qTox/CONTRIBUTING.md

Note that you don't need to know all of the CONTRIBUTING.md – it is there to help you with things as you go, and make things easier, not harder.

Skim through it, and when you will be doing something that relevant section will apply to, just go back to it and read in more detail about what is the best course of action. You don't even need to memorize the section – after all, it still will be there next time you might need it. :-)

Filing an issue

Must read

• If you aren't sure, you can ask on the IRC channel or read our wiki first.
• Do a quick search. Others might have already reported the issue.
• Write in English!
• Provide version information (you can find version numbers in menu Settings → About):

OS: 
qTox version: 
Commit hash: 
toxcore: 
Qt: 

• Provide steps to reproduce the problem, it will be easier to pinpoint the fault.
• Screenshots! A screenshot is worth a thousand words. Just upload it. (How?)

Good to know

• Patience. The dev team is small and resource limited. Devs have to find time, analyze the problem and fix the issue, it all takes time. 🕒
• If you can code, why not become a contributor by fixing the issue and opening a pull request? 😉
• Harsh words or threats won't help your situation. What's worse, your complaint will (very likely) be ignored. 😨

How to start contributing

Before you start…

Before you start contributing, first decide for a specific topic you want to work on. Pull requests, which are spanning multiple topics (e.g. "general qTox code cleanup") or introduce fundamental architectural changes are rare and require additional attention and maintenance. Please also read the following simple rules we need to keep qTox a "smooth experience" for everybody involved.

Must read:

• Use commit message format.
• Read our coding guidelines.
• Keep the title short and provide a clear description about what your pull request does.
• Provide screenshots for UI related changes.
• Keep your git commit history clean and precise by continuously rebasing/amending your PR. Commits like xxx fixup are not needed and rejected during review.
• Commit message should state not only what has been changed, but also why a change is needed.
• If your commit fixes a reported issue (for example #4134), add the following message to the commit Fixes #4134.. Here is an example.

Pull request

PR = Pull request

Ideally for simple PRs (most of them):

• One topic per PR
• One commit per PR
• If you have several commits on different topics, close the PR and create one PR per topic
• If you still have several commits, squash them into only one commit
• Amend commit after making changes (git commit --amend path/to/file)
• Rebase your PR branch on top of upstream master before submitting the PR

For complex PRs (big refactoring, etc):

• Squash only the commits with uninteresting changes like typos, docs improvements, etc… and keep the important and isolated steps in different commits.

It's important to keep amount of changes in the PR small, since smaller PRs are easier to review and merging them is quicker. PR diff shouldn't exceed 300 changed lines, unless it has to.

How to open a pull request

1. Fork the qTox repository on Github to your existing account.
2. Open a Terminal and do the following steps:

# Go to a directory of your choice, where the qTox directory will be created:
cd /to/the/directory

# Clone the forked repo:
git clone git@github.com:<YOUR_USER>/qTox.git

# Add the "upstream" remote to be able to fetch from the qTox upstream repository:
git remote add upstream https://github.com/qTox/qTox.git

# Point the local "master" branch to the "upstream" repository
git branch master --set-upstream-to=upstream/master

You're now all set to create your first pull request! Hooray! :)

Still in Terminal, do the following steps to actually create the pull request:

# Fetch from the "upstream" repository:
git fetch upstream master:master

# Checkout a local branch on up-to-date "master" and give it a sane name, e.g.:
git checkout -b feat/brandnew-feature master

Now do your changes and commit them by your heart's desire. When you think you're ready to push for the first time, do the following:

# Push to the new upstream branch and link it for synchronization
git push -u origin feat/brandnew-feature

# From now on, you can simply…
git push
# ...to your brand new pull request.

That's it! Happy contributing!

How to deal with large amounts of merge conflicts

Usually you want to avoid conflicts and they should be rare. If conflicts appear anyway, they are usually easy enough to solve quickly and safely. However, if you find yourself in a situation with large amounts of merge conflicts, this is an indication that you're doing something wrong and you should change your strategy. Still… you probably don't want to throw away and lose all your valuable work. So don't worry, there's a way to get out of that mess. The basic idea is to divide the conflicts into smaller – easier to solve – chunks and probably several (topic) branches. Here's a little "Rule of Thumb" list to get out of it:

1. Split your commit history into topic related chunks (by rebasing/cherry-picking "good" commits).
2. Split "API" and "UI" (widget related) changes into separate commits.
3. Probably split PR into several smaller ones.

