept was also improved by not forcing argv[0] to
be adjusted.

Let's allow the same for Windows by implementing a helper just as for
the other platforms.

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

exec_cmd: RUNTIME_PREFIX on some POSIX systems

Enable Git to resolve its own binary location using a variety of
OS-specific and generic methods, including:

- procfs via "/proc/self/exe" (Linux)
- _NSGetExecutablePath (Darwin)
- KERN_PROC_PATHNAME sysctl on BSDs.
- argv0, if absolute (all, including Windows).

This is used to enable RUNTIME_PREFIX support for non-Windows systems,
notably Linux and Darwin. When configured with RUNTIME_PREFIX, Git will
do a best-effort resolution of its executable path and automatically use
this as its "exec_path" for relative helper and data lookups, unless
explicitly overridden.

Small incidental formatting cleanup of "exec_cmd.c".

Signed-off-by: Dan Jacques <dnj@google.com>
Thanks-to: Robbie Iannucci <iannucci@google.com>
Thanks-to: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile: add Perl runtime prefix support

Broaden the RUNTIME_PREFIX flag to configure Git's Perl scripts to
locate the Git installation's Perl support libraries by resolving
against the script's path, rather than hard-coding that path at
build-time. Hard-coding at build time worked on previous
RUNTIME_PREFIX configurations (i.e., Windows) because the Perl
scripts were run within a virtual filesystem whose paths were
consistent regardless of the location of the actual installation.
This will no longer be the case for non-Windows RUNTIME_PREFIX users.

When enabled, RUNTIME_PREFIX now requires Perl's system paths to be
expressed relative to a common installation directory in the Makefile,
and uses that relationship to locate support files based on the known
starting point of the script being executed, much like RUNTIME_PREFIX
does for the Git binary.

This change enables Git's Perl scripts to work when their Git installation
is relocated or moved to another system, even when they are not in a
virtual filesystem environment.

Signed-off-by: Dan Jacques <dnj@google.com>
Thanks-to: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Thanks-to: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile: generate Perl header from template file

Currently, the generated Perl script headers are emitted by commands in
the Makefile. This mechanism restricts options to introduce alternative
header content, needed by Perl runtime prefix support, and obscures the
origin of the Perl script header.

Change the Makefile to generate a header by processing a template file and
move the header content into the "perl/" subdirectory. The generated
header content will now be stored in the "GIT-PERL-HEADER" file. This
allows the content of the Perl header to be controlled by changing the path
of the template in the Makefile.

Signed-off-by: Dan Jacques <dnj@google.com>
Thanks-to: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Thanks-to: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fsmonitor: force index write after full scan

fsmonitor currently only flags the index as dirty if the extension is being
added or removed. This is a performance optimization that recognizes you can
stat() a lot of files in less time than it takes to write out an updated index.

This patch makes a small enhancement and flags the index dirty if we end up
having to stat() all files and scan the entire working directory. The assumption
being that must be expensive or you would not have turned on the feature.

Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Revert "Merge branch 'en/rename-directory-detection'"

This reverts commit e4bb62fa1eeee689744b413e29a50b4d1dae6886, reversing
changes made to 468165c1d8a442994a825f3684528361727cd8c0.

The topic appears to inflict severe regression in renaming merges,
even though the promise of it was that it would improve them.

We do not yet know which exact change in the topic was wrong, but in
the meantime, let's play it safe and revert it out of 'master'
before real Git-using projects are harmed.

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

fsmonitor: fix incorrect buffer size when printing version number

This is a trivial bug fix for passing the incorrect size to snprintf() when
outputting the version. It should be passing the size of the destination buffer
rather than the size of the value being printed.

Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/perf: add scripts to bisect performance regressions

The new bisect_regression script can be used to automatically bisect
performance regressions. It will pass the new bisect_run_script to
`git bisect run`.

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

perf/run: add --subsection option

This new option makes it possible to run perf tests as defined
in only one subsection of a config file.

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

The third batch for 2.18

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

Merge branch 'eb/cred-helper-ignore-sigpipe'

When credential helper exits very quickly without reading its
input, it used to cause Git to die with SIGPIPE, which has been
fixed.

* eb/cred-helper-ignore-sigpipe:
credential: ignore SIGPIPE when writing to credential helpers

Merge branch 'lv/tls-1.3'

When built with more recent cURL, GIT_SSL_VERSION can now specify
"tlsv1.3" as its value.

* lv/tls-1.3:
http: allow use of TLS 1.3

Merge branch 'pk/test-avoid-pipe-hiding-exit-status'

Test cleanup.

* pk/test-avoid-pipe-hiding-exit-status:
test: avoid pipes in git related commands for test

Merge branch 'rs/status-with-removed-submodule'

"git submodule status" misbehaved on a submodule that has been
removed from the working tree.

* rs/status-with-removed-submodule:
submodule: check for NULL return of get_submodule_ref_store()

Merge branch 'nd/combined-test-helper'

Small test-helper programs have been consolidated into a single
binary.

* nd/combined-test-helper: (36 commits)
t/helper: merge test-write-cache into test-tool
t/helper: merge test-wildmatch into test-tool
t/helper: merge test-urlmatch-normalization into test-tool
t/helper: merge test-subprocess into test-tool
t/helper: merge test-submodule-config into test-tool
t/helper: merge test-string-list into test-tool
t/helper: merge test-strcmp-offset into test-tool
t/helper: merge test-sigchain into test-tool
t/helper: merge test-sha1-array into test-tool
t/helper: merge test-scrap-cache-tree into test-tool
t/helper: merge test-run-command into test-tool
t/helper: merge test-revision-walking into test-tool
t/helper: merge test-regex into test-tool
t/helper: merge test-ref-store into test-tool
t/helper: merge test-read-cache into test-tool
t/helper: merge test-prio-queue into test-tool
t/helper: merge test-path-utils into test-tool
t/helper: merge test-online-cpus into test-tool
t/helper: merge test-mktemp into test-tool
t/helper: merge (unused) test-mergesort into test-tool
...

Merge branch 'sb/packfiles-in-repository'

Refactoring of the internal global data structure continues.

* sb/packfiles-in-repository:
packfile: keep prepare_packed_git() private
packfile: allow find_pack_entry to handle arbitrary repositories
packfile: add repository argument to find_pack_entry
packfile: allow reprepare_packed_git to handle arbitrary repositories
packfile: allow prepare_packed_git to handle arbitrary repositories
packfile: allow prepare_packed_git_one to handle arbitrary repositories
packfile: add repository argument to reprepare_packed_git
packfile: add repository argument to prepare_packed_git
packfile: add repository argument to prepare_packed_git_one
packfile: allow install_packed_git to handle arbitrary repositories
packfile: allow rearrange_packed_git to handle arbitrary repositories
packfile: allow prepare_packed_git_mru to handle arbitrary repositories

Merge branch 'sb/object-store'

Refactoring the internal global data structure to make it possible
to open multiple repositories, work with and then close them.

Rerolled by Duy on top of a separate preliminary clean-up topic.
The resulting structure of the topics looked very sensible.

* sb/object-store: (27 commits)
sha1_file: allow sha1_loose_object_info to handle arbitrary repositories
sha1_file: allow map_sha1_file to handle arbitrary repositories
sha1_file: allow map_sha1_file_1 to handle arbitrary repositories
sha1_file: allow open_sha1_file to handle arbitrary repositories
sha1_file: allow stat_sha1_file to handle arbitrary repositories
sha1_file: allow sha1_file_name to handle arbitrary repositories
sha1_file: add repository argument to sha1_loose_object_info
sha1_file: add repository argument to map_sha1_file
sha1_file: add repository argument to map_sha1_file_1
sha1_file: add repository argument to open_sha1_file
sha1_file: add repository argument to stat_sha1_file
sha1_file: add repository argument to sha1_file_name
sha1_file: allow prepare_alt_odb to handle arbitrary repositories
sha1_file: allow link_alt_odb_entries to handle arbitrary repositories
sha1_file: add repository argument to prepare_alt_odb
sha1_file: add repository argument to link_alt_odb_entries
sha1_file: add repository argument to read_info_alternates
sha1_file: add repository argument to link_alt_odb_entry
sha1_file: add raw_object_store argument to alt_odb_usable
pack: move approximate object count to object store
...

Merge branch 'jc/test-must-be-empty'

Test helper update.

* jc/test-must-be-empty:
test_must_be_empty: simplify file existence check

Merge branch 'cc/perf-aggregate-sort'

Perf-test update.

* cc/perf-aggregate-sort:
perf/aggregate: add --sort-by=regression option
perf/aggregate: add display_dir()

Merge branch 'ab/doc-hash-brokenness'

Doc updates.

* ab/doc-hash-brokenness:
doc hash-function-transition: clarify what SHAttered means
doc hash-function-transition: clarify how older gits die on NewHash

Merge branch 'bc/hash-independent-tests'

Tests that rely on the exact hardcoded values of object names have
been updated in preparation for hash function migration.

* bc/hash-independent-tests:
t2107: abstract away SHA-1-specific constants
t2101: abstract away SHA-1-specific constants
t2101: modernize test style
t2020: abstract away SHA-1 specific constants
t1507: abstract away SHA-1-specific constants
t1411: abstract away SHA-1-specific constants
t1405: sort reflog entries in a hash-independent way
t1300: abstract away SHA-1-specific constants
t1304: abstract away SHA-1-specific constants
t1011: abstract away SHA-1-specific constants

Merge branch 'ab/drop-contrib-examples'

* ab/drop-contrib-examples:
Remove contrib/examples/*

commit-graph: implement "--append" option

Teach git-commit-graph to add all commits from the existing
commit-graph file to the file about to be written. This should be
used when adding new commits without performing garbage collection.

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

commit-graph: build graph from starting commits

Teach git-commit-graph to read commits from stdin when the
--stdin-commits flag is specified. Commits reachable from these
commits are added to the graph. This is a much faster way to construct
the graph than inspecting all packed objects, but is restricted to
known tips.

For the Linux repository, 700,000+ commits were added to the graph
file starting from 'master' in 7-9 seconds, depending on the number
of packfiles in the repo (1, 24, or 120).

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

commit-graph: read only from specific pack-indexes

Teach git-commit-graph to inspect the objects only in a certain list
of pack-indexes within the given pack directory. This allows updating
the commit graph iteratively.

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

commit: integrate commit graph with commit parsing

Teach Git to inspect a commit graph file to supply the contents of a
struct commit when calling parse_commit_gently(). This implementation
satisfies all post-conditions on the struct commit, including loading
parents, the root tree, and the commit date.

If core.commitGraph is false, then do not check graph files.

In test script t5318-commit-graph.sh, add output-matching conditions on
read-only graph operations.

By loading commits from the graph instead of parsing commit buffers, we
save a lot of time on long commit walks. Here are some performance
results for a copy of the Linux repository where 'master' has 678,653
reachable commits and is behind 'origin/master' by 59,929 commits.

| Command | Before | After | Rel % |
|----------------------------------|--------|--------|-------|
| log --oneline --topo-order -1000 | 8.31s | 0.94s | -88% |
| branch -vv | 1.02s | 0.14s | -86% |
| rev-list --all | 5.89s | 1.07s | -81% |
| rev-list --all --objects | 66.15s | 58.45s | -11% |

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

commit-graph: close under reachability

Teach write_commit_graph() to walk all parents from the commits
discovered in packfiles. This prevents gaps given by loose objects or
previously-missed packfiles.

Also automatically add commits from the existing graph file, if it
exists.

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

commit-graph: add core.commitGraph setting

The commit graph feature is controlled by the new core.commitGraph config
setting. This defaults to 0, so the feature is opt-in.

The intention of core.commitGraph is that a user can always stop checking
for or parsing commit graph files if core.commitGraph=0.

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

commit-graph: implement git commit-graph read

Teach git-commit-graph to read commit graph files and summarize their contents.

Use the read subcommand to verify the contents of a commit graph file in the
tests.

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

perl: fix installing modules from contrib

Commit 20d2a30f (Makefile: replace perl/Makefile.PL with simple make rules)
removed a target that allowed Makefiles from contrib/ to get the correct
install path. This introduces a new target for main Makefile and fixes
installation for Mediawiki module.

v2: Pass prefix as that can have influence as well, add single quotes
for _SQ variant.

Signed-off-by: Christian Hesse <mail@eworm.de>