Difference between revisions of "Development/Tutorials/Git/Feature Development Workflow"
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Revision as of 07:12, 19 May 2011
These tutorials are aimed to get people started with KDE's policy for merging and integrating changes into the repositories.
Such policies vary depending on the developer's role inside the project. Please follow the tutorial which best suits your role and profile
- Casual Developer - follow this tutorial if you simply wish to contribute features or fixes OR you are a developer without specific knowledge of git. Difficulty level: easy
- Core Developer with git knowledge - follow this tutorial if you are a developer which contributes frequently AND you have a more-than-average knowledge of git. Difficulty level: manageable
- Repository Maintainer - follow this tutorial if you are a repository maintainer or if you want to apply for becoming one. Difficulty level: relevant
Also, for your knowledge, you should check out these specific articles:
- Which repository should I use?
- Rationale and explanation of workflow
- Rebase vs. merging: why and how
- The staging phase explained
- Merge strategies to and from integration
- Branches and commit policies
Some KDE Components have adopted an integration-staging-origin policy for pushing features into KDE's repositories. This document is designed to get developers started with this workflow and understand the steps involved.
Repositories and projects complying with this policy
The following repositories/projects follow these guidelines. Any project not mentioned here is unaffected by what described
- kdelibs (plasma only)
The requirements of the KDE community that this workflow aims to meet include:
- master being in a continuously stable state
- the ability to do integration in a branch other than master
- ease of bug fixing, particularly making applying the same fix to stable and integration branches clear and simple
- no interruption to feature development, even during freezes in preparation of Software Compilation releases
- a single workflow applied across all participants in the Software Compilation and, hopefully, even wider across projects hosted in KDE's git installation to keep the barrier to participation low
This approach is meant to implement proper quality evaluation into the main repositories, still allowing developers to work on anything they want, and providing a sane merging strategy which does not require any specific knowledge from the developer's side.
This is achieved by using two separate repositories. One is origin, the official project repository, where just maintainers are allowed to push, apart from special cases. The other is integration, where work in progress happens, and everyone can create branches and work on that.
There are two separate figures: developers and maintainers. Developers are people who want to work on features on a specific repositories, maintainers are the gatekeepers for those repositories. Please note the purpose of the maintainer is purely organizational: no special power over technical decision is given to maintainers.
A developer would provide his code into a remote branch in integration: as soon as this code is ready and reviewed, the maintainer would take care of merging into integration/master first, prepare for staging in integration/staging, and finally merge into master when needed.
Setting up the development environment
In the following tutorial, we'll refer to kdelibs as the main target, but this applies to any other repository using this policy.
Cloning the repository and adding integration
To clone the repository, issue
git clone kde:kdelibs
This will create a kdelibs directory containing the whole repository. You now need to add a separate remote for handling integration. A remote is a repository URL, and your local clone can contain multiple repositories to track different branches. To add kdelibs' integration repository, issue inside kdelibs' clone:
git remote add integration kde:clones/kdelibs/dafre/kdelibs-integration
Now, fetch from integration to retrieve the changes:
git fetch integration
You now need to get your branches set up, in particular integration/master. In this example, we are creating a new branch named integration-master which would serve for this purpose in particular:
git checkout -b integration-master integration/master
This command creates a local branch set to track a remote one. This branch should be the branch you'll be basing your work upon: origin/master is not meant for development!
Using integration vs. using your own clone
It is strongly advised to push your work to integration, but under some circumstances (your work is extremely big in size, you do not have a KDE Development account, etc.), it is allowed to push your branches to a separate personal clone. All work should end up into integration for being reviewed anyway.
Developing a new feature
We'll now walk through the process needed to develop a new feature. We'll suppose you want to add a button which says "hello" to a specific part of code.
Creating a new branch
First thing to do is creating a new branch on which to base your work on. This branch must be based upon integration/master. To make sure this happens, start by issuing
git checkout integration-master
Now create your branch. Give it a self-explainatory name: try to keep branches as atomic as possible, and possibly split big changes throughout multiple branches divided as per topic. In our case, we want to name our branch add-hello-button. To do that, we do:
git checkout -b add-hello-button
That will create our personal branch which is going to contain our work. Push your branch to integration by issuing
git push integration add-hello-button
Getting the branch reviewed
Once you are done with your changes, you are ready to get your branch reviewed. This involves three easy steps:
Rebase your branch onto integration/master
It is important to have your branch rebased to be ready for review. Rebasing puts your commits on top of anything else of the branch you are rebasing on, including the changes from that branch. You of course want to rebase onto integration/master. To do that, issue
git rebase integration/master
Be sure to fetch before doing that. At this stage, conflicts might occur: be sure to fix them and commit/push the result. You will be required to force push at this stage.
Push your changes to integration
If you have a KDE developer account, simply
git push integration add-hello-button
from within your add-hello-button branch. If you do not have one, please have your mentor push your branch for you.
Submit the branch for review
Use Reviewboard for getting your branch reviewed. You can read KDE Reviewboard+Git tutorial for getting started.
Getting the branch approved
After your branch has been reviewed and marked as "Ship it!" at least by one of the maintainers of the code you are adding features to, your branch is ready for integration and staging. Your reviewer will inform one of the repository's maintainers of that.
Your work is done at this stage: the maintainer will integrate and stage your branch for you, and will merge it into origin according to the project's merging policy. You will be CCMailed upon every separate step your branch will take on its way to origin/master