2007-11-08 00:33:19 +00:00
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Like other projects, we also have some guidelines to keep to the
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2015-04-13 12:54:14 +00:00
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code. For Git in general, a few rough rules are:
|
2007-11-08 00:33:19 +00:00
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- Most importantly, we never say "It's in POSIX; we'll happily
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ignore your needs should your system not conform to it."
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We live in the real world.
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- However, we often say "Let's stay away from that construct,
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it's not even in POSIX".
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- In spite of the above two rules, we sometimes say "Although
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this is not in POSIX, it (is so convenient | makes the code
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much more readable | has other good characteristics) and
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practically all the platforms we care about support it, so
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let's use it".
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Again, we live in the real world, and it is sometimes a
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judgement call, the decision based more on real world
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constraints people face than what the paper standard says.
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2014-04-30 21:23:26 +00:00
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- Fixing style violations while working on a real change as a
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preparatory clean-up step is good, but otherwise avoid useless code
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churn for the sake of conforming to the style.
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"Once it _is_ in the tree, it's not really worth the patch noise to
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go and fix it up."
|
2017-05-05 10:08:03 +00:00
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Cf. http://lkml.iu.edu/hypermail/linux/kernel/1001.3/01069.html
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2014-04-30 21:23:26 +00:00
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2013-02-06 19:49:01 +00:00
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Make your code readable and sensible, and don't try to be clever.
|
2007-11-08 00:33:19 +00:00
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As for more concrete guidelines, just imitate the existing code
|
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(this is a good guideline, no matter which project you are
|
2009-01-26 08:32:22 +00:00
|
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|
contributing to). It is always preferable to match the _local_
|
2013-01-21 19:17:53 +00:00
|
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convention. New code added to Git suite is expected to match
|
2009-01-26 08:32:22 +00:00
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|
the overall style of existing code. Modifications to existing
|
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code is expected to match the style the surrounding code already
|
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uses (even if it doesn't match the overall style of existing code).
|
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But if you must have a list of rules, here they are.
|
2007-11-08 00:33:19 +00:00
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For shell scripts specifically (not exhaustive):
|
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|
2010-12-03 16:47:35 +00:00
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|
- We use tabs for indentation.
|
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|
2014-04-30 21:24:08 +00:00
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|
- Case arms are indented at the same depth as case and esac lines,
|
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like this:
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case "$variable" in
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pattern1)
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do this
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;;
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pattern2)
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do that
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;;
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esac
|
2010-12-03 16:47:35 +00:00
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|
2012-02-24 23:12:57 +00:00
|
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|
- Redirection operators should be written with space before, but no
|
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space after them. In other words, write 'echo test >"$file"'
|
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instead of 'echo test> $file' or 'echo test > $file'. Note that
|
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even though it is not required by POSIX to double-quote the
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redirection target in a variable (as shown above), our code does so
|
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because some versions of bash issue a warning without the quotes.
|
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|
|
2014-04-30 21:24:24 +00:00
|
|
|
(incorrect)
|
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|
cat hello > world < universe
|
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|
echo hello >$world
|
|
|
|
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|
(correct)
|
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cat hello >world <universe
|
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|
echo hello >"$world"
|
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|
2007-11-08 00:33:19 +00:00
|
|
|
- We prefer $( ... ) for command substitution; unlike ``, it
|
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|
properly nests. It should have been the way Bourne spelled
|
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|
it from day one, but unfortunately isn't.
|
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|
2012-02-24 23:12:58 +00:00
|
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|
- If you want to find out if a command is available on the user's
|
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|
$PATH, you should use 'type <command>', instead of 'which <command>'.
|
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|
The output of 'which' is not machine parseable and its exit code
|
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|
is not reliable across platforms.
|
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|
2010-10-13 18:15:14 +00:00
|
|
|
- We use POSIX compliant parameter substitutions and avoid bashisms;
|
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|
namely:
|
2007-11-08 00:33:19 +00:00
|
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|
|
2010-10-13 18:15:14 +00:00
|
|
|
- We use ${parameter-word} and its [-=?+] siblings, and their
|
|
|
|
colon'ed "unset or null" form.
|
2007-11-08 00:33:19 +00:00
|
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|
|
2010-10-13 18:15:14 +00:00
|
|
|
- We use ${parameter#word} and its [#%] siblings, and their
|
|
|
|
doubled "longest matching" form.
|
2007-11-08 00:33:19 +00:00
|
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|
|
2010-10-13 18:15:14 +00:00
|
|
|
- No "Substring Expansion" ${parameter:offset:length}.
|
2010-09-22 19:15:37 +00:00
|
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|
2010-10-13 18:15:14 +00:00
|
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|
- No shell arrays.
|
2007-11-08 00:33:19 +00:00
|
|
|
|
2010-10-13 18:15:14 +00:00
|
|
|
- No strlen ${#parameter}.
|
2007-11-08 00:33:19 +00:00
|
|
|
|
2010-10-13 18:15:14 +00:00
|
|
|
- No pattern replacement ${parameter/pattern/string}.
|
2007-11-08 00:33:19 +00:00
|
|
|
|
2010-10-13 18:15:14 +00:00
|
|
|
- We use Arithmetic Expansion $(( ... )).
|
|
|
|
|
|
|
|
- Inside Arithmetic Expansion, spell shell variables with $ in front
|
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|
of them, as some shells do not grok $((x)) while accepting $(($x))
|
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|
just fine (e.g. dash older than 0.5.4).
