Contributing to CTK

The present document aims at describing how a developer should contribute to CTK.

• The source code of CTK is currently hosted on Github. See http://github.com/commontk/CTK

• It's also assumed the developer is familiar with git [1]. There are countless amount of resources available online. A good start point could the list presented on CMake/git page.

• We use a topic-based workflow as documented here and thus define integration branche(s):
  • master Development; starting point for new features (default)

Prerequisites

• Create an account on github.com
• Fork http://github.com/commontk/CTK
• Introduce yourself

$ git config --global user.name "Your Name"
$ git config --global user.email "you@yourdomain.com"

• Use correct line endings (more info)

[On Linux] $ git config --global core.autocrlf input
[On Windows] $ git config --global core.autocrlf true

Checkout your fork

cd MyProject
git clone git@github.com:<MYACCOUNT>/CTK.git
cd CTK
git remote add origin git@github.com:<MYACCOUNT>/CTK.git
git remote add upstream git@github.com:commontk/CTK.git

Publishing your branch

• Having your own fork CTK allows you to backup and publish your work avoiding the urge to merge [2]

git checkout -b YYY-new-feature
hack, hack, hack, add, commit
git push origin topic1:refs/heads/YYY-new-feature

• Note that YYY reference an issue entered in the tracker.

• As a shortcut, you could also enter the following. Some useful script are also available here:

git config branch.topic1.remote origin
git config branch.topic1.merge refs/heads/YYY-new-feature

• Then, from the topic branch YYY-new-feature, you could just enter the following to backup/publish your work:

git push

• From there, you have two options:
  • Send an email on the developer list referencing your topic
  • Submit a pull request [3]

• To delete a branch from your fork:

git push origin :YYY-new-feature

Checkout a branch from a different fork

• You may want to collaborate with an other developer and work conjointly on a feature.
• Let's say, jcfr published the branch awesome_feature on his fork. You should do the following to check out his branch:

git remote add jcfr git://github.com/jcfr/CTK.git
git fetch jcfr
git checkout -b awesome_feature refs/remotes/jcfr/awesome_feature

or

git checkout -b awesome_feature jcfr/awesome_feature

• You should now have a local branch named awesome_feature. You can now add, commit and publish your work.

Sync your topic branch

• If a collaborator previously checked out your published branch, committed some changes, then published a revised branch on his github fork, you may want to grab its changes.
• Different ways:

1) If you didn't work on your branch, you could do the following:

git fetch jcfr
git checkout my_topic
git merge jcfr/my_topic

2) If you worked on your branch while your collaborator was working, you may want to select only the commit your collaborator pushed on his fork:

git fetch jcfr
git checkout my_topic
git cherry-pick <sha1>   # sha1 identifying a specific commit

Integrate your new feature

After it has been validated and tested, your changes could be integrated to master following two approaches:

• Direct integration

git fetch upstream                             # Retrieve change from upstream repository
git checkout master                            # Checkout your local "master" branch
git reset --hard upstream/master               # Make sure your local branch is up-to-date.
git merge new_feature --log --no-ff            # Merge locally to "master" - Your changes are now integrated
git push upstream                              # Publish your change on the official repository
git push origin                                # Publish your change on your fork

• Pull request integration

Git Commit Style

• Write very descriptive and concise first line summary of your commit
  • try to stick to 50 characters max (no more than 65)
  • do not use 'COMP' 'ENH' etc. (these cut into your 50 characters)
  • summary should be a complete English sentence starting with a capital letter (terminating period is optional). Ideally the sentence should be using present tense ("Add" vs "Added", "Fix" vs "Made fixes"...)
• Include a blank line after the summary and then a more detailed multi-line description (72 character max line length)
• In the body of the commit message, include #123 where 123 is the issue number. If a final commit fixes the issue, include "Fixes #123" or "Closes #123" in the commit message.
• Use git merge --log --no-ff <topicname> (this keeps the logs messages of the merged branch)

CTK Coding Style

The overall policy is to follow the coding conventions of the parent classes unless there is an accepted CTK exception to improve consistency or usability (to account for inconsistency in the parent class system).

• If you are writing a widget that inherits from QObject, all your code should follow Qt coding conventions.
  • Use the Private Implementation approach ("PIMPL") except make the member variables of your private class begin with a capital letter. This means that when you create a widget using the QtDesigner, you must rename the widget to a local name that begins with a capital letter (since this will be an instance variable in your private implementation).

• Use virtual keyword also in derived class. Doing so improve readability of the code.

• Use const reference if it applies. For example:

 void setName(const QString& newName); // better
 void setName(QString newName); // poor

• Use comment line separator. For example:

...

//----------------------------------------------------------------------------
void Foo::setName(const QString& newName)
{
  Q_D(Foo);
  d->Name = newName;
}

//----------------------------------------------------------------------------
QString Foo::name() const
{
  Q_D(const Foo);
  return d->Name;
}
...

• The following statements for, while, switch, if, else, try, catch should, most of time, be multi-line. The brackets should also be indented with 2 spaces. For example:

//----------------------------------------------------------------------------
bool Foo::doSomething(int count)
{
  // Better
  for(int i=1; i < count; ++i)
    {
    if (i == 100)
      {
      qDebug() << "i = 100";
      break;
      }
    }

  // Poor
  for(int i=1; i < count; ++i)
    if (i == 100) { qDebug() << "i = 100"; break; }
}

• Within CMakeLists.txt files, source/header file names should be sorted alphabetically. It also applies with inclusion order in header/implementation files
• Prefer to use normalised signal/slot signatures

FAQ

• What the meaning of fatal: The current branch master is not tracking anything. ?