Typical workflow for contributing to a public GitHub project, demonstrating the use of branches and remotes. For this demonstration, I'll use a GitHub project I've been contributing to recently – https://github.com/containers/libpod – which is the source of the Docker lookalike podman command (among other things).

Unsurprisingly, if you don't already have a GitHub account, get one – examples that follow will refer to my GitHub account rpjday.

As a first step, over at GitHub, you need to “fork” the public project of interest – in this case, the public project containers/libpod will be forked to a copy that I will own (also residing at GitHub), rpjday/libpod, and here's the secret of the GitHub workflow.

Once you create your personal fork of that public project containers/libpod, you will not update that personal copy from the public version, nor will you pull from your personal fork; rather, your personal fork will be used as the destination to which you push branches with changes from your local machine that you will ask the containers/libpod maintainers to pull from via “pull requests”.

So go ahead and create that personal GitHub fork before going any further.

Once you've made that personal GitHub fork (agin, in my case, rpjday/libpod), you need to make one more copy of the repository – this one will be clone of your personal fork to your local machine, which represents the working tree in which you create new branches and make local changes that you'll push to your GitHub fork for eventual incorporation into the public project, but here's the trick for clarity.

Since you'll (shortly) be working with two remotes for this workflow, when you clone your personal fork, select a remote name other than the default of origin – I'll use the remote name of rpjday to clearly identify that this is the remote corresponding to my personal fork over at GitHub, not the public project:

$ mkdir podman/libpod
$ cd podman/libpod
$ git clone https://github.com/rpjday/libpod git

Verify that everything here is up to date with your GitHub fork:

$ cd git
$ git status
On branch master
Your branch is up-to-date with 'rpjday/master'.

nothing to commit, working tree clean
$

In addition, you can verify that your local clone has one registered remote – your personal GitHub fork with remote name rpjday:

$ git remote -v
rpjday	https://github.com/rpjday/libpod.git (fetch)
rpjday	https://github.com/rpjday/libpod.git (push)
$

Again, keep in mind that this remote is where you will push your intended contributions to the public project.

In addition to the remote for your personal fork, you need to register a second remote representing the public project, as this is where you'll pull new content from, including any of your pull requests that are accepted and merged into the public master branch.

Again, for clarity, choose a remote name other than the default of origin – I like to use the project name itself (in this case, libpod):

$ git remote add libpod https://github.com/containers/libpod
$

You can now verify that your local clone has two registered remotes – one for pulling new content added to the public project (libpod, and the second your personal remote for pushing changes (rpjday):

$ git remote -v
libpod	https://github.com/containers/libpod (fetch)
libpod	https://github.com/containers/libpod (push)
rpjday	https://github.com/rpjday/libpod.git (fetch)
rpjday	https://github.com/rpjday/libpod.git (push)
$

You can see this information in your .git/config file:

$ cat .git/config
[core]
	repositoryformatversion = 0
	filemode = true
	bare = false
	logallrefupdates = true
[remote "rpjday"]
	url = https://github.com/rpjday/libpod.git
	fetch = +refs/heads/*:refs/remotes/rpjday/*
[branch "master"]
	remote = rpjday
	merge = refs/heads/master
[remote "libpod"]
	url = https://github.com/containers/libpod
	fetch = +refs/heads/*:refs/remotes/libpod/*
$

Even as you're working on contributions to the public project, there is undoubtedly new content being merged into its master branch from others, and you probably want to keep up with that new content in case you need to rebase any of your work on top of it.

First, you can, as often as you like, fetch from the upstream (public project) libpod remote into your remote tracking branch libpod/master with:

$ git fetch libpod

Occasionally, you might want to merge that new content into your local master branch in case you need to do any local rebasing:

$ git checkout master
$ git merge libpod/master

Finally, whenever you update your local master branch, you should push it to your personal fork (which is how your personal fork at GitHub gets updated):

$ git push rpjday master

Do all of this on a regular basis to keep everything in sync.

Contributing changes to the main project involves three steps:

• Make and commit some local changes (preferably on a feature branch).
• Push those changes (that branch) to your GitHub fork.
• Make a “pull request” to have the main project accept your commit(s) on that branch.

First, create a new branch, make and commit a silly change:

$ git checkout -b topic/rpjday/issue42
Switched to a new branch 'topic/rpjday/issue42'
$

Make a simple change to README.asc and commit it:

$ git checkout -b topic/rpjday/issue42
Switched to a new branch 'topic/rpjday/issue42'
$

$ git commit -a -m "fix issue42"
[topic/rpjday/issue42 77fad5f] topic/rpjday/issue42
 1 file changed, 1 insertion(+), 1 deletion(-)
$

$ git show
commit 77fad5f0aadd229628baa7811b0b49c7580d96f0 (HEAD -> topic/rpjday/issue42)
Author: Robert P. J. Day <rpjday@crashcourse.ca>
Date:   Wed Feb 14 07:06:42 2018 -0500

    fix issue42

diff --git a/README.asc b/README.asc
index d7810fd..126bfd4 100644
--- a/README.asc
+++ b/README.asc
@@ -1,4 +1,4 @@
-= Pro Git, Second Edition
+= Pro Git, Second Edition (rday change)
 
 Welcome to the second edition of the Pro Git book.
 
$

At this point, you can push this new branch to your GitHub fork:

$ git push origin topic/rpjday/issue42

Provided you're logged into your account at GitHub, you'll suddenly see the appearance of a new branch sillyb. If you think it's ready to go, you can select “Compare & pull request” to examine and confirm that you want to hand that off to the main project.

If all goes well and your change is accepted and committed, you will have to perform the two earlier steps to fetch and merge your changes into your local clone into the master branch:

$ git fetch progit
$ git merge progit/master

In addition, you can now delete the sillyb branch if you have no further use for it.