Read the new developers guide first.
Basic Guidelines and Coding Style
Most of the following should be common sense for anybody who has worked on open source or in a commercial programming envrionment. The following applies mostly to the main development branch i2p.i2p. Guidelines for other branches, plugins, and external apps may be substantially different; check with the appropriate developer for guidance.
Community
- Please don't just "write code". If you can, participate in other development activities, including: development discussions and support on IRC, zzz.i2p, and forum.i2p; testing; bug reporting and responses; documentation; code reviews; etc.
- Active devs should be available periodically on IRC #i2p-dev. Be aware of the current release cycle. Adhere to release milestones such as feature freeze, tag freeze, and the checkin deadline for a release.
Monotone
- Have a basic understanding of distributed source control systems, even if you haven't used monotone before. Ask for help if you need it. Once pushed, checkins are forever, there is no undo. Please be careful. If you have not used monotone before, start with baby steps. Check in some small changes and see how it goes.
- Test your changes before checking them in. If you prefer the checkin-before-test development model, use your own development branch (e.g. i2p.i2p.yourname.test) and propagate back to i2p.i2p once it is working well. Do not break the build. Do not cause regressions. In case you do (it happens), please do not vanish for a long period after you push your change.
- If your change is non-trivial, or you want people to test it and need good test reports to know whether your change was tested or not, add a checkin comment to history.txt and increment the build revision in RouterVersion.java.
- Ensure that you have the latest monotonerc file in _MTN. Do not check in on top of untrusted revisions.
- Ensure that you pull the latest revision before you check in. If you inadvertently diverge, merge and push as soon as possible. Don't routinely make others merge for you. Yes, we know that monotone says you should push and then merge, but in our experience, in-workspace merge works just as well as in-database merge, without creating a merge revision.
- Do not check in major changes into the main i2p.i2p branch late in the release cycle. If a project will take you more than a couple days, create your own branch in monotone and do the development there so you do not block releases.
Coding Style
- Coding style throughout most of the code is 4-spaces for indentation. Do not use tabs. Do not reformat code. If your IDE or editor wants to reformat everything, get control of it. Yes, we know 4 spaces is a pain, but perhaps you can configure your editor appropriately. In some places, the coding style is different. Use common sense. Emulate the style in the file you are modifying.
- New classes and methods require at least brief javadocs. Add @since release-number.
- Classes in core/ (i2p.jar) and portions of i2ptunnel are part of our official API. There are several out-of-tree plugins and other applications that rely on this API. Be careful not to make any changes that break compatibility. Don't add methods to the API unless they are of general utility. Javadocs for API methods should be clear and complete. If you add or change the API, also update the documentation on the website (i2p.www branch).
- Tag strings for translation where appropriate. Don't change existing tagged strings unless really necessary, as it will break existing translations. Do not add or change tagged strings after the "tag freeze" in the release cycle so that translators have a chance to update before the release.
- Use generics and concurrent classes where possible. I2P is a highly multi-threaded application.
- We require Java 6 to build but only Java 5 to run I2P. Do not use Java 6 classes or methods without handling the class not found exceptions and providing alternate Java 5 code. See classes in net.i2p.util for examples.
- Explicitly convert between primitive types and classes; don't rely on autoboxing/unboxing.
Licenses
- Only check in code that you wrote yourself. Before checking in any code or library jars from other sources, justify why it is necessary, verify the license is compatible, and obtain approval from the lead developer.
- For any images checked in from external sources, it is your responsibility to first verify the license is compatible. Include the license and source information in the checkin comment.
Bugs
- Managing Trac tickets is everybody's job, please help. Monitor trac.i2p2.i2p for tickets you have been assigned or can help with. Asssign, categorize, comment on, fix, or close tickets if you can.
- Close a ticket when you think you've fixed it. We don't have a test department to verify and close tickets. If you arent sure you fixed it, close it and add a note saying "I think I fixed it, please test and reopen if it's still broken". Add a comment with the dev build number or revision and set the milestone to the next release.