5 \___|\___/|_| \_\_____|
7 When Contributing Source Code
9 This document is intended to offer guidelines that can be useful to keep in
10 mind when you decide to contribute to the project. This concerns new features
11 as well as corrections to existing flaws or bugs.
14 1.1 Join the Community
18 2. cURL Coding Standards
24 2.6 Non-clobbering All Over
25 2.7 Platform Dependent Code
26 2.8 Write Separate Patches
27 2.9 Patch Against Recent Sources
31 3. Pushing Out Your Changes
32 3.1 Write Access to git Repository
33 3.2 How To Make a Patch with git
34 3.3 How To Make a Patch without git
35 3.4 How to get your changes into the main sources
36 3.5 Write good commit messages
37 3.6 About pull requests
39 ==============================================================================
43 1.1 Join the Community
45 Skip over to http://curl.haxx.se/mail/ and join the appropriate mailing
46 list(s). Read up on details before you post questions. Read this file before
47 you start sending patches! We prefer patches and discussions being held on
48 the mailing list(s), not sent to individuals.
50 Before posting to one of the curl mailing lists, please read up on the mailing
51 list etiquette: http://curl.haxx.se/mail/etiquette.html
53 We also hang out on IRC in #curl on irc.freenode.net
55 If you're at all interested in the code side of things, consider clicking
56 'watch' on the curl repo at github to get notified on pull requests and new
61 When contributing with code, you agree to put your changes and new code under
62 the same license curl and libcurl is already using unless stated and agreed
65 If you add a larger piece of code, you can opt to make that file or set of
66 files to use a different license as long as they don't enforce any changes to
67 the rest of the package and they make sense. Such "separate parts" can not be
68 GPL licensed (as we don't want copyleft to affect users of libcurl) but they
69 must use "GPL compatible" licenses (as we want to allow users to use libcurl
70 properly in GPL licensed environments).
72 When changing existing source code, you do not alter the copyright of the
73 original file(s). The copyright will still be owned by the original
74 creator(s) or those who have been assigned copyright by the original
77 By submitting a patch to the curl project, you are assumed to have the right
78 to the code and to be allowed by your employer or whatever to hand over that
79 patch/code to us. We will credit you for your changes as far as possible, to
80 give credit but also to keep a trace back to who made what changes. Please
81 always provide us with your full real name when contributing!
85 Source code, the man pages, the INTERNALS document, TODO, KNOWN_BUGS and the
86 most recent changes in the git log. Just lurking on the curl-library mailing
87 list is gonna give you a lot of insights on what's going on right now. Asking
88 there is a good idea too.
90 2. cURL Coding Standards
94 Try using a non-confusing naming scheme for your new functions and variable
95 names. It doesn't necessarily have to mean that you should use the same as in
96 other places of the code, just that the names should be logical,
97 understandable and be named according to what they're used for. File-local
98 functions should be made static. We like lower case names.
100 See the INTERNALS document on how we name non-exported library-global
105 Use the same indenting levels and bracing method as all the other code
106 already does. It makes the source code easier to follow if all of it is
107 written using the same style. We don't ask you to like it, we just ask you to
108 follow the tradition! ;-) This mainly means: 2-level indents, using spaces
109 only (no tabs) and having the opening brace ({) on the same line as the if()
112 Also note that we use if() and while() with no space before the parenthesis.
116 Comment your source code extensively using C comments (/* comment */), DO NOT
117 use C++ comments (// this style). Commented code is quality code and enables
118 future modifications much more. Uncommented code risk having to be completely
119 replaced when someone wants to extend things, since other persons' source
120 code can get quite hard to read.
124 We write source lines shorter than 80 columns.
128 Keep your functions small. If they're small you avoid a lot of mistakes and
129 you don't accidentally mix up variables etc.
131 2.6 Non-clobbering All Over
133 When you write new functionality or fix bugs, it is important that you don't
134 fiddle all over the source files and functions. Remember that it is likely
135 that other people have done changes in the same source files as you have and
136 possibly even in the same functions. If you bring completely new
137 functionality, try writing it in a new source file. If you fix bugs, try to
138 fix one bug at a time and send them as separate patches.
140 2.7 Platform Dependent Code
142 Use #ifdef HAVE_FEATURE to do conditional code. We avoid checking for
143 particular operating systems or hardware in the #ifdef lines. The
144 HAVE_FEATURE shall be generated by the configure script for unix-like systems
145 and they are hard-coded in the config-[system].h files for the others.
147 2.8 Write Separate Patches
149 It is annoying when you get a huge patch from someone that is said to fix 511
150 odd problems, but discussions and opinions don't agree with 510 of them - or
151 509 of them were already fixed in a different way. Then the patcher needs to
152 extract the single interesting patch from somewhere within the huge pile of
153 source, and that gives a lot of extra work. Preferably, all fixes that
154 correct different problems should be in their own patch with an attached
155 description exactly what they correct so that all patches can be selectively
156 applied by the maintainer or other interested parties.