|
2007-11-08 00:33:19 +00:00
|
|
|
|
|
|
|
- We do not use Process Substitution <(list) or >(list).
|
|
|
|
|
2012-08-15 17:06:01 +00:00
|
|
|
- Do not write control structures on a single line with semicolon.
|
|
|
|
"then" should be on the next line for if statements, and "do"
|
|
|
|
should be on the next line for "while" and "for".
|
|
|
|
|
2014-04-30 21:24:52 +00:00
|
|
|
(incorrect)
|
|
|
|
if test -f hello; then
|
|
|
|
do this
|
|
|
|
fi
|
|
|
|
|
|
|
|
(correct)
|
|
|
|
if test -f hello
|
|
|
|
then
|
|
|
|
do this
|
|
|
|
fi
|
|
|
|
|
2018-10-05 21:54:02 +00:00
|
|
|
- If a command sequence joined with && or || or | spans multiple
|
|
|
|
lines, put each command on a separate line and put && and || and |
|
|
|
|
operators at the end of each line, rather than the start. This
|
|
|
|
means you don't need to use \ to join lines, since the above
|
|
|
|
operators imply the sequence isn't finished.
|
|
|
|
|
|
|
|
(incorrect)
|
|
|
|
grep blob verify_pack_result \
|
|
|
|
| awk -f print_1.awk \
|
|
|
|
| sort >actual &&
|
|
|
|
...
|
|
|
|
|
|
|
|
(correct)
|
|
|
|
grep blob verify_pack_result |
|
|
|
|
awk -f print_1.awk |
|
|
|
|
sort >actual &&
|
|
|
|
...
|
|
|
|
|
2007-11-08 00:33:19 +00:00
|
|
|
- We prefer "test" over "[ ... ]".
|
|
|
|
|
|
|
|
- We do not write the noiseword "function" in front of shell
|
|
|
|
functions.
|
|
|
|
|
2014-04-30 21:25:11 +00:00
|
|
|
- We prefer a space between the function name and the parentheses,
|
|
|
|
and no space inside the parentheses. The opening "{" should also
|
|
|
|
be on the same line.
|
|
|
|
|
|
|
|
(incorrect)
|
|
|
|
my_function(){
|
|
|
|
...
|
|
|
|
|
|
|
|
(correct)
|
|
|
|
my_function () {
|
|
|
|
...
|
2012-08-15 17:06:01 +00:00
|
|
|
|
2008-03-02 02:18:16 +00:00
|
|
|
- As to use of grep, stick to a subset of BRE (namely, no \{m,n\},
|
2014-03-31 22:11:44 +00:00
|
|
|
[::], [==], or [..]) for portability.
|
2008-03-02 02:18:16 +00:00
|
|
|
|
|
|
|
- We do not use \{m,n\};
|
|
|
|
|
|
|
|
- We do not use -E;
|
|
|
|
|
2014-03-31 22:11:44 +00:00
|
|
|
- We do not use ? or + (which are \{0,1\} and \{1,\}
|
2008-03-02 02:18:16 +00:00
|
|
|
respectively in BRE) but that goes without saying as these
|
|
|
|
are ERE elements not BRE (note that \? and \+ are not even part
|
|
|
|
of BRE -- making them accessible from BRE is a GNU extension).
|
|
|
|
|
i18n: add infrastructure for translating Git with gettext
Change the skeleton implementation of i18n in Git to one that can show
localized strings to users for our C, Shell and Perl programs using
either GNU libintl or the Solaris gettext implementation.
This new internationalization support is enabled by default. If
gettext isn't available, or if Git is compiled with
NO_GETTEXT=YesPlease, Git falls back on its current behavior of
showing interface messages in English. When using the autoconf script
we'll auto-detect if the gettext libraries are installed and act
appropriately.
This change is somewhat large because as well as adding a C, Shell and
Perl i18n interface we're adding a lot of tests for them, and for
those tests to work we need a skeleton PO file to actually test
translations. A minimal Icelandic translation is included for this
purpose. Icelandic includes multi-byte characters which makes it easy
to test various edge cases, and it's a language I happen to
understand.
The rest of the commit message goes into detail about various
sub-parts of this commit.
= Installation
Gettext .mo files will be installed and looked for in the standard
$(prefix)/share/locale path. GIT_TEXTDOMAINDIR can also be set to
override that, but that's only intended to be used to test Git itself.
= Perl
Perl code that's to be localized should use the new Git::I18n
module. It imports a __ function into the caller's package by default.
Instead of using the high level Locale::TextDomain interface I've
opted to use the low-level (equivalent to the C interface)
Locale::Messages module, which Locale::TextDomain itself uses.
Locale::TextDomain does a lot of redundant work we don't need, and
some of it would potentially introduce bugs. It tries to set the
$TEXTDOMAIN based on package of the caller, and has its own
hardcoded paths where it'll search for messages.
I found it easier just to completely avoid it rather than try to
circumvent its behavior. In any case, this is an issue wholly
internal Git::I18N. Its guts can be changed later if that's deemed
necessary.
See <AANLkTilYD_NyIZMyj9dHtVk-ylVBfvyxpCC7982LWnVd@mail.gmail.com> for
a further elaboration on this topic.
= Shell
Shell code that's to be localized should use the git-sh-i18n
library. It's basically just a wrapper for the system's gettext.sh.