In addition it helps to regularly keep rebasing on the upstream repository's recent master branch. If you don't have the upstream remote in your repo, add it as described in How to open a pull request.

# If not on PR branch, check it out:
git checkout my/pr-branch

# Now fetch master ALWAYS from upstream repo
git fetch upstream master:master

# Last, rebase PR branch onto master…
git rebase -i master

# …and, if everything's clear, force push to YOUR repo (your "origin" Git remote)
git push -f

Good to know

• Search the pull request history! Others might have already implemented your idea and it could be waiting to be merged (or have been rejected already). Save your precious time by doing a search first.
• When resolving merge conflicts, do git rebase <target_branch_name>, don't do git pull. Then you can start fixing the conflicts. Here is a good explanation.

Git Commit Guidelines

We have very precise rules over how our git commit messages can be formatted. This leads to more readable messages that are easy to follow when looking through the project history. But also, we use the git commit messages to generate the qTox change log using clog-cli.

Commit Message Format

Each commit message consists of a header and a body. The header has a special format that includes a type, a scope and a subject:

<type>(<scope>): <subject>
<BLANK LINE>
<body>

The header is mandatory and the body is optional. The scope of the header is also optional.

Header

The header must be a short (72 characters or less) summary of the changes made.

Type

Must be one of the following:

• feat: A new feature
• fix: A bug fix
• docs: Documentation only changes
• style: Changes that do not affect the meaning of the code (white-space, formatting, etc), but change the style to a more appropriate one
• refactor: A code change that only improves code readability and reduces complexity, without changing any functionality
• perf: A code change that improves performance
• revert: Reverts a previous commit
• test: Adding missing tests
• chore: Changes to the build process or auxiliary tools and libraries such as documentation generation

Revert

If the commit reverts a previous commit, it should begin with revert: , followed by the header of the reverted commit. In the body it should say: Revert commit <hash>., where the hash is the SHA of the commit being reverted.

Scope

The scope could be anything specifying place of the commit change. Note that "place" doesn't necessarily mean location in source code.

For example:

• audio – change affects audio
• video – change affects video
• settings – change affects qTox settings
• chatform
• tray – change affects tray icon
• l10n – translation update
• i18n – something has been made translatable
• build – change affects build system / scripts, e.g. qtox.pro, simple_make.sh, etc.
• travis – change affects Travis CI
• CONTRIBUTING – change to the contributing guidelines

Since people were abusing length of the scope, it's limited to 12 characters. If you're running into the limit, you're doing it wrong.

Subject

The subject contains succinct description of the change:

• use the imperative, present tense: "change" not "changed" nor "changes"
• don't capitalize first letter
• no dot (.) at the end

A properly formed git commit subject line should always be able to complete the following sentence:

If applied, this commit will your subject line here

Body

Wrap the body at 72 characters whenever possible (for example, don't modify long links to follow this rule). Just as in the subject, use the imperative, present tense: "change" not "changed" nor "changes". The body should include the motivation for the change and contrast this with previous behavior.

The body contains (in order of appearance):

• A detailed description of the committed changes.
• References to GitHub issues that the commit closes (e.g., Closes #000 or Fixes #000).
• Any breaking changes.

Include every section of the body that is relevant for your commit.

Breaking changes should start with the phrase BREAKING CHANGE: with a space or two newlines. The rest of the commit message is then used for this.

Reviews

Currently reviewable.io is being used to review changes that land in qTox.

How to review:

1. Click on the Reviewable button in pull request.
2. Once Reviewable opens, comment on the lines that need changes.
3. Mark as reviewed only those files that don't require any changes – this makes it easier to see which files need to be changed & reviewed again once change is made.
4. If pull request is good to be merged, press LGTM button in Reviewable.
5. Once you're done with evaluating PR, press Publish to make comments visible on GitHub.

