1 _ _ ____ _ 2 ___| | | | _ \| | 3 / __| | | | |_) | | 4 | (__| |_| | _ <| |___ 5 \___|\___/|_| \_\_____| 6 7 When Contributing Source Code 8 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. 12 13 1. Learning cURL 14 1.1 Join the Community 15 1.2 License 16 1.3 What To Read 17 18 2. cURL Coding Standards 19 2.1 Naming 20 2.2 Indenting 21 2.3 Commenting 22 2.4 Line Lengths 23 2.5 General Style 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 28 2.10 Document 29 2.11 Test Cases 30 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 38 39============================================================================== 40 411. Learning cURL 42 431.1 Join the Community 44 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. 49 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 52 53 We also hang out on IRC in #curl on irc.freenode.net 54 551.2. License 56 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 59 otherwise. 60 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). 67 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 71 author(s). 72 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! 78 791.3 What To Read 80 81 Source code, the man pages, the INTERNALS document, TODO, KNOWN_BUGS, the 82 most recent CHANGES. Just lurking on the libcurl mailing list is gonna give 83 you a lot of insights on what's going on right now. Asking there is a good 84 idea too. 85 862. cURL Coding Standards 87 882.1 Naming 89 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. 95 96 See the INTERNALS document on how we name non-exported library-global 97 symbols. 98 992.2 Indenting 100 101 Please try using the same indenting levels and bracing method as all the 102 other code already does. It makes the source code a lot easier to follow if 103 all of it is written using the same style. We don't ask you to like it, we 104 just ask you to follow the tradition! ;-) This mainly means: 2-level indents, 105 using spaces only (no tabs) and having the opening brace ({) on the same line 106 as the if() or while(). 107 108 Also note that we use if() and while() with no space before the parenthesis. 109 1102.3 Commenting 111 112 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. 117 1182.4 Line Lengths 119 120 We write source lines shorter than 80 columns. 121 1222.5 General Style 123 124 Keep your functions small. If they're small you avoid a lot of mistakes and 125 you don't accidentally mix up variables etc. 126 1272.6 Non-clobbering All Over 128 129 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. 135 1362.7 Platform Dependent Code 137 138 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. 142 1432.8 Write Separate Patches 144 145 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. 153 1542.9 Patch Against Recent Sources 155 156 Please try to get the latest available sources to make your patches 157 against. It makes the life of the developers so much easier. The very best is 158 if you get the most up-to-date sources from the git repository, but the 159 latest release archive is quite OK as well! 160 1612.10 Document 162 163 Writing docs is dead boring and one of the big problems with many open source 164 projects. Someone's gotta do it. It makes it a lot easier if you submit a 165 small description of your fix or your new features with every contribution so 166 that it can be swiftly added to the package documentation. 167 168 The documentation is always made in man pages (nroff formatted) or plain 169 ASCII files. All HTML files on the web site and in the release archives are 170 generated from the nroff/ASCII versions. 171 1722.11 Test Cases 173 174 Since the introduction of the test suite, we can quickly verify that the main 175 features are working as they're supposed to. To maintain this situation and 176 improve it, all new features and functions that are added need to be tested 177 in the test suite. Every feature that is added should get at least one valid 178 test case that verifies that it works as documented. If every submitter also 179 posts a few test cases, it won't end up as a heavy burden on a single person! 180 1813. Pushing Out Your Changes 182 1833.1 Write Access to git Repository 184 185 If you are a frequent contributor, or have another good reason, you can of 186 course get write access to the git repository and then you'll be able to push 187 your changes straight into the git repo instead of sending changes by mail as 188 patches. Just ask if this is what you'd want. You will be required to have 189 posted a few quality patches first, before you can be granted push access. 190 1913.2 How To Make a Patch with git 192 193 You need to first checkout the repository: 194 195 git clone git://github.com/bagder/curl.git 196 197 You then proceed and edit all the files you like and you commit them to your 198 local repository: 199 200 git commit [file] 201 202 As usual, group your commits so that you commit all changes that at once that 203 constitutes a logical change. See also section "3.5 Write good commit 204 messages". 205 206 Once you have done all your commits and you're happy with what you see, you 207 can make patches out of your changes that are suitable for mailing: 208 209 git format-patch remotes/origin/master 210 211 This creates files in your local directory named NNNN-[name].patch for each 212 commit. 213 214 Now send those patches off to the curl-library list. You can of course opt to 215 do that with the 'git send-email' command. 216 2173.3 How To Make a Patch without git 218 219 Keep a copy of the unmodified curl sources. Make your changes in a separate 220 source tree. When you think you have something that you want to offer the 221 curl community, use GNU diff to generate patches. 222 223 If you have modified a single file, try something like: 224 225 diff -u unmodified-file.c my-changed-one.c > my-fixes.diff 226 227 If you have modified several files, possibly in different directories, you 228 can use diff recursively: 229 230 diff -ur curl-original-dir curl-modified-sources-dir > my-fixes.diff 231 232 The GNU diff and GNU patch tools exist for virtually all platforms, including 233 all kinds of Unixes and Windows: 234 235 For unix-like operating systems: 236 237 http://www.gnu.org/software/patch/patch.html 238 http://www.gnu.org/directory/diffutils.html 239 240 For Windows: 241 242 http://gnuwin32.sourceforge.net/packages/patch.htm 243 http://gnuwin32.sourceforge.net/packages/diffutils.htm 244 2453.4 How to get your changes into the main sources 246 247 Submit your patch to the curl-library mailing list. 248 249 Make the patch against as recent sources as possible. 250 251 Make sure your patch adheres to the source indent and coding style of already 252 existing source code. Failing to do so just adds more work for me. 253 254 Respond to replies on the list about the patch and answer questions and/or 255 fix nits/flaws. This is very important. I will take lack of replies as a sign 256 that you're not very anxious to get your patch accepted and I tend to simply 257 drop such patches from my TODO list. 258 259 If you've followed the above paragraphs and your patch still hasn't been 260 incorporated after some weeks, consider resubmitting it to the list. 261 2623.5 Write good commit messages 263 264 A short guide to how to do fine commit messages in the curl project. 265 266 ---- start ---- 267 [area]: [short line describing the main effect] 268 269 [separate the above single line from the rest with an empty line] 270 271 [full description, no wider than 72 columns that describe as much as 272 possible as to why this change is made, and possibly what things 273 it fixes and everything else that is related] 274 ---- stop ---- 275 276 Don't forget to use commit --author="" if you commit someone else's work, 277 and make sure that you have your own user and email setup correctly in git 278 before you commit 279 2803.6 Please don't send pull requests 281 282 With git (and especially github) it is easy and tempting to send a pull 283 request to one or more people in the curl project to have changes merged this 284 way instead of mailing patches to the curl-library mailing list. 285 286 We don't like that. We want them mailed for these reasons: 287 288 - Peer review. Anyone and everyone on the list can review, comment and 289 improve on the patch. Pull requests limit this ability. 290 291 - Anyone can merge the patch into their own trees for testing and those who 292 have push rights can push it to the main repo. It doesn't have to be anyone 293 the patch author knows beforehand. 294 295 - Commit messages can be tweaked and changed if merged locally instead of 296 using github. Merges directly on github requires the changes to be perfect 297 already, which they seldom are. 298 299 - Merges on github prevents rebases and even enforces --no-ff which is a git 300 style we don't otherwise use in the project 301 302 However: once patches have been reviewed and deemed fine on list they are 303 perfectly OK to be pulled from a published git tree. 304