shrub/MAINTAINERS.md

Maintainers' Guide

Branch organization

The essence of this branching scheme is that you create "release branches" of independently releasable units of work. These can then be released by their maintainers when ready.

Master branch

Master is what's released on the network. Deployment instructions are in the next section, but tagged releases should always come from this branch.

Feature branches

Anyone can create feature branches. For those with commit access to urbit/urbit, you're welcome to create them in this repo; otherwise, fork the repo and create them there.

Usually, new development should start from master, but if your work depends on work in another feature branch or release branch, start from there.

If, after starting your work, you need changes that are in master, merge it into your branch. If you need changes that are in a release branch or feature branch, merge it into your branch, but understand that your work now depends on that release branch, which means it won't be released until that one is released.

Release branches

Release branches are code that is ready to release. All release branch names should start with release/.

All code must be reviewed before being pushed to a release branch. Thus, feature branches should be PR'd against a release branch, not master.

Create new release branches as needed. You don't need a new one for every PR, since many changes are relatively small and can be merged together with little risk. However, once you merge two branches, they're now coupled and will only be released together -- unless one of the underlying commits is separately put on a release branch.

Here's a worked example. The rule is to make however many branches are useful, and no more. This example is not prescriptive, the developers making the changes may add, remove, or rename branches in this flow at will.

Suppose you (plural, the dev community at large) complete some work in a userspace app, and you put it in release/next-userspace. Separately, you make a small JS change. If you PR it to release/next-userspace, then it will only be released at the same time as the app changes. Maybe this is fine, or maybe you want this change to go out quickly, and the change in release/next-userspace is relatively risky, so you don't want to push it out on Friday afternoon. In this case, put the change in another release branch, say release/next-js. Now either can be released independently.

Suppose you do further work that you want to PR to release/next-userspace, but it depends on your fixes in release/next-js. Simply merge release/next-js into either your feature branch or release/next-userspace and PR your finished work to release/next-userspace. Now there is a one-way coupling: release/next-userspace contains release/next-js, so releasing it will implicitly release release/next-js. However, you can still release release/next-js independently.

This scheme extends to other branches, like release/next-kernel or release/os1.1 or release/ford-fusion. Some branches may be long-lived and represent simply the "next" release of something, while others will have a definite lifetime that corresponds to development of a particular feature or numbered release.

Since they are "done", release branches should be considered "public", in the sense that others may depend on them at will. Thus, never rebase a release branch.

When cutting a new release, you can filter branches with git branch --list 'release/*' or by typing "release/" in the branch filter on Github. This will give you the list of branches which have passed review and may be merged to master and released. When choosing which branches to release, make sure you understand the risks of releasing them immediately. If merging these produces nontrivial conflicts, consider asking the developers on those branches to merge between themselves. In many cases a developer can do this directly, but if it's sufficiently nontrivial, this may be a reviewed PR of one release branch into another.

Non-OTAable release branches

In some cases, work is completed which cannot be OTA'd as written. For example, the code may lack state adapters, or it may not properly handle outstanding subscriptions. It could also be code which is planned to be released only upon a breach (network-wide or rolling).

In this case, the code may be PR'd to a na-release/ branch. All rules are the same as for release branches, except that the code does not need to apply cleanly to an existing ship. If you later write state adapter or otherwise make it OTAable, then you may PR it to a release branch.

Other cases

Outside contributors can generally target their PRs against master unless specifically instructed. Maintainers should retarget those branches as appropriate.

If a commit is not something that goes into a release (eg changes to README or CI), it may be committed straight to master.

If a hotfix is urgent, it may be PR'd straight to master. This should only be done if you reasonably expect that it will be released soon and before anything else is released.

If a series of commits that you want to release is on a release branch, but you really don't want to release the whole branch, you must cherry-pick them onto another release branch. Cherry-picking isn't ideal because those commits will be duplicated in the history, but it won't have any serious side effects.

Hotfixes

Here lies an informal guide for making hotfix releases and deploying them to the network.

Take this PR, as an example. This constituted a great hotfix. It's a single commit, targeting a problem that existed on the network at the time. Here's it should be released and deployed OTA.

If the thing is acceptable to merge, merge it to master

Unless it's very trivial, it should probably have a single "credible looking" review from somebody else on it.

