Contributing to Paper

PaperMC has a very lenient policy towards PRs, but would prefer that you try and adhere to the following guidelines.

Understanding Patches

Patches to Paper are very simple, but center around the directories 'Paper-API' and 'Paper-Server'

Assuming you already have forked the repository:

Pull the latest changes from the main repository
Type ./applyPatches.sh in git bash to apply the changes from upstream
cd into Paper-Server for server changes, and Paper-API for api changes

These directories aren't git repositories in the traditional sense:

Every single commit in Paper-Server/API is a patch.
'origin/master' points to a directory similar to Paper-Server/API but for Paper
Typing git status should show that we are 10 or 11 commits ahead of master, meaning we have 10 or 11 patches that Paper and Spigot don't
- If it says something like 212 commits ahead, 207 commits behind, then type git fetch to update spigot/paper

Adding Patches

Adding patches to Paper is very simple:

Modify Paper-Server and/or Paper-API with the appropriate changes
Type git add . to add your changes
Run git commit with the desired patch message
Run ./rebuildPatches.sh in the main directory to convert your commit into a new patch
PR your patches back to this repository

Your commit will be converted into a patch that you can then PR into Paper

Modifying Patches

Modifying previous patches is a bit more complex:

Make sure git status is correct

If it says something like 212 commits ahead, 207 commits behind, then type git fetch to update spigot

If you have changes you are working on type git stash to store them for later

Later you can type git stash pop to get them back

Type git rebase -i

It should show something like this

Replace pick with edit for the commit/patch you want to modify, and "save" the changes

Only do this for one commit until you get more advanced and understand what git rebase -i does

Make the changes you want to make to the patch
Type git add . to add your changes
Type git commit --amend to commit

MAKE SURE TO ADD --amend or else a new patch will be created
You can also modify the commit message here

Type git rebase --continue to finish rebasing
Type ./rebuildPatches.sh in the main directory

This will modify the appropriate patches based on your commits

PR your modifications to github

PR Policy

We'll accept changes that make sense. You should be able to justify their existence, along with any maintenance costs that come with them. Remember, these changes will affect everyone who runs Paper, not just you and your server. While we will fix minor formatting issues, you should stick to the guide below when making and submitting changes.

Formatting

All modifications to non-Paper files should be marked

Multi line changes start with // Paper start and end with // Paper end
You can put a messages with a change if it isn't obvious, like this: `// Paper start - reason
- Should generally be about the reason the change was made, what it was before, or what the change is
- Multi-line messages should start with // Paper start and use /* Multi line message here */ for the message itself
Single line changes should have // Paper or // Paper - reason
For example:

entity.getWorld().dontbeStupid(); // Paper - was beStupid() which is bad
entity.getFriends().forEach(Entity::explode());
entity.a();
entity.b();
// Paper start - use plugin-set spawn
// entity.getWorld().explode(entity.getWorld().getSpawn());
Location spawnLocation = ((CraftWorld)entity.getWorld()).getSpawnLocation();
entity.getWorld().explode(new BlockPosition(spawnLocation.getX(), spawnLocation.getY(), spawnLocation.getZ()));
// Paper end

We generally follow usual java style, or what is programmed into most IDEs and formatters by default
- This is also known as oracle style
- It is fine to go over 80 lines as long as it doesn't hurt readability
- There are exceptions, especially in Spigot-related files
- When in doubt, use the same style as the surrounding code

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