If gettext.sh isn't available we'll fall back on gettext(1) if it's
available. The latter is available without the former on Solaris,
which has its own non-GNU gettext implementation. We also need to
emulate eval_gettext() there.
If neither are present we'll use a dumb printf(1) fall-through
wrapper.
= About libcharset.h and langinfo.h
We use libcharset to query the character set of the current locale if
it's available. I.e. we'll use it instead of nl_langinfo if
HAVE_LIBCHARSET_H is set.
The GNU gettext manual recommends using langinfo.h's
nl_langinfo(CODESET) to acquire the current character set, but on
systems that have libcharset.h's locale_charset() using the latter is
either saner, or the only option on those systems.
GNU and Solaris have a nl_langinfo(CODESET), FreeBSD can use either,
but MinGW and some others need to use libcharset.h's locale_charset()
instead.
=Credits
This patch is based on work by Jeff Epler <jepler@unpythonic.net> who
did the initial Makefile / C work, and a lot of comments from the Git
mailing list, including Jonathan Nieder, Jakub Narebski, Johannes
Sixt, Erik Faye-Lund, Peter Krefting, Junio C Hamano, Thomas Rast and
others.
[jc: squashed a small Makefile fix from Ramsay]
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-17 23:14:42 +00:00
|
|
|
- Use Git's gettext wrappers in git-sh-i18n to make the user
|
|
|
|
interface translatable. See "Marking strings for translation" in
|
|
|
|
po/README.
|
|
|
|
|
2014-05-20 18:12:02 +00:00
|
|
|
- We do not write our "test" command with "-a" and "-o" and use "&&"
|
|
|
|
or "||" to concatenate multiple "test" commands instead, because
|
|
|
|
the use of "-a/-o" is often error-prone. E.g.
|
|
|
|
|
|
|
|
test -n "$x" -a "$a" = "$b"
|
|
|
|
|
|
|
|
is buggy and breaks when $x is "=", but
|
|
|
|
|
|
|
|
test -n "$x" && test "$a" = "$b"
|
|
|
|
|
|
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|
does not have such a problem.
|
|
|
|
|
|
|
|
|
2007-11-08 00:33:19 +00:00
|
|
|
For C programs:
|
|
|
|
|
|
|
|
- We use tabs to indent, and interpret tabs as taking up to
|
|
|
|
8 spaces.
|
|
|
|
|
|
|
|
- We try to keep to at most 80 characters per line.
|
|
|
|
|
2016-02-25 08:42:22 +00:00
|
|
|
- As a Git developer we assume you have a reasonably modern compiler
|
|
|
|
and we recommend you to enable the DEVELOPER makefile knob to
|
|
|
|
ensure your patch is clear of all compiler warnings we care about,
|
|
|
|
by e.g. "echo DEVELOPER=1 >>config.mak".
|
|
|
|
|
2013-01-21 19:17:53 +00:00
|
|
|
- We try to support a wide range of C compilers to compile Git with,
|
2012-12-16 19:36:00 +00:00
|
|
|
including old ones. That means that you should not use C99
|
|
|
|
initializers, even if a lot of compilers grok it.
|
|
|
|
|
|
|
|
- Variables have to be declared at the beginning of the block.
|
|
|
|
|
|
|
|
- NULL pointers shall be written as NULL, not as 0.
|
|
|
|
|
2007-11-08 00:33:19 +00:00
|
|
|
- When declaring pointers, the star sides with the variable
|
|
|
|
name, i.e. "char *string", not "char* string" or
|
|
|
|
"char * string". This makes it easier to understand code
|
|
|
|
like "char *string, c;".
|
|
|
|
|
2014-02-28 06:17:25 +00:00
|
|
|
- Use whitespace around operators and keywords, but not inside
|
|
|
|
parentheses and not around functions. So:
|
|
|
|
|
|
|
|
while (condition)
|
|
|
|
func(bar + 1);
|
|
|
|
|
|
|
|
and not:
|
|
|
|
|
|
|
|
while( condition )
|
|
|
|
func (bar+1);
|
|
|
|
|
2007-11-08 00:33:19 +00:00
|
|
|
- We avoid using braces unnecessarily. I.e.
|
|
|
|
|
|
|
|
if (bla) {
|
|
|
|
x = 1;
|
|
|
|
}
|
|
|
|
|
2017-01-17 20:05:04 +00:00
|
|
|
is frowned upon. But there are a few exceptions:
|
|
|
|
|
|
|
|
- When the statement extends over a few lines (e.g., a while loop
|
|
|
|
with an embedded conditional, or a comment). E.g.:
|
|
|
|
|
|
|
|
while (foo) {
|
|
|
|
if (x)
|
|
|
|
one();
|
|
|
|
else
|
|
|
|
two();
|
|
|
|
}
|
|
|
|
|
|
|
|
if (foo) {
|
|
|
|
/*
|
|
|
|
* This one requires some explanation,
|
|
|
|
* so we're better off with braces to make
|
|
|
|
* it obvious that the indentation is correct.
