Signed-off-by: Wen Liang <liangwen12year@gmail.com> https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/792
9 KiB
Guidelines for Contributing
Community
Check out website https://networkmanager.dev and our GNOME page.
The release tarballs can be found at download.gnome.org.
Our mailing list is networkmanager-list@gnome.org (archive).
Find us on IRC channel #nm
on freenode.
Report issues and send patches via gitlab.freedesktop.org or our mailing list.
Legal
NetworkManager is partly licensed under terms of GNU Lesser General Public License version 2 or later (LGPL-2.1-or-later). That is for example the case for libnm. For historical reasons, the daemon itself is licensed under terms of GNU General Public License, version 2 or later (GPL-2.0-or-later). See the SPDX license comment in the source files.
Note that all new contributions to NetworkManager MUST be made under terms of LGPL-2.1-or-later, that is also the case for files that are currently licensed GPL-2.0-or-later. The reason is that we might one day use the code under terms of LGPL-2.1-or-later and all new contributions already must already agree to that. For more details see RELICENSE.md.
Coding Standard
The formatting uses clang-format with clang 11.0. Run
./contrib/scripts/nm-code-format.sh -i
to reformat the code
or call clang-format
yourself.
You may also call ./contrib/scripts/nm-code-format-container.sh
which runs a Fedora 33 container using podman.
You are welcome to not bother and open a merge request with
wrong formatting, but note that we then will automatically adjust
your contribution before merging.
The automatic reformatting was done by commit 328fb90f3e
.
Use --ignore-rev
option or --ignore-revs-file .git-blame-ignore-revs
to ignore
the reformatting commit with git-blame:
$ git config --add 'blame.ignoreRevsFile' '.git-blame-ignore-revs'
Since our coding style is entirely automated, the following are just some details of the style we use:
-
Indent with 4 spaces. (no tabs).
-
Have no space between the function name and the opening '('.
- GOOD:
g_strdup(x)
- BAD:
g_strdup (x)
- GOOD:
-
C-style comments
- GOOD:
f(x); /* comment */
- BAD:
f(x); // comment
- GOOD:
-
Keep assignments in the variable declaration area pretty short.
- GOOD:
MyObject *object;
- BAD:
MyObject *object = complex_and_long_init_function(arg1, arg2, arg3);
- GOOD:
-
80-cols is a guideline, don't make the code uncomfortable in order to fit in less than 80 cols.
-
Constants are CAPS_WITH_UNDERSCORES and use the preprocessor.
- GOOD:
#define MY_CONSTANT 42
- BAD:
static const unsigned myConstant = 42;
- GOOD:
Assertions in NetworkManager code
There are different kind of assertions. Use the one that is appropriate.
-
g_return_*()
from glib. This is usually enabled in release builds and can be disabled withG_DISABLE_CHECKS
define. This usesg_log()
withG_LOG_LEVEL_CRITICAL
level (which allows the program to continue, unlessG_DEBUG=fatal-criticals
orG_DEBUG=fatal-warnings
is set). As such, this is usually the preferred way for assertions that are supposed to be enabled by default.
Optimally, after ag_return_*()
failure the program can still continue. This is also the reason whyg_return_*()
is preferable overg_assert()
. For example, that is often not the case for functions that return aGError
, becauseg_return_*()
will return failure without setting the error output. That often leads to a crash immediately after, because the caller requires theGError
to be set. Make a reasonable effort so that an assertion failure may allow the process to proceed. But don't put too much effort in it. After all, it's an assertion failure that is not supposed to happen either way. -
nm_assert()
from NetworkManager. This is disabled by default in release builds, but enabled if you build--with-more-assertions
. See theWITH_MORE_ASSERTS
define. This is preferred for assertions that are expensive to check or nor necessary to check frequently. It's also for conditions that can easily be verified to be true and where future refactoring is unlikely to break the invariant. Use such asserts deliberately and assume they are removed from production builds. -
g_assert()
from glib. This is used in unit tests and commonly enabled in release builds. It can be disabled withG_DISABLE_ASSERT
define. Since such an assertion failure results in a hard crash, you should almost always preferg_return_*()
overg_assert()
(except in unit tests). -
assert()
from C89's<assert.h>
. It is usually enabled in release builds and can be disabled withNDEBUG
define. Don't use it in NetworkManager, it's basically like g_assert(). -
g_log()
from glib. These are always compiled in, depending on the logging level they act as assertions too.G_LOG_LEVEL_ERROR
messages abort the program,G_LOG_LEVEL_CRITICAL
log a critical warning (likeg_return_*()
, seeG_DEBUG=fatal-criticals
) andG_LOG_LEVEL_WARNING
logs a warning (seeG_DEBUG=fatal-warnings
).G_LOG_LEVEL_DEBUG
level is usually not printed, unlessG_MESSAGES_DEBUG
environment variable enables it.
