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Contribute

Opening new issue? Please read ISSUES.md first.

Contributing to Cataclysm: Dark Days Ahead is easy - simply fork the repository here on GitHub, make your changes, and then send us a pull request.

Cataclysm:Dark Days Ahead is released under the Creative Commons Attribution ShareAlike 3.0 license. The code and content of the game is free to use, modify, and redistribute for any purpose whatsoever. See http://creativecommons.org/licenses/by-sa/3.0/ for details. This means any contribution you make to the project will also be covered by the same license, and this license is irrevocable.

Guidelines

There are a couple of guidelines we suggest sticking to:

  • Add this repository as an upstream remote.
  • Keep your master branch clean. This means you can easily pull changes made to this repository into yours.
  • Create a new branch for each new feature or set of related bug fixes.
  • Never merge from your local branches into your master branch. Only update that by pulling from upstream/master.

Code Style

Current policy is to only update code to the standard style when changing a substantial portion of it, but please do this in a separate commit. See doc/CODE_STYLE.txt for details

Translations

The game uses gettext to display translated texts.

This requires two actions:

  • Marking strings that should be translated in the source.
  • Calling translation functions at run time.

The first action allows automatically extracting those strings, which are given to the translator team. They return a file that maps the original string (usually in English) as it appears in the code to the translated string. This is used at run time by the translation functions (the second action).

Note that only extracted strings can get translated. The original string is used to request the translation, in other words: the original string is the identifier used for a specific translation. If the function doesn't know the translation, it returns the original string.

The empty string is always translated into some debug information, not into an empty string. In most situations, the string can be expected to be non-empty, so you can always translate it. If the string could be empty (and it needs to remain empty after the translation), you'll have to check for this and only translate if non-empty.

Error messages (which indicate a bug in the program) and debug messages should not be translated. If they appear, the player is expected to report them exactly as they were printed by the game.

In practice, you should use one of the following three functions in the source code to get a translation.

String literals that are used in any of these functions are automatically extracted. Non-literal strings are translated at run time, but they won't get extracted.

const char *translated = _("text"); // marked for extraction
const char *untranslated = "text"; // same string as the original above.
// This translates because the input string "text" has been marked
// and a translation for it will be available
const char *translated_again = _(untranslated);
untranslated = "other text";
// This does not translate, the string "other text" was never marked for translation
// and the translation system therefor doesn't know how to translate it.
translated_again = _(untranslated);

Strings from the JSON data files are extracted via the "lang/extract_json_strings.py" script. They can be translated at run time using _().

Using _()

For simple C-strings:

const char *translated = _( "original text" );
// also works directly:
add_msg( _( "You drop the %s." ), the_item_name );

Using pgettext()

If the original string is short or its meaning in isolation is ambiguous (e.g. "blue" can be a color or an emotion), one can add a context to the string. The context is provided to the translators, but is not part of the translated string itself. This is done by calling pgettext. This function's first parameter is the context, the second is the string to be translated.

const char *translated = pgettext("The direction: East", "E");

Using ngettext()

Many languages have plural forms. Some have complex rules for how to form these. To translate the plural form correctly, use ngettext. Its first parameter is the untranslated string in singular, the second parameter is the untranslated string in plural form and the third is used to determine the required plural form.

const char *translated = ngettext( "one zombie.", "many zombies", num_zombies );

Some classes (like itype and mtype) provide a wrapper for these functions, named nname.

Doxygen Comments

Extensive documentation of classes and class members will make the code more readable to new contributors. New doxygen comments for existing classes are a welcomed contribution.

Use the following template for commenting classes:

/**
 * Brief description
 *
 * Lengthy description with many words. (optional)
 */
class foo {

Use the following template for commenting functions:

/**
 * Brief description
 *
 * Lengthy description with many words. (optional)
 * @param param1 Description of param1 (optional)
 * @return Description of return (optional)
 */
int foo(int param1);

Use the following template for commenting member variables:

/** Brief description **/
int foo;

Helpful pages: http://www.stack.nl/~dimitri/doxygen/manual/commands.html http://www.stack.nl/~dimitri/doxygen/manual/markdown.html#markdown_std http://www.stack.nl/~dimitri/doxygen/manual/faq.html

Guidelines for adding documentation

  • Doxygen comments should describe behavior towards the outside, not implementation, but since many classes in Cataclysm are intertwined, it's often necessary to describe implementation.
  • Describe things that aren't obvious to newcomers just from the name.
  • Don't describe redundantly: /** Map **/; map* map; is not a helpful comment.
  • When documenting X, describe how X interacts with other components, not just what X itself does.

