CodeIgniter4/contributing/workflow.md

Contribution Workflow
=====================

Much of the workflow for contributing to CodeIgniter (or any project)
involves understanding how [Git](https://git-scm.com/) is used to manage
a shared repository and contributions to it. Examples below use the Git
bash shell, to be as platform neutral as possible. Your IDE may make
some of these easier.

Some conventions used below, which you will need to provide appropriate
values for when you try these:

    ALL_PROJECTS    // folder location with all your projects in subfolders, eg /lampp/htdocs
    YOUR_PROJECT    // folder containing the project you are working on, inside ALL_PROJECTS
    ORIGIN_URL      // the cloning URL for your repository fork
    UPSTREAM_URL    // the cloning URL for the CodeIgniter4 repository

Branching
---------

CodeIgniter uses the
[Git-Flow](http://nvie.com/posts/a-successful-git-branching-model/)
branching model, which requires all pull requests to be sent to the
"develop" branch. This is where the next planned version will be
developed. The "master" branch will always contain the latest stable
version and is kept clean so a "hotfix" (e.g: an emergency security
patch) can be applied to master to create a new version, without
worrying about other features holding it up. For this reason, all
commits need to be made to "develop" and any sent to "master" will be
closed automatically. If you have multiple changes to submit, please
place each change into their own branch on your fork.

One thing at a time: a pull request should only contain one change. That
does not mean only one commit, but one change - however many commits it
took. The reason for this is that if you change X and Y but send a
single pull request for both at the same time, we might really want X
but disagree with Y, meaning we cannot merge the request. Using the
Git-Flow branching model you can create new branches for both of these
features and send two requests.

Forking
-------

You work with a fork of the CodeIgniter4 repository. This is a copy of
our repository, in your GitHub account. You can make changes to your
forked repository, while you cannot do the same with the shared one -
you have to submit pull requests to it instead.

[Creating a fork](https://help.github.com/articles/fork-a-repo/) is done
through the GitHub website. Navigate to [our
repository](https://github.com/codeigniter4/CodeIgniter4), click the
**Fork** button in the top-right of the page, and choose which account
or organization of yours should contain that fork.

Cloning
-------

You *could* work on your repository using GitHub's web interface, but
that is awkward. Most developers will clone their repository to their
local system, and work with it there.

On GitHub, navigate to your forked repository, click **Clone or
download**, and copy the cloning URL shown. We will refer to this as
ORIGIN\_URL.

Clone your repository, leaving a local folder for you to work with:

    cd ALL_PROJECTS
    git clone ORIGIN_URL

Synching develop
----------------

Within your local repository, Git will have created an alias,
**origin**, for the GitHub repository it is bound to. You want to create
an alias for the shared repository as well, so that you can "synch" the
two, making sure that your repository includes any other contributions
that have been merged by us into the shared repo:

    git remote add upstream UPSTREAM_URL

Then synchronizing is done by pulling from us and pushing to you. This
is normally done locally, so that you can resolve any merge conflicts.
For instance, to synchronize **develop** branches:

    git checkout develop
    git pull upstream develop
    git push origin develop

You might get merge conflicts when you pull from upstream. It is your
responsibility to resolve those locally, so that you can continue
collaborating with the shared repository. Basically, the shared
repository is updated in the order that contributions are merged into
it, not in the order that they might have been submitted. If two PRs
update the same piece of code, then the first one to be merged will take
precedence, even if it causes problems for other contributions.

It is a good idea to synchronize repositories when the shared one
changes.

Branching Revisited
-------------------

The top of this page talked about the **master** and **develop**
branches. The *best practice* for your work is to create a *feature
branch* locally, to hold a group of related changes (source, unit
testing, documentation, change log, etc).

This local branch should be named appropriately, for instance
"fix/problem123" or "new/mind-reader". The slashes in these branch names
is optional, and implies a sort of namespacing if used.

For instance, make sure you are in the *develop* branch, and create a
new feature branch, based on *develop*, for a new feature you are
creating:

    git checkout develop
    git checkout -b new/mind-reader

Saving changes only updates your local working area.

Committing
----------

Your local changes need to be *committed* to save them in your local
repository. This is where [contribution signing](./signing.md) comes
in.

You can have as many commits in a branch as you need to "get it right".
For instance, to commit your work from a debugging session:

    git add .
    git commit -S -m "Find and fix the broken reference problem"

Just make sure that your commits in a feature branch are all related.

If you are working on two features at a time, then you will want to
switch between them to keep the contributions separate. For instance:

    git checkout new/mind-reader
    // work away
    git add .
    git commit -S -m "Added adapter for abc"
    git checkout fix/issue-123
    // work away
    git add .
    git commit -S -m "Fixed problem in DEF\Something"
    git checkout develop

The last checkout makes sure that you end up in your *develop* branch as
a starting point for your next session working with your repository.
This is a good practice, as it is not always obvious which branch you
are working in.

Pushing Your Branch
-------------------

At some point, you will decide that your feature branch is complete, or
that it could benefit from a review by fellow developers.

**Note:**
> Remember to synch your local repo with the shared one before pushing!
It is a lot easier to resolve conflicts at this stage.


Synchronize your repository:

    git checkout develop
    git pull upstream develop
    git push origin develop

Bring your feature branch up to date:

    git checkout new/mind-reader
    git merge develop

And finally push your local branch to your GitHub repository:

    git push origin new/mind-reader

Pull Requests
-------------

On GitHub, you propose your changes one feature branch at a time, by
switching to the branch you wish to contribute, and then clicking on
"New pull request".

Make sure the pull request is for the shared **develop** branch, or it
may be rejected.

Make sure that the PR title is helpful for the maintainers and other
developers. Add any comments appropriate, for instance asking for
review.


**Note:**
> If you do not provide a title or description for your PR, the odds of it being summarily rejected
rise astronomically.

When your PR is submitted, a continuous integration task will be
triggered, running all the unit tests as well as any other checking we
have configured for it. If the unit tests fail, or if there are merge
conflicts, your PR will not be mergeable until those are fixed.

Fix such changes locally, commit them properly, and then push your
branch again. That will update the PR automatically, and re-run the CI
tests. You don't need to raise a new PR.

If your PR does not follow our contribution guidelines, or is
incomplete, the codebase maintainers will comment on it, pointing out
what needs fixing.

Cleanup
-------

If your PR is accepted and merged into the shared repository, you can
delete that branch in your GitHub repository as well as locally.