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 Please don't send 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
57 When contributing with code, you agree to put your changes and new code under
58 the same license curl and libcurl is already using unless stated and agreed
61 If you add a larger piece of code, you can opt to make that file or set of
62 files to use a different license as long as they don't enforce any changes to
63 the rest of the package and they make sense. Such "separate parts" can not be
64 GPL licensed (as we don't want copyleft to affect users of libcurl) but they
65 must use "GPL compatible" licenses (as we want to allow users to use libcurl
66 properly in GPL licensed environments).
68 When changing existing source code, you do not alter the copyright of the
69 original file(s). The copyright will still be owned by the original
70 creator(s) or those who have been assigned copyright by the original
73 By submitting a patch to the curl project, you are assumed to have the right
74 to the code and to be allowed by your employer or whatever to hand over that
75 patch/code to us. We will credit you for your changes as far as possible, to
76 give credit but also to keep a trace back to who made what changes. Please
77 always provide us with your full real name when contributing!
81 Source code, the man pages, the INTERNALS document, TODO, KNOWN_BUGS, the
82 most recent CHANGES. Just lurking on the curl-library mailing list is gonna
83 give you a lot of insights on what's going on right now. Asking there is a
86 2. cURL Coding Standards
90 Try using a non-confusing naming scheme for your new functions and variable
91 names. It doesn't necessarily have to mean that you should use the same as in
92 other places of the code, just that the names should be logical,
93 understandable and be named according to what they're used for. File-local
94 functions should be made static. We like lower case names.
96 See the INTERNALS document on how we name non-exported library-global
101 Use the same indenting levels and bracing method as all the other code
102 already does. It makes the source code easier to follow if all of it is
103 written using the same style. We don't ask you to like it, we just ask you to
104 follow the tradition! ;-) This mainly means: 2-level indents, using spaces
105 only (no tabs) and having the opening brace ({) on the same line as the if()
108 Also note that we use if() and while() with no space before the parenthesis.
112 Comment your source code extensively using C comments (/* comment */), DO NOT
113 use C++ comments (// this style). Commented code is quality code and enables
114 future modifications much more. Uncommented code risk having to be completely
115 replaced when someone wants to extend things, since other persons' source
116 code can get quite hard to read.
120 We write source lines shorter than 80 columns.
124 Keep your functions small. If they're small you avoid a lot of mistakes and
125 you don't accidentally mix up variables etc.
127 2.6 Non-clobbering All Over
129 When you write new functionality or fix bugs, it is important that you don't
130 fiddle all over the source files and functions. Remember that it is likely
131 that other people have done changes in the same source files as you have and
132 possibly even in the same functions. If you bring completely new
133 functionality, try writing it in a new source file. If you fix bugs, try to
134 fix one bug at a time and send them as separate patches.
136 2.7 Platform Dependent Code
138 Use #ifdef HAVE_FEATURE to do conditional code. We avoid checking for
139 particular operating systems or hardware in the #ifdef lines. The
140 HAVE_FEATURE shall be generated by the configure script for unix-like systems
141 and they are hard-coded in the config-[system].h files for the others.
143 2.8 Write Separate Patches
145 It is annoying when you get a huge patch from someone that is said to fix 511
146 odd problems, but discussions and opinions don't agree with 510 of them - or
147 509 of them were already fixed in a different way. Then the patcher needs to
148 extract the single interesting patch from somewhere within the huge pile of
149 source, and that gives a lot of extra work. Preferably, all fixes that
150 correct different problems should be in their own patch with an attached
151 description exactly what they correct so that all patches can be selectively
152 applied by the maintainer or other interested parties.
154 Also, separate patches enable bisecting much better when we track problems in
157 2.9 Patch Against Recent Sources
159 Please try to get the latest available sources to make your patches
160 against. It makes the life of the developers so much easier. The very best is
161 if you get the most up-to-date sources from the git repository, but the
162 latest release archive is quite OK as well!
166 Writing docs is dead boring and one of the big problems with many open source
167 projects. Someone's gotta do it. It makes it a lot easier if you submit a
168 small description of your fix or your new features with every contribution so
169 that it can be swiftly added to the package documentation.
171 The documentation is always made in man pages (nroff formatted) or plain
172 ASCII files. All HTML files on the web site and in the release archives are
173 generated from the nroff/ASCII versions.