158 Also, separate patches enable bisecting much better when we track problems in
161 2.9 Patch Against Recent Sources
163 Please try to get the latest available sources to make your patches
164 against. It makes the life of the developers so much easier. The very best is
165 if you get the most up-to-date sources from the git repository, but the
166 latest release archive is quite OK as well!
170 Writing docs is dead boring and one of the big problems with many open source
171 projects. Someone's gotta do it. It makes it a lot easier if you submit a
172 small description of your fix or your new features with every contribution so
173 that it can be swiftly added to the package documentation.
175 The documentation is always made in man pages (nroff formatted) or plain
176 ASCII files. All HTML files on the web site and in the release archives are
177 generated from the nroff/ASCII versions.
181 Since the introduction of the test suite, we can quickly verify that the main
182 features are working as they're supposed to. To maintain this situation and
183 improve it, all new features and functions that are added need to be tested
184 in the test suite. Every feature that is added should get at least one valid
185 test case that verifies that it works as documented. If every submitter also
186 posts a few test cases, it won't end up as a heavy burden on a single person!
188 If you don't have test cases or perhaps you have done something that is very
189 hard to write tests for, do explain exactly how you have otherwise tested and
190 verified your changes.
192 3. Pushing Out Your Changes
194 3.1 Write Access to git Repository
196 If you are a frequent contributor, or have another good reason, you can of
197 course get write access to the git repository and then you'll be able to push
198 your changes straight into the git repo instead of sending changes by mail as
199 patches. Just ask if this is what you'd want. You will be required to have
200 posted a few quality patches first, before you can be granted push access.
202 3.2 How To Make a Patch with git
204 You need to first checkout the repository:
206 git clone https://github.com/bagder/curl.git
208 You then proceed and edit all the files you like and you commit them to your
213 As usual, group your commits so that you commit all changes that at once that
214 constitutes a logical change. See also section "3.5 Write good commit
217 Once you have done all your commits and you're happy with what you see, you
218 can make patches out of your changes that are suitable for mailing:
220 git format-patch remotes/origin/master
222 This creates files in your local directory named NNNN-[name].patch for each
225 Now send those patches off to the curl-library list. You can of course opt to
226 do that with the 'git send-email' command.
228 3.3 How To Make a Patch without git
230 Keep a copy of the unmodified curl sources. Make your changes in a separate
231 source tree. When you think you have something that you want to offer the
232 curl community, use GNU diff to generate patches.
234 If you have modified a single file, try something like:
236 diff -u unmodified-file.c my-changed-one.c > my-fixes.diff
238 If you have modified several files, possibly in different directories, you
239 can use diff recursively:
241 diff -ur curl-original-dir curl-modified-sources-dir > my-fixes.diff
243 The GNU diff and GNU patch tools exist for virtually all platforms, including
244 all kinds of Unixes and Windows:
246 For unix-like operating systems:
248 https://savannah.gnu.org/projects/patch/
249 https://www.gnu.org/software/diffutils/
253 http://gnuwin32.sourceforge.net/packages/patch.htm
254 http://gnuwin32.sourceforge.net/packages/diffutils.htm
256 3.4 How to get your changes into the main sources
258 Submit your patch to the curl-library mailing list.
260 Make the patch against as recent sources as possible.
262 Make sure your patch adheres to the source indent and coding style of already
263 existing source code. Failing to do so just adds more work for me.
265 Respond to replies on the list about the patch and answer questions and/or
266 fix nits/flaws. This is very important. I will take lack of replies as a sign
267 that you're not very anxious to get your patch accepted and I tend to simply
268 drop such patches from my TODO list.
270 If you've followed the above paragraphs and your patch still hasn't been
271 incorporated after some weeks, consider resubmitting it to the list.
273 3.5 Write good commit messages
275 A short guide to how to do fine commit messages in the curl project.
278 [area]: [short line describing the main effect]
280 [separate the above single line from the rest with an empty line]
282 [full description, no wider than 72 columns that describe as much as
283 possible as to why this change is made, and possibly what things
284 it fixes and everything else that is related]
286 [Bug: link to source of the report or more related discussion]
287 [Reported-by: John Doe - credit the reporter]
288 [whatever-else-by: credit all helpers, finders, doers]
291 Don't forget to use commit --author="" if you commit someone else's work,
292 and make sure that you have your own user and email setup correctly in git
295 3.6 About pull requests
297 With git (and especially github) it is easy and tempting to send a pull
298 request to the curl project to have changes merged this way instead of
299 mailing patches to the curl-library mailing list.
301 We used to dislike this but we're trying to change that and accept that this
302 is a frictionless way for people to contribute to the project. We now welcome
305 We will continue to avoid using github's merge tools to make the history
306 linear and to make sure commits follow our style guidelines.