Like other projects, we also have some guidelines to keep to the
-code. For Git in general, three rough rules are:
+code. For Git in general, a few rough rules are:
- Most importantly, we never say "It's in POSIX; we'll happily
ignore your needs should your system not conform to it."
"Once it _is_ in the tree, it's not really worth the patch noise to
go and fix it up."
- Cf. http://article.gmane.org/gmane.linux.kernel/943020
+ Cf. http://lkml.iu.edu/hypermail/linux/kernel/1001.3/01069.html
Make your code readable and sensible, and don't try to be clever.
- We try to keep to at most 80 characters per line.
+ - 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".
+
- We try to support a wide range of C compilers to compile Git with,
including old ones. That means that you should not use C99
initializers, even if a lot of compilers grok it.
x = 1;
}
- is frowned upon. A gray area is when the statement extends
- over a few lines, and/or you have a lengthy comment atop of
- it. Also, like in the Linux kernel, if there is a long list
- of "else if" statements, it can make sense to add braces to
- single line blocks.
+ 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();
+ }
- We try to avoid assignments in the condition of an "if" statement.
Note however that a comment that explains a translatable string to
translators uses a convention of starting with a magic token
- "TRANSLATORS: " immediately after the opening delimiter, even when
- it spans multiple lines. We do not add an asterisk at the beginning
- of each line, either. E.g.
+ "TRANSLATORS: ", e.g.
- /* TRANSLATORS: here is a comment that explains the string
- to be translated, that follows immediately after it */
+ /*
+ * TRANSLATORS: here is a comment that explains the string to
+ * be translated, that follows immediately after it.
+ */
_("Here is a translatable string explained by the above.");
- Double negation is often harder to understand than no negation
- When you come up with an API, document it.
- - The first #include in C files, except in platform specific
- compat/ implementations, should be git-compat-util.h or another
- header file that includes it, such as cache.h or builtin.h.
+ - 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.
- If you are planning a new command, consider writing it in shell
or perl first, so that changes in semantics can be easily
documentation for version 2.6 does not mention this prefix, it has
been supported since version 2.6.0.
+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")
+
+
+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.
+
+
Writing Documentation:
Most (if not all) of the documentation pages are written in the
--sort=<key>
--abbrev[=<n>]
+ If a placeholder has multiple words, they are separated by dashes:
+ <new-branch-name>
+ --template=<template-directory>
+
Possibility of multiple occurrences is indicated by three dots:
<file>...
(One or more of <file>.)
(Zero or more of <patch>. Note that the dots are inside, not
outside the brackets.)
- Multiple alternatives are indicated with vertical bar:
+ Multiple alternatives are indicated with vertical bars:
[-q | --quiet]
[--utf8 | --no-utf8]
Parentheses are used for grouping:
- [(<rev>|<range>)...]
+ [(<rev> | <range>)...]
(Any number of either <rev> or <range>. Parens are needed to make
it clear that "..." pertains to both <rev> and <range>.)
modifying paragraphs or option/command explanations that contain options
or commands:
- Literal examples (e.g. use of command-line options, command names, and
- configuration variables) are typeset in monospace, and if you can use
- `backticks around word phrases`, do so.
+ Literal examples (e.g. use of command-line options, command names,
+ branch names, configuration and environment variables) must be
+ typeset in monospace (i.e. wrapped with backticks):
`--pretty=oneline`
`git rev-list`
- `remote.pushdefault`
+ `remote.pushDefault`
+ `GIT_DIR`
+ `HEAD`
+
+ An environment variable must be prefixed with "$" only when referring to its
+ value and not when referring to the variable itself, in this case there is
+ nothing to add except the backticks:
+ `GIT_DIR` is specified
+ `$GIT_DIR/hooks/pre-receive`
Word phrases enclosed in `backtick characters` are rendered literally
and will not be further expanded. The use of `backticks` to achieve the