177 Since the introduction of the test suite, we can quickly verify that the main
178 features are working as they're supposed to. To maintain this situation and
179 improve it, all new features and functions that are added need to be tested
180 in the test suite. Every feature that is added should get at least one valid
181 test case that verifies that it works as documented. If every submitter also
182 posts a few test cases, it won't end up as a heavy burden on a single person!
184 If you don't have test cases or perhaps you have done something that is very
185 hard to write tests for, do explain exactly how you have otherwise tested and
186 verified your changes.
188 3. Pushing Out Your Changes
190 3.1 Write Access to git Repository
192 If you are a frequent contributor, or have another good reason, you can of
193 course get write access to the git repository and then you'll be able to push
194 your changes straight into the git repo instead of sending changes by mail as
195 patches. Just ask if this is what you'd want. You will be required to have
196 posted a few quality patches first, before you can be granted push access.
198 3.2 How To Make a Patch with git
200 You need to first checkout the repository:
202 git clone git://github.com/bagder/curl.git
204 You then proceed and edit all the files you like and you commit them to your
209 As usual, group your commits so that you commit all changes that at once that
210 constitutes a logical change. See also section "3.5 Write good commit
213 Once you have done all your commits and you're happy with what you see, you
214 can make patches out of your changes that are suitable for mailing:
216 git format-patch remotes/origin/master
218 This creates files in your local directory named NNNN-[name].patch for each
221 Now send those patches off to the curl-library list. You can of course opt to
222 do that with the 'git send-email' command.
224 3.3 How To Make a Patch without git
226 Keep a copy of the unmodified curl sources. Make your changes in a separate
227 source tree. When you think you have something that you want to offer the
228 curl community, use GNU diff to generate patches.
230 If you have modified a single file, try something like:
232 diff -u unmodified-file.c my-changed-one.c > my-fixes.diff
234 If you have modified several files, possibly in different directories, you
235 can use diff recursively:
237 diff -ur curl-original-dir curl-modified-sources-dir > my-fixes.diff
239 The GNU diff and GNU patch tools exist for virtually all platforms, including
240 all kinds of Unixes and Windows:
242 For unix-like operating systems:
244 http://www.gnu.org/software/patch/patch.html
245 http://www.gnu.org/directory/diffutils.html
249 http://gnuwin32.sourceforge.net/packages/patch.htm
250 http://gnuwin32.sourceforge.net/packages/diffutils.htm
252 3.4 How to get your changes into the main sources
254 Submit your patch to the curl-library mailing list.
256 Make the patch against as recent sources as possible.
258 Make sure your patch adheres to the source indent and coding style of already
259 existing source code. Failing to do so just adds more work for me.
261 Respond to replies on the list about the patch and answer questions and/or
262 fix nits/flaws. This is very important. I will take lack of replies as a sign
263 that you're not very anxious to get your patch accepted and I tend to simply
264 drop such patches from my TODO list.
266 If you've followed the above paragraphs and your patch still hasn't been
267 incorporated after some weeks, consider resubmitting it to the list.
269 3.5 Write good commit messages
271 A short guide to how to do fine commit messages in the curl project.
274 [area]: [short line describing the main effect]
276 [separate the above single line from the rest with an empty line]
278 [full description, no wider than 72 columns that describe as much as
279 possible as to why this change is made, and possibly what things
280 it fixes and everything else that is related]
282 [Bug: link to source of the report or more related discussion]
283 [Reported-by: John Doe - credit the reporter]
284 [whatever-else-by: credit all helpers, finders, doers]
287 Don't forget to use commit --author="" if you commit someone else's work,
288 and make sure that you have your own user and email setup correctly in git
291 3.6 Please don't send pull requests
293 With git (and especially github) it is easy and tempting to send a pull
294 request to one or more people in the curl project to have changes merged this
295 way instead of mailing patches to the curl-library mailing list.
297 We don't like that. We want them mailed for these reasons:
299 - Peer review. Anyone and everyone on the list can review, comment and
300 improve on the patch. Pull requests limit this ability.
302 - Anyone can merge the patch into their own trees for testing and those who
303 have push rights can push it to the main repo. It doesn't have to be anyone
304 the patch author knows beforehand.
306 - Commit messages can be tweaked and changed if merged locally instead of
307 using github. Merges directly on github requires the changes to be perfect
308 already, which they seldom are.
310 - Merges on github prevents rebases and even enforces --no-ff which is a git
311 style we don't otherwise use in the project
313 However: once patches have been reviewed and deemed fine on list they are
314 perfectly OK to be pulled from a published git tree.