Building the documentation for viewing it locally

  • Install doxygen
  • doxygen doxygen_doc/doxygen_conf.txt
  • firefox doxygen_doc/html/index.html (replace firefox with your browser of choice)

Example Workflow

Setup your environment

(This only needs to be done once.)

  1. Fork this repository here on GitHub.

  2. Clone your fork locally.

     $ git clone https://github.com/YOUR_USERNAME/Cataclysm-DDA.git
     # Clones your fork of the repository into the current directory in terminal
    
  3. Add this repository as a remote.

     $ cd Cataclysm-DDA
     # Changes the active directory in the prompt to the newly cloned "Cataclysm-DDA" directory
     $ git remote add -f upstream https://github.com/CleverRaven/Cataclysm-DDA.git
     # Assigns the original repository to a remote called "upstream"
    

Update your master branch

  1. Make sure you have your master branch checked out.

     $ git checkout master
    
  2. Pull the changes from the upstream/master branch.

     $ git pull --ff-only upstream master
     # gets changes from "master" branch on the "upstream" remote
    

Make your changes

  1. Update your master branch, if you haven't already.

  2. For each new feature or bug fix, create a new branch.

     $ git branch new_feature
     # Creates a new branch called "new_feature"
     $ git checkout new_feature
     # Makes "new_feature" the active branch
    
  3. Once you've committed some changes locally, you need to push them to your fork here on GitHub.

     $ git push origin new_feature
     # origin was automatically set to point to your fork when you cloned it
    
  4. Once you're finished working on your branch, and have committed and pushed all your changes, submit a pull request from your new_feature branch to this repository's master branch.

  • Note: any new commits to the new_feature branch on GitHub will automatically be included in the pull request, so make sure to only commit related changes to the same branch.

Pull Request Notes

  • Mark pull requests that are still being worked on by adding [WIP] before the title
    • When a pull request is ready to be reviewed remove the [WIP]
  • Mark pull requests that need commenting/testing by others with [CR] before the title
    • [WIP] has higher precedence than [CR]. Feel free to remove [CR] when you feel you got enough information
  • If the pull request fixes a issue listed on github, include "fixes #???" into the text, where ??? is the number of the issue. This automatically closes the issue when the PR is pulled in, and allows mergers to work slightly faster. For further details see issue #2419.

Advanced Techniques

These guidelines aren't essential, but they can make keeping things in order much easier.

Using remote tracking branches

Remote tracking branches allow you to easily stay in touch with this repository's master branch, as they automatically know which remote branch to get changes from.

$ git branch -vv
* master      xxxx [origin/master] ....
  new_feature xxxx ....

Here you can see we have two branches; master which is tracking origin/master, and new_feature which isn't tracking any branch. In practice, what this means is that git won't know where to get changes from.

$ git checkout new_feature
Switched to branch 'new_feature'
$ git pull
There is no tracking information for the current branch.
Please specify which branch you want to merge with.

In order to easily pull changes from upstream/master into the new_feature branch, we can tell git which branch it should track. (You can even do this for your local master branch.)

$ git branch -u upstream/master new_feature
Branch new_feature set up to track remote branch master from upstream.
$ git pull
Updating xxxx..xxxx
....

You can also set the tracking information at the same time as creating the branch.

$ git branch new_feature_2 --track upstream/master
Branch new_feature_2 set up to track remote branch master from upstream.
  • Note: Although this makes it easier to pull from upstream/master, it doesn't change anything with regards to pushing. git push fails because you don't have permission to push to upstream/master.