In general, avoid usingg_log()
in NetworkManager. We have nm-logging instead which logs to syslog or systemd-journald. From a library like libnm it might make sense to log warnings (if something is really wrong) or debug messages. But better don't. If it's important, find a way to report the condition via the API to the caller. If it's not important, keep silent. In particular, don't use levelsG_LOG_LEVEL_CRITICAL
andG_LOG_LEVEL_WARNING
because we treat them as assertions and we want to run all out tests withG_DEBUG=fatal-warnings
. -
g_warn_if_*()
from glib. These are always compiled in and log aG_LOG_LEVEL_WARNING
warning. Don't use this. -
G_TYPE_CHECK_INSTANCE_CAST()
from glib. Unless building withWITH_MORE_ASSERTS
, we setG_DISABLE_CAST_CHECKS
. This means, cast macros likeNM_DEVICE(ptr)
translate to plain C pointer casts. Use such cast macros deliberately, in production code they are cheap, with more asserts enabled they check that the pointer type is suitable.
Of course, every assertion failure is a bug, and calling it must have no side effects.
Theoretically, you are welcome to set G_DISABLE_CHECKS
, G_DISABLE_ASSERT
and
NDEBUG
in production builds. In practice, nobody tests such a configuration, so beware.
For testing, you also want to run NetworkManager with environment variable
G_DEBUG=fatal-warnings
to crash upon G_LOG_LEVEL_CRITICAL
and G_LOG_LEVEL_WARNING
g_log()
message. NetworkManager won't use these levels for regular logging
but for assertions.
Git Notes (refs/notes/bugs)
We use special tags in commit messages like "Fixes", "cherry picked from" and "Ignore-Backport".
The find-backports script uses these to find patches that
should be backported to older branches. Sometimes we don't know a-priory to mark a commit
with these tags so we can instead use the bugs
notes.
The git notes reference is called "refs/notes/bugs".
So configure:
$ git config --add 'remote.origin.fetch' 'refs/notes/bugs:refs/notes/bugs'
$ git config --add 'notes.displayref' 'refs/notes/bugs'
For example, set notes with
$ git notes --ref refs/notes/bugs add -m "(cherry picked from $COMMIT_SHA)" HEAD
You should see the notes in git-log output as well.
To resync our local notes use:
$ git fetch origin refs/notes/bugs:refs/notes/bugs -f
Code Structure
./contrib
- Contains a lot of required package, configuration for different platform and environment, build NM from source tree.
./data
- Contains some configurations and rules.
./docs
- Contains the generated documentation for libnm and for the D-Bus API.
./examples
- Some code examples for basic networking operations and status checking.
./introspection
- XML docs describing various D-Bus interface and their properties.
./m4
- Contains M4 macros source files for autoconf.
./man
- NM manual files.
./po
- contains text-based portable object file. These .PO files are referenced by GNU gettext as a property file and these files are human readable used for translating purpose.
./src
- source code for libnm, nmcli, nm-cloud-setup, nmtui…
./tools
- tools for generating the intermediate files or merging the file.
Cscope/ctags
NetworkManager's source code is large. It may be a good idea to use tools like cscope/ctags to index the
source code and navigate it. These tools can integrate with editors like Vim
and Emacs
. See: