git/contrib
brian m. carlson 7bc341e21b git-compat-util: add a test balloon for C99 support
The C99 standard was released in January 1999, now 22 years ago.  It
provides a variety of useful features, including variadic arguments for
macros, declarations after statements, designated initializers, and a
wide variety of other useful features, many of which we already use.

We'd like to take advantage of these features, but we want to be
cautious.  As far as we know, all major compilers now support C99 or a
later C standard, such as C11 or C17.  POSIX has required C99 support as
a requirement for the 2001 revision, so we can safely assume any POSIX
system which we are interested in supporting has C99.

Even MSVC, long a holdout against modern C, now supports both C11 and
C17 with an appropriate update.  Moreover, even if people are using an
older version of MSVC on these systems, they will generally need some
implementation of the standard Unix utilities for the testsuite, and GNU
coreutils, the most common option, has required C99 since 2009.
Therefore, we can safely assume that a suitable version of GCC or clang
is available to users even if their version of MSVC is not sufficiently
capable.

Let's add a test balloon to git-compat-util.h to see if anyone is using
an older compiler.  We'll add a comment telling people how to enable
this functionality on GCC and Clang, even though modern versions of both
will automatically do the right thing, and ask people still experiencing
a problem to report that to us on the list.

Note that C89 compilers don't provide the __STDC_VERSION__ macro, so we
use a well-known hack of using "- 0".  On compilers with this macro, it
doesn't change the value, and on C89 compilers, the macro will be
replaced with nothing, and our value will be 0.

For sparse, we explicitly request the gnu99 style because we've
traditionally taken advantage of some GCC- and clang-specific extensions
when available and we'd like to retain the ability to do that.  sparse
also defaults to C89 without it, so things will fail for us if we don't.

Update the cmake configuration to require C11 for MSVC.  We do this
because this will make MSVC to use C11, since it does not explicitly
support C99.  We do this with a compiler options because setting the
C_STANDARD option does not work in our CI on MSVC and at the moment, we
don't want to require C11 for Unix compilers.

In the Makefile, don't set any compiler flags for the compiler itself,
since on some systems, such as FreeBSD, we actually need C11, and asking
for C99 causes things to fail to compile.  The error message should make
it obvious what's going wrong and allow a user to set the appropriate
option when building in the event they're using a Unix compiler that
doesn't support it by default.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-01 14:50:01 -08:00
..
buildsystems git-compat-util: add a test balloon for C99 support 2021-12-01 14:50:01 -08:00
coccinelle use xopen() to handle fatal open(2) failures 2021-08-25 14:39:08 -07:00
completion Merge branch 'ti/tcsh-completion-regression-fix' into maint 2021-10-12 13:51:24 -07:00
contacts git-contacts: also recognise "Reported-by:" 2017-07-27 09:42:55 -07:00
credential *.c static functions: add missing __attribute__((format)) 2021-07-13 15:20:20 -07:00
diff-highlight diff-highlight: correctly match blank lines for flush 2020-09-21 22:33:28 -07:00
emacs git{,-blame}.el: remove old bitrotting Emacs code 2018-04-16 17:25:49 +09:00
examples Merge branch 'bw/c-plus-plus' into ds/lazy-load-trees 2018-04-11 10:46:32 +09:00
fast-import import-tars: ignore the global PAX header 2020-03-24 14:39:47 -07:00
git-jump contrib/git-jump/git-jump: jump to exact location 2018-06-22 12:59:02 -07:00
git-shell-commands
hg-to-git hg-to-git: make it compatible with both python3 and python2 2019-09-18 12:03:05 -07:00
hooks multimail: stop shipping a copy 2021-06-11 13:35:19 +09:00
long-running-filter docs: warn about possible '=' in clean/smudge filter process values 2016-12-06 11:29:52 -08:00
mw-to-git t: fix whitespace around && 2021-06-08 10:08:01 +09:00
persistent-https docs/config: mention protocol implications of url.insteadOf 2017-06-01 10:07:10 +09:00
remote-helpers contrib: git-remote-{bzr,hg} placeholders don't need Python 2017-03-03 11:09:34 -08:00
stats
subtree subtree: fix assumption about the directory separator 2021-06-15 11:38:28 +09:00
thunderbird-patch-inline contrib/thunderbird-patch-inline/appp.sh: use the $( ... ) construct for command substitution 2015-12-27 15:33:13 -08:00
update-unicode unicode_width.h: rename to use dash in file name 2018-04-11 18:11:00 +09:00
vscode vscode: let cSpell work on commit messages, too 2018-07-30 13:14:39 -07:00
workdir git-new-workdir: mark script as LF-only 2017-05-10 13:32:50 +09:00
coverage-diff.sh contrib: add coverage-diff script 2018-10-10 10:11:35 +09:00
git-resurrect.sh contrib/git-resurrect.sh: use hash-agnostic OID pattern 2020-10-08 11:48:56 -07:00
README
remotes2config.sh
rerere-train.sh contrib/rerere-train: optionally overwrite existing resolutions 2017-07-26 13:38:48 -07:00

Contributed Software

Although these pieces are available as part of the official git
source tree, they are in somewhat different status.  The
intention is to keep interesting tools around git here, maybe
even experimental ones, to give users an easier access to them,
and to give tools wider exposure, so that they can be improved
faster.

I am not expecting to touch these myself that much.  As far as
my day-to-day operation is concerned, these subdirectories are
owned by their respective primary authors.  I am willing to help
if users of these components and the contrib/ subtree "owners"
have technical/design issues to resolve, but the initiative to
fix and/or enhance things _must_ be on the side of the subtree
owners.  IOW, I won't be actively looking for bugs and rooms for
enhancements in them as the git maintainer -- I may only do so
just as one of the users when I want to scratch my own itch.  If
you have patches to things in contrib/ area, the patch should be
first sent to the primary author, and then the primary author
should ack and forward it to me (git pull request is nicer).
This is the same way as how I have been treating gitk, and to a
lesser degree various foreign SCM interfaces, so you know the
drill.

I expect that things that start their life in the contrib/ area
to graduate out of contrib/ once they mature, either by becoming
projects on their own, or moving to the toplevel directory.  On
the other hand, I expect I'll be proposing removal of disused
and inactive ones from time to time.

If you have new things to add to this area, please first propose
it on the git mailing list, and after a list discussion proves
there are some general interests (it does not have to be a
list-wide consensus for a tool targeted to a relatively narrow
audience -- for example I do not work with projects whose
upstream is svn, so I have no use for git-svn myself, but it is
of general interest for people who need to interoperate with SVN
repositories in a way git-svn works better than git-svnimport),
submit a patch to create a subdirectory of contrib/ and put your
stuff there.

-jc