When responding to review:

1. Click on the Reviewable button in pull request.
2. Once you push changes to the pull request, make drafts of responses to the change requests.
   • if you're just informing that you've made a requested change, use Reviewable's provided Done button.
   • if you want discuss the change, write a response draft.
3. When discussion points are addressed, press Publish button to make response visible on GitHub.

Note:

• when no one is assigned to the PR, anyone can review it
• when there are assigned people, only they can mark review as passed

Testing PRs

The easiest way is to use test-pr.sh script to get PR merged on top of current master. E.g. to get pull request #1234:

./test-pr.sh 1234

That should create branches named 1234 and test1234. test1234 is what you would want to test. If script fails to merge branch because of conflicts, fret not, it doesn't need testing until PR author fixes merge conflicts. You might want to leave a comment on the PR saying that it needs a rebase 😄

As for testing itself, there's a nice entry on the wiki: https://github.com/qTox/qTox/wiki/Testing

Git config

Not a requirement, just a friendly tip. 😉

It's nice when commits are being GPG-signed. Github has a few articles about configuring & signing.

https://help.github.com/articles/signing-commits-using-gpg/

And tl;dr version:

gpg --gen-key
gpg --send-keys <your generated key ID>
git config --global commit.gpgsign true

Coding Guidelines

Use C++11.

Includes

On the project level, include files starting with the root directory of the repository, e.g. src/core/core.h from src/widget/widget.cpp:

#include "src/core/core.h"

Do not use <> tags to include files on the project level, e.g. src/core/core.h from src/widget/widget.cpp:

#include <core.h>    // WRONG

If including files from the operating system, external libraries, frameworks or Qt classes use <> tags, e.g. cstdio and QString from src/main.cpp:

#include <cstdio>
#include <QString>

Coding style

function()
{
    1st_line;
    2nd_line;
}

// if / while / for / switch
// always use curly brackets
if () // ← note the space between `if` and parenthesis
{
    1_line_curly;
}
else if ()
{
    just_one_line;
}
else
{
    each_condition_in_curly;
}

QObject* asterisksGoWithTheType;
uint8_t* array = new uint8_t[count];

// camelCase for variables, CamelCase for classes
QObject notToMentionThatWeUseCamelCase;

Dynamic casts / RTTI

qTox is compiled without support for RTTI, as such PRs making use of dynamic_cast() will fail to compile and may be rejected on this basis. For manipulating Qt-based objects, use qobject_cast() instead.

Compiling qTox without RTTI support gives up to 5-6% size reductions on compiled binary files. The usage of dynamic_cast() can also be completely mitigated when dealing with Qt objects through use of qobject_cast() which behaves very much like C++'s dynamic_cast() but without the RTTI overhead.

Enforced with -fno-rtti.

Documentation

If you added a new function, also add a doxygen comment before the implementation. If you changed an old function, make sure the doxygen comment is still correct. If it doesn't exist add it.

Don't put docs in .h files, if there is a corresponding .cpp file.

Documentation style

/*...license info...*/
#include "blabla.h"

/**
 * @brief I can be briefly described as well!
 *
 * And here goes my longer descrption!
 *
 * @param x Description for the first parameter
 * @param y Description for the second paramater
 * @return An amazing result
 */
static int example(int x, int y)
{
    // Function implementation...
}

/**
 * @class OurClass
 * @brief Exists for some reason...!?
 * 
 * Longer description
 */

/**
 * @enum OurClass::OurEnum
 * @brief The brief description line.
 * 
 * @var EnumValue1
 * means something
 * 
 * @var EnumValue2
 * means something else
 * 
 * Optional long description
 */

/**
 * @fn OurClass::somethingHappened(const QString &happened)
 * @param[in] happened    tells what has happened...
 * @brief This signal is emitted when something has happened in the class.
 * 
 * Here's an optional longer description of what the signal additionally does.
 */

No translatable HTML tags

Do not put HTML in UI files, or inside tr(). Instead, you can put put it in C++ code in the following way, to make only user-facing text translatable:

someWidget->setTooltip(
    QStringLiteral("<html><!-- some HTML text -->") + tr("Translatable text…") +
    QStringLiteral("</html>");

Limitations

Filesystem

Windows' unbeaten beauty and clarity:

https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247%28v=vs.85%29.aspx

Symbols that should be forbidden for filenames under Windows:

< > : " / \ | ? *