|
|
|
|
*/
|
|
|
|
doit();
|
|
|
|
}
|
|
|
|
|
|
|
|
- When there are multiple arms to a conditional and some of them
|
|
|
|
require braces, enclose even a single line block in braces for
|
|
|
|
consistency. E.g.:
|
|
|
|
|
|
|
|
if (foo) {
|
|
|
|
doit();
|
|
|
|
} else {
|
|
|
|
one();
|
|
|
|
two();
|
|
|
|
three();
|
|
|
|
}
|
2007-11-08 00:33:19 +00:00
|
|
|
|
2014-04-30 21:25:47 +00:00
|
|
|
- We try to avoid assignments in the condition of an "if" statement.
|
2008-05-22 23:26:09 +00:00
|
|
|
|
2007-11-08 00:33:19 +00:00
|
|
|
- Try to make your code understandable. You may put comments
|
|
|
|
in, but comments invariably tend to stale out when the code
|
|
|
|
they were describing changes. Often splitting a function
|
|
|
|
into two makes the intention of the code much clearer.
|
|
|
|
|
2013-10-12 00:45:46 +00:00
|
|
|
- Multi-line comments include their delimiters on separate lines from
|
|
|
|
the text. E.g.
|
|
|
|
|
|
|
|
/*
|
|
|
|
* A very long
|
|
|
|
* multi-line comment.
|
|
|
|
*/
|
|
|
|
|
2014-04-18 17:48:08 +00:00
|
|
|
Note however that a comment that explains a translatable string to
|
|
|
|
translators uses a convention of starting with a magic token
|
C style: use standard style for "TRANSLATORS" comments
Change all the "TRANSLATORS: [...]" comments in the C code to use the
regular Git coding style, and amend the style guide so that the
example there uses that style.
This custom style was necessary back in 2010 when the gettext support
was initially added, and was subsequently documented in commit
cbcfd4e3ea ("i18n: mention "TRANSLATORS:" marker in
Documentation/CodingGuidelines", 2014-04-18).
GNU xgettext hasn't had the parsing limitation that necessitated this
exception for almost 3 years. Since its 0.19 release on 2014-06-02
it's been able to recognize TRANSLATOR comments in the standard Git
comment syntax[1].
Usually we'd like to keep compatibility with software that's that
young, but in this case literally the only person who needs to be
using a gettext newer than 3 years old is Jiang Xin (the only person
who runs & commits "make pot" results), so I think in this case we can
make an exception.
This xgettext parsing feature was added after a thread on the Git
mailing list[2] which continued on the bug-gettext[3] list, but we
never subsequently changed our style & styleguide, do so.
There are already longstanding changes in git that use the standard
comment style & have their TRANSLATORS comments extracted properly
without getting the literal "*"'s mixed up in the text, as would
happen before xgettext 0.19.
Commit 7ff2683253 ("builtin-am: implement -i/--interactive",
2015-08-04) added one such comment, which in commit df0617bfa7 ("l10n:
git.pot: v2.6.0 round 1 (123 new, 41 removed)", 2015-09-05) got picked
up in the po/git.pot file with the right format, showing that Jiang
already runs a modern xgettext.
The xgettext parser does not handle the sort of non-standard comment
style that I'm amending here in sequencer.c, but that isn't standard
Git comment syntax anyway. With this change to sequencer.c & "make
pot" the comment in the pot file is now correct:
#. TRANSLATORS: %s will be "revert", "cherry-pick" or
-#. * "rebase -i".
+#. "rebase -i".
1. http://git.savannah.gnu.org/cgit/gettext.git/commit/?id=10af7fe6bd
2. <2ce9ec406501d112e032c8208417f8100bed04c6.1397712142.git.worldhello.net@gmail.com>
(https://public-inbox.org/git/2ce9ec406501d112e032c8208417f8100bed04c6.1397712142.git.worldhello.net@gmail.com/)
3. https://lists.gnu.org/archive/html/bug-gettext/2014-04/msg00016.html
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-11 21:20:12 +00:00
|
|
|
"TRANSLATORS: ", e.g.
|
2014-04-18 17:48:08 +00:00
|
|
|
|
C style: use standard style for "TRANSLATORS" comments
Change all the "TRANSLATORS: [...]" comments in the C code to use the
regular Git coding style, and amend the style guide so that the
example there uses that style.
This custom style was necessary back in 2010 when the gettext support
was initially added, and was subsequently documented in commit
cbcfd4e3ea ("i18n: mention "TRANSLATORS:" marker in
Documentation/CodingGuidelines", 2014-04-18).
GNU xgettext hasn't had the parsing limitation that necessitated this
exception for almost 3 years. Since its 0.19 release on 2014-06-02
it's been able to recognize TRANSLATOR comments in the standard Git
comment syntax[1].
Usually we'd like to keep compatibility with software that's that
young, but in this case literally the only person who needs to be
using a gettext newer than 3 years old is Jiang Xin (the only person
who runs & commits "make pot" results), so I think in this case we can
make an exception.
This xgettext parsing feature was added after a thread on the Git
mailing list[2] which continued on the bug-gettext[3] list, but we
never subsequently changed our style & styleguide, do so.
There are already longstanding changes in git that use the standard
comment style & have their TRANSLATORS comments extracted properly
without getting the literal "*"'s mixed up in the text, as would
happen before xgettext 0.19.
Commit 7ff2683253 ("builtin-am: implement -i/--interactive",
2015-08-04) added one such comment, which in commit df0617bfa7 ("l10n:
git.pot: v2.6.0 round 1 (123 new, 41 removed)", 2015-09-05) got picked
up in the po/git.pot file with the right format, showing that Jiang
already runs a modern xgettext.
The xgettext parser does not handle the sort of non-standard comment
style that I'm amending here in sequencer.c, but that isn't standard
Git comment syntax anyway. With this change to sequencer.c & "make
pot" the comment in the pot file is now correct:
#. TRANSLATORS: %s will be "revert", "cherry-pick" or
-#. * "rebase -i".
+#. "rebase -i".
1. http://git.savannah.gnu.org/cgit/gettext.git/commit/?id=10af7fe6bd
2. <2ce9ec406501d112e032c8208417f8100bed04c6.1397712142.git.worldhello.net@gmail.com>
(https://public-inbox.org/git/2ce9ec406501d112e032c8208417f8100bed04c6.1397712142.git.worldhello.net@gmail.com/)
3. https://lists.gnu.org/archive/html/bug-gettext/2014-04/msg00016.html
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-11 21:20:12 +00:00
|
|
|
/*
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|
* TRANSLATORS: here is a comment that explains the string to
|
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|
* be translated, that follows immediately after it.
|
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|
*/
|
2014-04-18 17:48:08 +00:00
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|
|
_("Here is a translatable string explained by the above.");
|
|
|
|
|
2007-11-08 00:33:19 +00:00
|
|
|
- Double negation is often harder to understand than no negation
|
|
|
|
at all.
|
|
|
|
|
2014-04-30 21:26:23 +00:00
|
|
|
- There are two schools of thought when it comes to comparison,
|
|
|
|
especially inside a loop. Some people prefer to have the less stable
|
|
|
|
value on the left hand side and the more stable value on the right hand
|
|
|
|
side, e.g. if you have a loop that counts variable i down to the
|
|
|
|
lower bound,
|
|
|
|
|
|
|
|
while (i > lower_bound) {
|
|
|
|
do something;
|
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|
i--;
|
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|
}
|
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|
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|
Other people prefer to have the textual order of values match the
|
|
|
|
actual order of values in their comparison, so that they can
|
|
|
|
mentally draw a number line from left to right and place these
|
|
|
|
values in order, i.e.
|
|
|
|
|
|
|
|
while (lower_bound < i) {
|
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|
do something;
|
|
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|
i--;
|
|
|
|
}
|
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|
Both are valid, and we use both. However, the more "stable" the
|
|
|
|
stable side becomes, the more we tend to prefer the former
|
|
|
|
(comparison with a constant, "i > 0", is an extreme example).
|
|
|
|
Just do not mix styles in the same part of the code and mimic
|
|
|
|
existing styles in the neighbourhood.
|
|
|
|
|
2014-05-02 20:42:39 +00:00
|
|
|
- There are two schools of thought when it comes to splitting a long
|
|
|
|
logical line into multiple lines. Some people push the second and
|
|
|
|
subsequent lines far enough to the right with tabs and align them:
|
|
|
|
|
|
|
|
if (the_beginning_of_a_very_long_expression_that_has_to ||
|
|
|
|
span_more_than_a_single_line_of ||
|
|
|
|
the_source_text) {
|
|
|
|
...
|
|
|
|
|
|
|
|
while other people prefer to align the second and the subsequent
|
|
|
|
lines with the column immediately inside the opening parenthesis,
|
|
|
|
with tabs and spaces, following our "tabstop is always a multiple
|
|
|
|
of 8" convention:
|
|
|
|
|
|
|
|
if (the_beginning_of_a_very_long_expression_that_has_to ||
|
|
|
|
span_more_than_a_single_line_of ||
|
|
|
|
the_source_text) {
|
|
|
|
...
|
|
|
|
|
|
|
|
Both are valid, and we use both. Again, just do not mix styles in
|
|
|
|
the same part of the code and mimic existing styles in the
|
|
|
|
neighbourhood.
|
|
|
|
|
|
|
|
- When splitting a long logical line, some people change line before
|
|
|
|
a binary operator, so that the result looks like a parse tree when
|
|
|
|
you turn your head 90-degrees counterclockwise:
|
|
|
|
|
|
|
|
if (the_beginning_of_a_very_long_expression_that_has_to
|
|
|
|
|| span_more_than_a_single_line_of_the_source_text) {
|
|
|
|
|
|
|
|
while other people prefer to leave the operator at the end of the
|
|
|
|
line:
|
|
|
|
|
|
|
|
if (the_beginning_of_a_very_long_expression_that_has_to ||
|
|
|
|
span_more_than_a_single_line_of_the_source_text) {
|
|
|
|
|
|
|
|
Both are valid, but we tend to use the latter more, unless the
|
|
|
|
expression gets fairly complex, in which case the former tends to
|
|
|
|
be easier to read. Again, just do not mix styles in the same part
|
|
|
|
of the code and mimic existing styles in the neighbourhood.
|
|
|
|
|
|
|
|
- When splitting a long logical line, with everything else being
|
|
|
|
equal, it is preferable to split after the operator at higher
|
|
|
|
level in the parse tree. That is, this is more preferable:
|
|
|
|
|
|
|
|
if (a_very_long_variable * that_is_used_in +
|
|
|
|
a_very_long_expression) {
|
|
|
|
...
|
|
|
|
|
|
|
|
than
|
|
|
|
|
|
|
|
if (a_very_long_variable *
|
|
|
|
that_is_used_in + a_very_long_expression) {
|
|
|
|
...
|
|
|
|
|
2007-11-08 00:33:19 +00:00
|
|
|
- Some clever tricks, like using the !! operator with arithmetic
|
|
|
|
constructs, can be extremely confusing to others. Avoid them,
|
|
|
|
unless there is a compelling reason to use them.
|
|
|
|
|
|
|
|
- Use the API. No, really. We have a strbuf (variable length
|
|
|
|
string), several arrays with the ALLOC_GROW() macro, a
|
2008-07-21 18:03:49 +00:00
|
|
|
string_list for sorted string lists, a hash map (mapping struct
|
2007-11-08 00:33:19 +00:00
|
|
|
objects) named "struct decorate", amongst other things.
|
|
|
|
|
2018-09-28 16:50:14 +00:00
|
|
|
- When you come up with an API, document its functions and structures
|
|
|
|
in the header file that exposes the API to its callers. Use what is
|
|
|
|
in "strbuf.h" as a model for the appropriate tone and level of
|
|
|
|
detail.
|
2007-11-08 00:33:19 +00:00
|
|
|
|
2015-01-15 23:20:09 +00:00
|
|
|
- The first #include in C files, except in platform specific compat/
|
|
|
|
implementations, must be either "git-compat-util.h", "cache.h" or
|
|
|
|
"builtin.h". You do not have to include more than one of these.
|
|
|
|
|
|
|
|
- A C file must directly include the header files that declare the
|
|
|
|
functions and the types it uses, except for the functions and types
|
|
|
|
that are made available to it by including one of the header files
|
|
|
|
it must include by the previous rule.
|
2007-11-08 00:33:19 +00:00
|
|
|
|
|
|
|
- If you are planning a new command, consider writing it in shell
|
|
|
|
or perl first, so that changes in semantics can be easily
|
2013-01-21 19:17:53 +00:00
|
|
|
changed and discussed. Many Git commands started out like
|
2007-11-08 00:33:19 +00:00
|
|
|
that, and a few are still scripts.
|
|
|
|
|
2013-01-21 19:17:53 +00:00
|
|
|
- Avoid introducing a new dependency into Git. This means you
|
2007-11-08 00:33:19 +00:00
|
|
|
usually should stay away from scripting languages not already
|
2013-01-21 19:17:53 +00:00
|
|
|
used in the Git core command set (unless your command is clearly
|
2007-11-08 00:33:19 +00:00
|
|
|
separate from it, such as an importer to convert random-scm-X
|
2013-01-21 19:17:53 +00:00
|
|
|
repositories to Git).
|
2009-02-09 20:54:06 +00:00
|
|
|
|
|
|
|
- When we pass <string, length> pair to functions, we should try to
|
|
|
|
pass them in that order.
|
2010-11-04 17:12:48 +00:00
|
|
|
|
i18n: add infrastructure for translating Git with gettext
Change the skeleton implementation of i18n in Git to one that can show
localized strings to users for our C, Shell and Perl programs using
either GNU libintl or the Solaris gettext implementation.
This new internationalization support is enabled by default. If
gettext isn't available, or if Git is compiled with
NO_GETTEXT=YesPlease, Git falls back on its current behavior of
showing interface messages in English. When using the autoconf script
we'll auto-detect if the gettext libraries are installed and act
appropriately.
This change is somewhat large because as well as adding a C, Shell and
Perl i18n interface we're adding a lot of tests for them, and for
those tests to work we need a skeleton PO file to actually test
translations. A minimal Icelandic translation is included for this
purpose. Icelandic includes multi-byte characters which makes it easy
to test various edge cases, and it's a language I happen to
understand.
The rest of the commit message goes into detail about various
sub-parts of this commit.
= Installation
Gettext .mo files will be installed and looked for in the standard
$(prefix)/share/locale path. GIT_TEXTDOMAINDIR can also be set to
override that, but that's only intended to be used to test Git itself.
= Perl
Perl code that's to be localized should use the new Git::I18n
module. It imports a __ function into the caller's package by default.
Instead of using the high level Locale::TextDomain interface I've
opted to use the low-level (equivalent to the C interface)
Locale::Messages module, which Locale::TextDomain itself uses.
Locale::TextDomain does a lot of redundant work we don't need, and
some of it would potentially introduce bugs. It tries to set the
$TEXTDOMAIN based on package of the caller, and has its own
hardcoded paths where it'll search for messages.
I found it easier just to completely avoid it rather than try to
circumvent its behavior. In any case, this is an issue wholly
internal Git::I18N. Its guts can be changed later if that's deemed
necessary.
See <AANLkTilYD_NyIZMyj9dHtVk-ylVBfvyxpCC7982LWnVd@mail.gmail.com> for
a further elaboration on this topic.
= Shell
Shell code that's to be localized should use the git-sh-i18n
library. It's basically just a wrapper for the system's gettext.sh.
If gettext.sh isn't available we'll fall back on gettext(1) if it's
available. The latter is available without the former on Solaris,
which has its own non-GNU gettext implementation. We also need to
emulate eval_gettext() there.
If neither are present we'll use a dumb printf(1) fall-through
wrapper.
= About libcharset.h and langinfo.h
We use libcharset to query the character set of the current locale if
it's available. I.e. we'll use it instead of nl_langinfo if
HAVE_LIBCHARSET_H is set.
The GNU gettext manual recommends using langinfo.h's
nl_langinfo(CODESET) to acquire the current character set, but on
systems that have libcharset.h's locale_charset() using the latter is
either saner, or the only option on those systems.
GNU and Solaris have a nl_langinfo(CODESET), FreeBSD can use either,
but MinGW and some others need to use libcharset.h's locale_charset()
instead.
=Credits
This patch is based on work by Jeff Epler <jepler@unpythonic.net> who
did the initial Makefile / C work, and a lot of comments from the Git
mailing list, including Jonathan Nieder, Jakub Narebski, Johannes
Sixt, Erik Faye-Lund, Peter Krefting, Junio C Hamano, Thomas Rast and
others.
[jc: squashed a small Makefile fix from Ramsay]
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-17 23:14:42 +00:00
|
|
|
- Use Git's gettext wrappers to make the user interface
|
|
|
|
translatable. See "Marking strings for translation" in po/README.
|
|
|
|
|
2018-02-08 21:38:06 +00:00
|
|
|
- Variables and functions local to a given source file should be marked
|
|
|
|
with "static". Variables that are visible to other source files
|
|
|
|
must be declared with "extern" in header files. However, function
|
|
|
|
declarations should not use "extern", as that is already the default.
|
|
|
|
|
2013-02-06 19:49:01 +00:00
|
|
|
For Perl programs:
|
|
|
|
|
|
|
|
- Most of the C guidelines above apply.
|
|
|
|
|
|
|
|
- We try to support Perl 5.8 and later ("use Perl 5.008").
|
|
|
|
|
|
|
|
- use strict and use warnings are strongly preferred.
|
|
|
|
|
|
|
|
- Don't overuse statement modifiers unless using them makes the
|
|
|
|
result easier to follow.
|
|
|
|
|
|
|
|
... do something ...
|
|
|
|
do_this() unless (condition);
|
|
|
|
... do something else ...
|
|
|
|
|
|
|
|
is more readable than:
|
|
|
|
|
|
|
|
... do something ...
|
|
|
|
unless (condition) {
|
|
|
|
do_this();
|
|
|
|
}
|
|
|
|
... do something else ...
|
|
|
|
|
|
|
|
*only* when the condition is so rare that do_this() will be almost
|
|
|
|
always called.
|
|
|
|
|
|
|
|
- We try to avoid assignments inside "if ()" conditions.
|
|
|
|
|
|
|
|
- Learn and use Git.pm if you need that functionality.
|
|
|
|
|
|
|
|
- For Emacs, it's useful to put the following in
|
|
|
|
GIT_CHECKOUT/.dir-locals.el, assuming you use cperl-mode:
|
|
|
|
|
|
|
|
;; note the first part is useful for C editing, too
|
|
|
|
((nil . ((indent-tabs-mode . t)
|
|
|
|
(tab-width . 8)
|
|
|
|
(fill-column . 80)))
|
|
|
|
(cperl-mode . ((cperl-indent-level . 8)
|
|
|
|
(cperl-extra-newline-before-brace . nil)
|
|
|
|
(cperl-merge-trailing-else . t))))
|
|
|
|
|
2013-01-30 20:47:32 +00:00
|
|
|
For Python scripts:
|
|
|
|
|
|
|
|
- We follow PEP-8 (http://www.python.org/dev/peps/pep-0008/).
|
|
|
|
|
|
|
|
- As a minimum, we aim to be compatible with Python 2.6 and 2.7.
|
|
|
|
|
|
|
|
- Where required libraries do not restrict us to Python 2, we try to
|
|
|
|
also be compatible with Python 3.1 and later.
|
|
|
|
|
|
|
|
- When you must differentiate between Unicode literals and byte string
|
|
|
|
literals, it is OK to use the 'b' prefix. Even though the Python
|
|
|
|
documentation for version 2.6 does not mention this prefix, it has
|
|
|
|
been supported since version 2.6.0.
|
|
|
|
|
2014-06-16 12:55:57 +00:00
|
|
|
Error Messages
|
|
|
|
|
|
|
|
- Do not end error messages with a full stop.
|
|
|
|
|
|
|
|
- Do not capitalize ("unable to open %s", not "Unable to open %s")
|
|
|
|
|
|
|
|
- Say what the error is first ("cannot open %s", not "%s: cannot open")
|
|
|
|
|
|
|
|
|
2015-01-27 20:26:03 +00:00
|
|
|
Externally Visible Names
|
|
|
|
|
|
|
|
- For configuration variable names, follow the existing convention:
|
|
|
|
|
|
|
|
. The section name indicates the affected subsystem.
|
|
|
|
|
|
|
|
. The subsection name, if any, indicates which of an unbounded set
|
|
|
|
of things to set the value for.
|
|
|
|
|
|
|
|
. The variable name describes the effect of tweaking this knob.
|
|
|
|
|
|
|
|
The section and variable names that consist of multiple words are
|
|
|
|
formed by concatenating the words without punctuations (e.g. `-`),
|
|
|
|
and are broken using bumpyCaps in documentation as a hint to the
|
|
|
|
reader.
|
|
|
|
|
|
|
|
When choosing the variable namespace, do not use variable name for
|
|
|
|
specifying possibly unbounded set of things, most notably anything
|
|
|
|
an end user can freely come up with (e.g. branch names). Instead,
|
|
|
|
use subsection names or variable values, like the existing variable
|
|
|
|
branch.<name>.description does.