     $ git push
     error: The requested URL returned error: 403 while accessing https://github.com/CleverRaven/Cataclysm-DDA.git
     fatal: HTTP request failed
     $ git push origin
     ....
     To https://github.com/YOUR_USERNAME/Cataclysm-DDA.git
     xxxx..xxxx  new_feature -> new_feature
    

PR Tags

If you file a PR but you're still working on it, please add a [WIP] before the title text. This will tell the reviewers that you still intend to add more to the PR and we don't need to review it yet. When it's ready to be reviewed by a merger just edit the title text to remove the [WIP].

If you are also looking for suggestions then mark it with [CR] - "comments requested". You can use both [WIP] and [CR] to indicated that you need opinion/code review/suggestions to continue working (e.g. "[WIP] [CR] Super awesome big feature"). Feel free to remove [CR] when you feel you got enough information to proceed.

This can help speed up our review process by allowing us to only review the things that are ready for it, and will prevent anything that isn't completely ready from being merged in.

One more thing: when marking your PR as closing, fixing, or resolving issues, please include "XXXX #???" somewhere in the description, where XXX is on this list: close closes closed fix fixes fixed resolve resolves resolved The "???" is the issue number. This automatically closes the issue when the PR is pulled in, and allows merges to work slightly faster. To close multiple issues format it as "XXXX #???, XXXX#???".

In-game testing, test environment and the debug menu

Whether you are implementing a new feature or whether you are fixing a bug, it is always a good practice to test your changes in-game. It can be a hard task to create the exact conditions by playing a normal game to be able to test your changes, which is why there is a debug menu. There is no default key to bring up the menu so you will need to assign one first.

Bring up the keybindings menu (press Escape then 1), scroll down almost to the bottom and press + to add a new key binding. Press the letter that corresponds to the Debug menu item, then press the key you want to use to bring up the debug menu. To test your changes, create a new world with a new character. Once you are in that world, press the key you just assigned for the debug menu and you should see something like this:

┌────────────────────────────────────────────┐
│ Debug Functions - Using these is CHEATING! │
├────────────────────────────────────────────┤
│ 1 Wish for an item                         │
│ 2 Teleport - Short Range                   │
│ 3 Teleport - Long Range                    │
│ 4 Reveal map                               │
│ 5 Spawn NPC                                │
│ 6 Spawn Monster                            │
│ 7 Check game state...                      │
│ 8 Kill NPCs                                │
│ 9 Mutate                                   │
│ 0 Spawn a vehicle                          │
│ a Change all skills                        │
│ b Learn all melee styles                   │
│ c Unlock all recipes                       │
│ d Edit player/NPC                          │
│ e Spawn Artifact                           │
│ f Spawn Clairvoyance Artifact              │
│ g Map editor                               │
│ h Change weather                           │
│ i Remove all monsters                      │
│ j Display hordes                           │
│ k Test Item Group                          │
│ l Damage Self                              │
│ m Show Sound Clustering                    │
│ n Lua Command                              │
│ o Display weather                          │
│ p Change time                              │
│ q Set automove route                       │
│ r Show mutation category levels            │
│ s Cancel                                   │
└────────────────────────────────────────────┘

With these commands, you should be able to recreate the proper conditions to test your changes. You can find some more information about the debug menu on the official wiki.

Frequently Asked Questions

####Why does git pull --ff-only result in an error?

If git pull --ff-only shows an error, it means that you've committed directly to your local master branch. To fix this, we create a new branch with these commits, find the point at which we diverged from upstream/master, and then reset master to that point.

$ git pull --ff-only upstream master
From https://github.com/CleverRaven/Cataclysm-DDA
 * branch            master     -> FETCH_HEAD
fatal: Not possible to fast-forward, aborting.
$ git branch new_branch master          # mark the current commit with a tmp branch
$ git merge-base master upstream/master
cc31d0... # the last commit before we committed directly to master
$ git reset --hard cc31d0....
HEAD is now at cc31d0... ...

Now that master has been cleaned up, we can easily pull from upstream/master, and then continue working on new_branch.

$ git pull --ff-only upstream master
# gets changes from the "upstream" remote for the matching branch, in this case "master"
$ git checkout new_branch