META: Renaming "master" to "main"

[felixvd]

Sooner or later this topic will come up here. We might as well summarize the discussion before we are blindsided in a maintainer meeting working group meeting and end up wasting time.

Summary

There is a discussion about the use of "master/slave" terminology in tech. The branch name "main" is considered preferable to "master". Shall we switch?

Regardless of the controversy, "main" is likely a better branch name than "master" (the original author thinks so), particularly in our use case (it is the active dev branch, not the copy of record). I don't know that it is worth the effort of changing, but to have an idea of what it entails, I had a quick look around.

What would need to be changed?

Assuming we add a main branch and keep master around:

• Add a main branch of the ros-planning repositories and change their default branch setting on Github
• Change a few mentions in MIGRATION.md, codecov.yaml and on the website
• Change the references in the Dockerfiles in moveit and a few Travis references in moveit_ci
• Decide what to do about the master-source, master-ci, master-experimental docker images
• Rename the branch in local clones

Deleting the master branch (or renaming it to main) would affect .rosinstall settings etc. of downstream users, so that isn't tractable without at least 12 months notice. Adding main as the default branch and keeping master on life support does not seem to be intrusive or difficult, but does require effort.

Is it worth it?

I don't know, I just wanted to compile the information. We have added a code of conduct before to be more inclusive, but that did not come with any technical consequences, whereas this does. If I was forced to make a choice, I would probably vote "If someone wants to take care of it, go for it".

[rhaschke]

I think we should postpone this discussion to the point when git decides to rename its default branch. Let's focus on real development. I never even thought of a connotation with slavery.

[v4hn]

sigh agreed.

[gavanderhoorn]

If I've learned anything the past few days (and judging by my inbox I've had plenty of input/help there): @rhaschke: it doesn't matter what your understanding of a word is, or which associations it comes with for you -- this is about other people. I would recommend to read this comment by Bill Smart on the discussion @felixvd references to get an idea of the state of affairs and sensitivity of this subject.

This is about perception and emotion, not a technical discussion (I would almost say there are no technical merits on which this can be discussed, so don't try).

I'm still not sure I understand how this will scale, but that's not the point here.

[v4hn]

it doesn't matter what your association with a word is.

Indeed. As already Lewis Carroll made us understand in Humpty Dumpty's famous "When *I* use a word" quote.

This is about perception and emotion, not a technical discussion.

As with all change-here-to-be-inclusive debates there is only one way forward and I am convinced no maintainer directly opposes the change as long as everything is changed consistently.

[davetcoleman]

just seeing this thread

I've been following this trend in tech and the other threads in the ROS community and I agree with @felixvd that it is inevitable. I agree with @gavanderhoorn there are no technical merits, and I too really liked Bill Smart's write-up @wdsmart.

I propose we don't change anything in MoveIt 1 since it will soon be deprecated anyway and is a fair amount of effort, but we should do the full switch to the "main" branch naming in MoveIt 2 while there are still very few adopters. I believe Open Robotics said something to that effect also.

My personal belief: the BLM movement is very important in the US and elsewhere, and I support it. I do think there are many more significant and pressing issues than the "master" branch naming that we, as a community, need to address regarding systemic racism and diversity, particularly in an open source community. I am worried that this semantic naming change is a distraction and excuse to claim progress without engaging in real issues.

That said, let's switch to using a "main" branch with MoveIt 2 as a first step.

[davetcoleman]

moveit 2 is now using "main" as its default branch:
https://github.com/ros-planning/moveit2

I think this issue can be closed.