|
|
|
|
|
|
|
|
|
2010-11-04 17:12:48 +00:00
|
|
|
Writing Documentation:
|
|
|
|
|
2013-05-07 17:39:46 +00:00
|
|
|
Most (if not all) of the documentation pages are written in the
|
|
|
|
AsciiDoc format in *.txt files (e.g. Documentation/git.txt), and
|
|
|
|
processed into HTML and manpages (e.g. git.html and git.1 in the
|
|
|
|
same directory).
|
2013-03-21 21:17:32 +00:00
|
|
|
|
2013-08-01 18:49:54 +00:00
|
|
|
The documentation liberally mixes US and UK English (en_US/UK)
|
|
|
|
norms for spelling and grammar, which is somewhat unfortunate.
|
|
|
|
In an ideal world, it would have been better if it consistently
|
|
|
|
used only one and not the other, and we would have picked en_US
|
|
|
|
(if you wish to correct the English of some of the existing
|
|
|
|
documentation, please see the documentation-related advice in the
|
|
|
|
Documentation/SubmittingPatches file).
|
|
|
|
|
2010-11-04 17:12:48 +00:00
|
|
|
Every user-visible change should be reflected in the documentation.
|
|
|
|
The same general rule as for code applies -- imitate the existing
|
2013-11-14 23:08:45 +00:00
|
|
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conventions.
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A few commented examples follow to provide reference when writing or
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modifying command usage strings and synopsis sections in the manual
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pages:
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2010-11-04 17:12:48 +00:00
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2011-02-15 19:02:56 +00:00
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Placeholders are spelled in lowercase and enclosed in angle brackets:
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2010-11-04 17:12:48 +00:00
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<file>
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--sort=<key>
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--abbrev[=<n>]
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2015-01-13 07:44:47 +00:00
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If a placeholder has multiple words, they are separated by dashes:
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<new-branch-name>
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--template=<template-directory>
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2011-01-03 19:03:34 +00:00
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Possibility of multiple occurrences is indicated by three dots:
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2010-11-04 17:12:48 +00:00
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<file>...
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(One or more of <file>.)
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Optional parts are enclosed in square brackets:
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[<extra>]
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(Zero or one <extra>.)
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--exec-path[=<path>]
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(Option with an optional argument. Note that the "=" is inside the
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brackets.)
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[<patch>...]
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(Zero or more of <patch>. Note that the dots are inside, not
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outside the brackets.)
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2015-01-13 07:44:47 +00:00
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Multiple alternatives are indicated with vertical bars:
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2010-11-04 17:12:48 +00:00
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[-q | --quiet]
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[--utf8 | --no-utf8]
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Parentheses are used for grouping:
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2015-01-13 07:44:47 +00:00
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[(<rev> | <range>)...]
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2010-11-04 17:12:48 +00:00
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(Any number of either <rev> or <range>. Parens are needed to make
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it clear that "..." pertains to both <rev> and <range>.)
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[(-p <parent>)...]
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(Any number of option -p, each with one <parent> argument.)
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git remote set-head <name> (-a | -d | <branch>)
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(One and only one of "-a", "-d" or "<branch>" _must_ (no square
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brackets) be provided.)
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And a somewhat more contrived example:
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--diff-filter=[(A|C|D|M|R|T|U|X|B)...[*]]
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Here "=" is outside the brackets, because "--diff-filter=" is a
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valid usage. "*" has its own pair of brackets, because it can
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(optionally) be specified only when one or more of the letters is
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also provided.
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2013-01-21 19:16:20 +00:00
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A note on notation:
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Use 'git' (all lowercase) when talking about commands i.e. something
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the user would type into a shell and use 'Git' (uppercase first letter)
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when talking about the version control system and its properties.
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2013-11-14 23:08:45 +00:00
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A few commented examples follow to provide reference when writing or
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modifying paragraphs or option/command explanations that contain options
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or commands:
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2016-06-07 22:35:05 +00:00
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Literal examples (e.g. use of command-line options, command names,
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2019-03-06 13:04:45 +00:00
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branch names, URLs, pathnames (files and directories), configuration and
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environment variables) must be typeset in monospace (i.e. wrapped with
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backticks):
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2013-11-14 23:08:45 +00:00
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`--pretty=oneline`
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`git rev-list`
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2015-03-11 20:32:45 +00:00
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`remote.pushDefault`
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2019-03-06 13:04:45 +00:00
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`http://git.example.com`
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`.git/config`
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2016-06-07 22:35:05 +00:00
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`GIT_DIR`
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2016-06-28 11:40:14 +00:00
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`HEAD`
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2016-06-07 22:35:05 +00:00
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An environment variable must be prefixed with "$" only when referring to its
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value and not when referring to the variable itself, in this case there is
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nothing to add except the backticks:
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`GIT_DIR` is specified
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`$GIT_DIR/hooks/pre-receive`
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2013-11-14 23:08:45 +00:00
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Word phrases enclosed in `backtick characters` are rendered literally
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and will not be further expanded. The use of `backticks` to achieve the
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previous rule means that literal examples should not use AsciiDoc
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escapes.
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Correct:
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`--pretty=oneline`
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Incorrect:
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`\--pretty=oneline`
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If some place in the documentation needs to typeset a command usage
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example with inline substitutions, it is fine to use +monospaced and
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inline substituted text+ instead of `monospaced literal text`, and with
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the former, the part that should not get substituted must be
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quoted/escaped.
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