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 curl-library mailing list is gonna 83 give you a lot of insights on what's going on right now. Asking there is a 84 good 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 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() 106 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. 153 154 Also, separate patches enable bisecting much better when we track problems in 155 the future. 156 1572.9 Patch Against Recent Sources 158 159 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! 163 1642.10 Document 165 166 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. 170 171 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. 174 1752.11 Test Cases 176 177 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! 183 184 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. 187 1883. Pushing Out Your Changes 189 1903.1 Write Access to git Repository 191 192 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. 197 1983.2 How To Make a Patch with git 199 200 You need to first checkout the repository: 201 202 git clone git://github.com/bagder/curl.git 203 204 You then proceed and edit all the files you like and you commit them to your 205 local repository: 206 207 git commit [file] 208 209 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 211 messages". 212 213 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: 215 216 git format-patch remotes/origin/master 217 218 This creates files in your local directory named NNNN-[name].patch for each 219 commit. 220 221 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. 223 2243.3 How To Make a Patch without git 225 226 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. 229 230 If you have modified a single file, try something like: 231 232 diff -u unmodified-file.c my-changed-one.c > my-fixes.diff 233 234 If you have modified several files, possibly in different directories, you 235 can use diff recursively: 236 237 diff -ur curl-original-dir curl-modified-sources-dir > my-fixes.diff 238 239 The GNU diff and GNU patch tools exist for virtually all platforms, including 240 all kinds of Unixes and Windows: 241 242 For unix-like operating systems: 243 244 http://www.gnu.org/software/patch/patch.html 245 http://www.gnu.org/directory/diffutils.html 246 247 For Windows: 248 249 http://gnuwin32.sourceforge.net/packages/patch.htm 250 http://gnuwin32.sourceforge.net/packages/diffutils.htm 251 2523.4 How to get your changes into the main sources 253 254 Submit your patch to the curl-library mailing list. 255 256 Make the patch against as recent sources as possible. 257 258 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. 260 261 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. 265 266 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. 268 2693.5 Write good commit messages 270 271 A short guide to how to do fine commit messages in the curl project. 272 273 ---- start ---- 274 [area]: [short line describing the main effect] 275 276 [separate the above single line from the rest with an empty line] 277 278 [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] 281 ---- stop ---- 282 283 Don't forget to use commit --author="" if you commit someone else's work, 284 and make sure that you have your own user and email setup correctly in git 285 before you commit 286 2873.6 Please don't send pull requests 288 289 With git (and especially github) it is easy and tempting to send a pull 290 request to one or more people in the curl project to have changes merged this 291 way instead of mailing patches to the curl-library mailing list. 292 293 We don't like that. We want them mailed for these reasons: 294 295 - Peer review. Anyone and everyone on the list can review, comment and 296 improve on the patch. Pull requests limit this ability. 297 298 - Anyone can merge the patch into their own trees for testing and those who 299 have push rights can push it to the main repo. It doesn't have to be anyone 300 the patch author knows beforehand. 301 302 - Commit messages can be tweaked and changed if merged locally instead of 303 using github. Merges directly on github requires the changes to be perfect 304 already, which they seldom are. 305 306 - Merges on github prevents rebases and even enforces --no-ff which is a git 307 style we don't otherwise use in the project 308 309 However: once patches have been reviewed and deemed fine on list they are 310 perfectly OK to be pulled from a published git tree. 311