Add support for Mercurial repositories?

[paugier]

Proposed change

In mybinder.org, add a new choice to specify a repository just after "Git repository": "Mercurial repository".

Then, the information to give would be very similar than for the case "Git repository":

• "Arbitrary hg repository URL (http://hg.example.com/repo)"
• hg branch, tag, topic, bookmark or commit SHA

Who would use this feature?

Mercurial users.

One may argue that monopoly in version control is pretty bad for versioning and open-source. Without Git challenger, versioning is not as good as it could be. For example, Mercurial community (people at Facebook) invented the command absorb which is really useful and I guess Git will get something similar someday.

Mercurial is still alive, with good corporate usage and an active community. The Gitlab fork supporting Mercurial (Heptapod, used for example by PyPy) will soon reach its 1.0 version.

(Optional): Suggest a solution

The implementation for MyBinder should be quite simple : tiny changes in the website, one variable about the kind of repo (git or hg), few diff for the hg commands.

[welcome]

Thank you for opening your first issue in this project! Engagement like this is essential for open source projects! 🤗

If you haven't done so already, check out Jupyter's Code of Conduct. Also, please try to follow the issue template as it helps other other community members to contribute more effectively.

You can meet the other Jovyans by joining our Discourse forum. There is also an intro thread there where you can stop by and say Hi! 👋

Welcome to the Jupyter community! 🎉

[manics]

The backend of Binderhub is repo2docker which supports multiple content-providers, you can see the current ones here:
https://www.github.com/jupyterhub/repo2docker/tree/master/repo2docker%2Fcontentproviders
I think this is where the bulk of the work has to happen.

If Mercurial is added there then BinderHub can be updated to offer it.

Is this something you're interested in working on?

[paugier]

Is this something you're interested in working on?

Great, it's in Python! I'm going to have a look at it. Thanks for the link.

[paugier]

Mercurial support has now landed in master of repo2docker 🙂

I guess the next steps would be (i) wait for a new release of repo2docker (?) and (ii) a PR similar to #1100 but for Mercurial repositories.

I don't know JS but if it is as simple as that, it seems doable.

Is there something else to do? Any advice / suggestions?

[manics]

You don't need to wait for a repo2docker release, all updates are pushed to Docker Hub https://hub.docker.com/r/jupyter/repo2docker/tags and you can also install it from the master branch.

I'm not sure of the exact steps to add a provider to BinderHub, but there are some docs here: https://binderhub.readthedocs.io/en/latest/developer/repoproviders.html#adding-a-new-repository-provider