IntelliJ-IdeaVim/CONTRIBUTING.md

IdeaVim is an open source project created by 60+ contributors. Would you like to make it even better? That’s wonderful!

This page is created to help you start contributing. And who knows, maybe in a few days this project will be brighter than ever!

Before you begin

• The project is written in Kotlin and Java. Choose whichever language you feel more comfortable with, or maybe one that you’d like to get to know better (why not start learning Kotlin right now?).

• If you come across some IntelliJ Platform code, these links may prove helpful:

  • IntelliJ architectural overview
  • IntelliJ plugin development resources

• Having any difficulties? Join the brand new for IdeaVim developers and contributors!

OK, ready to do some coding?

Yes, I'm ready for some coding

• Fork the repository and clone it to the local machine.
• Open the project with IntelliJ IDEA.

Yoo hoo! You’re all set to begin contributing. We've prepared some useful configurations for you:

And here are useful gradle commands:

• ./gradlew runIde — start the dev version of IntelliJ IDEA with IdeaVim installed.
• ./gradlew test — run tests.
• ./gradlew buildPlugin — build the plugin. The result will be located in build/distributions. This file can be installed by using Settings | Plugin | >Gear Icon< | Install Plugin from Disk.... You can stay with your personal build for a few days or send it to a friend for testing.

Warmup

• Pick a few relatively simple tasks that are tagged with #patch_welcome in the issue tracker.
• Read the javadoc for the @VimBehaviorDiffers annotation in the source code and fix the corresponding functionality.
• Implement one of the requested #vim plugins.

🔸 Selected an issue to work on? Leave a comment in a YouTrack ticket or create a draft PR to indicate that you've started working on it so that you might get additional guidance and feedback from the maintainers.

Where to start in the codebase

If you are looking for:

• Vim commands (w, <C-O>, p, etc.):

  • Any particular command: package-info.java.
  • How commands are executed in common: EditorActionHandlerBase.
  • Key mapping: KeyHandler.handleKey().

• Ex commands (:set, :s, :nohlsearch):

  • Any particular ex command: package com.maddyhome.idea.vim.ex.handler.
  • Ex command executor: CommandHandler.

• Extensions:

  • Extensions handler: VimExtensionHandler.
  • Available extensions: package com/maddyhome/idea/vim/extension.

• Common features:

  • State machine. How every particular keystroke is parsed in IdeaVim: KeyHandler.handleKey().
  • Options (incsearch, iskeyword, relativenumber): OptionsManager.
  • Plugin startup: PluginStartup.
  • Notifications: NotificationService.
  • Status bar icon: StatusBar.kt.
  • On/off switch: VimPlugin.setEnabled().

Testing

Here are some guides for testing:

1. Read the javadoc for the @VimBehaviorDiffers annotation in the source code.

2. Please avoid senseless text like "dhjkwaldjwa", "asdasdasd", "123 123 123 123", etc. Try to choose an example text that is easy to read and understand what is wrong if the test fails. For example, take a few lines from your favorite poem, or use Vladimir Nabokov’s “A Discovery" if you don't have one.

3. Don't forget to test your functionality with line start, line end, file start, file end, empty line, multiple carets, dollar motion, etc.

Neovim

IdeaVim has an experimental integration with neovim in tests. Tests that are performed with doTest also executed in neovim instance, and the state of IdeaVim is asserted to be the same as the state of neovim.

• Only tests that use doTest are checked with neovim.
• Tests with @VimBehaviorDiffers or @TestWithoutNeovim annotations don't use neovim.

Property-based tests

Property-based tests are located under propertybased package. These tests a flaky by nature although in most cases they are stable. If the test fails on your TeamCity run, try to check the test output and understand if the fail is caused by your changes. If it's not, just ignore the test.

A common direction

We’re trying to make IdeaVim close to the original Vim both in terms of functionality and architecture.

• Vim motions can be either inclusive, exclusive, or linewise. In IdeaVim, you can use MotionType for that.
• Have you read the interesting things about IdeaVim? Do you remember how dd, yy, and other similar commands work? DuplicableOperatorAction will help you with that. And we also translate it to d_ and y_: KeyHandler.mapOpCommand().
• All IdeaVim extensions use the same command names as the originals (e.g. <Plug>(CommentMotion), <Plug>ReplaceWithRegisterLine), so you can reuse your .vimrc settings. We also support proper command mappings (functions are mapped to <Plug>...), the operator function (OperatorFunction), and so on.
• Magic is supported as well. See Magic.

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I read the whole page but something is still unclear.

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I’ve found a bug in this documentation.

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The lack of documentation or a javadoc/ktdoc makes it difficult to start contributing.

This is just terrible. You know what to do.

Resources:

• Continuous integration builds
• Bug tracker
• Chat on gitter
• Unofficial discord server
• Plugin homepage
• Changelog
• Contributors listing