You should avoid merging the PR in GitHub directly. Instead, use the sh/merge-with-custom-msg script -- it will produce a merge commit with message along the lines of:

Merge branch FOO (#PR_NUM)

* FOO:
  bar: ...
  baz: ...

Signed-off-by: SIGNER <signer@example.com>

We do this as it's nice to have the commit log information in the merge commit, which GitHub's "Merge PR" button doesn't do (at least by default). sh/merge-with-custom-msg performs some useful last-minute urbit-specific checks, as well.

You might want to alias sh/merge-with-custom-msg locally, to make it easier to use. My .git/config contains the following, for example:

[alias]
        mu = !sh/merge-with-custom-msg

so that I can type e.g. git mu origin/foo 1337.

Prepare a release commit

You should create Landscape or alternative pill builds, if or as appropriate (i.e., if anything in Landscape changed -- don't trust any compiled JS/CSS that's included in the commit), and commit these in a release commit.

You should always create a solid pill, in particular, as it's convenient for tooling to be able to boot directly from a given release.

If you're making a Vere release, just play it safe and update all the pills.

Tag the resulting commit

What you should do here depends on the type of release being made.

First, for Urbit OS releases:

If it's a very trivial hotfix that you know isn't going to break anything, tag it as urbit-os-vx.y.z. Here 'x' refers to the product version (e.g. OS1, OS2..), 'y' to the continuity era in that version, and 'z' to an OTA patch counter. So for a hotfix version, you'll just want to increment 'z'.

Use an annotated tag, i.e.

git tag -a urbit-os-vx.y.z

The tag format should look something like this:

urbit-os-vx.y.z

This release will be pushed to the network as an over-the-air update.

Release notes:

  [..]

Contributions:

  [..]

You can get the "contributions" section by the shortlog between the last release and this release:

git log --pretty=short LAST_RELEASE.. | git shortlog

I originally tried to curate this list somewhat, but now just paste it verbatim. If it's too noisy, yell at your colleagues to improve their commit messages.

Try to include a high-level summary of the changes in the "release notes" section. You should be able to do this by simply looking at the git log and skimming the commit descriptions (or perhaps copying some of them in verbatim). If the commit descriptions are too poor to easily do this, then again, yell at your fellow contributors to make them better in the future.

If it's not a trivial hotfix, you should probably make any number of release candidate tags (e.g. urbit-os-vx.y.z.rc1, urbit-os-vx.y.z.rc2, ..), test them, and after you confirm one of them is good, tag the release as urbit-os-vx.y.z.

For Vere releases:

Tag the release as urbit-vx.y.z. The tag format should look something like this:

urbit-vx.y.z

Note that this Vere release will by default boot fresh ships using an Urbit OS
va.b.c pill.

Release binaries:

(linux64)
https://bootstrap.urbit.org/urbit-vx.y.z-linux64.tgz

(macOS)
https://bootstrap.urbit.org/urbit-vx.y.z-darwin.tgz

Release notes:

  [..]

Contributions:

  [..]

The same schpeel re: release candidates applies here.

Note that the release notes indicate which version of Urbit OS the Vere release will use by default when booting fresh ships. Do not include implicit Urbit OS changes in Vere releases; this used to be done, historically, but shouldn't be any longer. If there are Urbit OS and Vere changes to be released, make two separate releases.

Deploy the update

(Note: the following steps are automated by some other Tlon-internal tooling. Just ask ~nidsut-tomdun for details.)

For Urbit OS updates, this means copying the files into ~zod's %base desk. The changes will be synced to /~zod/kids and then propagated through other galaxies and stars to the rest of the network.

For consistency, I create a release tarball and then rsync the files in.

$ wget https://github.com/urbit/urbit/archive/urbit-os-vx.y.z.tar.gz
$ tar xzf urbit-os-vx.y.z.tar.gz
$ herb zod -p hood -d "+hood/mount /=base="
$ rsync -zr --delete urbit-urbit-os-vx.y.z/pkg/arvo/ zod/base
$ herb zod -p hood -d "+hood/commit %base"

For Vere updates, this means simply shutting down each desired ship, installing the new binary, and restarting the pier with it.

Announce the update

Post an announcement to urbit-dev. The tag annotation, basically, is fine here -- I usually add the %base hash (for Urbit OS releases) and the release binary URLs (for Vere releases). Check the urbit-dev archives for examples of these announcements.