Workflow for Maintainers

This page is for maintainers — those of us who merge our own or other peoples’ changes into the upstream repository.

Being as how you’re a maintainer, you are completely on top of the basic stuff in How to make a code contribution.

Integrating changes manually

First, check out the astropy repository. The instructions in Tell git where to look for changes in the development version of Astropy add a remote that has read-only access to the upstream repo. Being a maintainer, you’ve got read-write access.

It’s good to have your upstream remote have a scary name, to remind you that it’s a read-write remote:

git remote add upstream-rw
git fetch upstream-rw --tags

Let’s say you have some changes that need to go into trunk (upstream-rw/main).

The changes are in some branch that you are currently on. For example, you are looking at someone’s changes like this:

git remote add someone
git fetch someone
git branch cool-feature --track someone/cool-feature
git checkout cool-feature

So now you are on the branch with the changes to be incorporated upstream. The rest of this section assumes you are on this branch.

A few commits

If there are only a few commits, consider rebasing to upstream:

# Fetch upstream changes
git fetch upstream-rw

# Rebase
git rebase upstream-rw/main

Remember that, if you do a rebase, and push that, you’ll have to close any github pull requests manually, because github will not be able to detect the changes have already been merged.

A long series of commits

If there are a longer series of related commits, consider a merge instead:

git fetch upstream-rw
git merge --no-ff upstream-rw/main

The merge will be detected by github, and should close any related pull requests automatically.

Note the --no-ff above. This forces git to make a merge commit, rather than doing a fast-forward, so that these set of commits branch off trunk then rejoin the main history with a merge, rather than appearing to have been made directly on top of trunk.

Check the history

Now, in either case, you should check that the history is sensible and you have the right commits:

git log --oneline --graph
git log -p upstream-rw/main..

The first line above just shows the history in a compact way, with a text representation of the history graph. The second line shows the log of commits excluding those that can be reached from trunk (upstream-rw/main), and including those that can be reached from current HEAD (implied with the .. at the end). So, it shows the commits unique to this branch compared to trunk. The -p option shows the diff for these commits in patch form.

Push to trunk

git push upstream-rw my-new-feature:main

This pushes the my-new-feature branch in this repository to the main branch in the upstream-rw repository.

Fixing coding style issues

Astropy now uses the bot to assist with maintaining the astropy coding style and fixing code style issues. The bot makes use of the pre-commit hook described in detail in Pre-commit.

By default the bot will run a code-style check on every push to a pull request with the results reported in the checks section of the pull request. The bot will skip running its check if a commit message contains [skip ci], [ci skip], [skip], or [ skip].

One can control the bot by making comments on the pull request:

  • To trigger a re-run of the code-style check, comment on the PR with: run
  • To have the bot push a commit to the PR fixing the code-style issues (the ones that can be fixed by automated tools), comment on the PR with: autofix


These comments must appear in the comment on a single line by themselves.


If you wish to run the pre-commit check first in CI without running Actions, use [skip actions] or [actions skip] in your commit message.

Using Milestones and Labels

General guidelines for milestones:

  • 100% of pull requests should have a milestone

  • Issues are not milestoned unless they block a given release

  • Only the following criteria should result in a pull request being closed without a milestone:

    • Invalid (user error, etc.)

    • Duplicate of an existing pull request

    • A pull request superseded by a new pull request providing an alternate implementation

  • In general there should be the following open milestones:

    • The next bug fix releases for any still-supported version lines; for example if 0.4 is in development and 0.2.x and 0.3.x are still supported there should be milestones for the next 0.2.x and 0.3.x releases.

    • The next X.Y release, i.e. the next minor release; this is generally the next release that all development in main is aimed toward.

    • The next X.Y release +1; for example if 0.3 is the next release, there should also be a milestone for 0.4 for issues that are important, but that we know won’t be resolved in the next release.

  • We have Rolling reminder: update wcslib and cfitsio and leap second/IERS B table to the latest version. The milestone for this issue should be updated as part of the release procedures.

General guidelines for labels:

  • Issues: Maintainer should be proactive in labeling issues as they come in. At the very least, label the subpackage(s) involved and whether the issue is a bug.

  • Pull requests: We have GitHub Actions to automatically apply labels using some simple rules when a pull request is opened. Once that is done, a maintainer can then manually apply any other labels that apply.

Updating and Maintaining the Changelog

The Astropy “changelog” is managed with towncrier, which is used to generate the CHANGES.rst file at the root of the repository. The changelog fragment files should be added with each PR as described in docs/changes/README.rst. The purpose of this file is to give a technical, but still user (and developer) oriented overview of what changes were made to Astropy between each public release. The idea is that it’s a little more to the point and easier to follow than trying to read through full git log. It lists all new features added between versions, so that a user can easily find out from reading the changelog when a feature was added. Likewise it lists any features or APIs that were changed (and how they were changed) or removed. It also lists all bug fixes. Affiliated packages are encouraged to maintain a similar changelog.

Stale Policies

The astropy GitHub repository has the following stale policies, which are enforced by action-astropy-stalebot in .github/workflows/stalebot.yml that runs on a schedule. Hereafter, we refer to this automated enforcer as stale-bot.

All the timing mentioned depends on a successful stale-bot run. GitHub API limits, spam protection, or server maintenance could affect the run. The former might especially be relevant when there is a significant backlog of stale issues and pull requests accumulated.

If you notice unintended stale-bot behaviors, please report them to the Astropy maintainers.


A maintainer applies the “Closed?” label to mark an issue as stale, otherwise it stays open until someone manually closes it. Once marked as stale, a warning will be issued.

A maintainer can apply “keep-open” label or remove “Closed?” label to remove the stale status. Otherwise, stale-bot will close the issue after about a week and apply a “closed-by-bot” label.

When both “keep-open” and “Close?” labels exist, the former will take precedence and the latter will be removed from the issue.

Pull Requests

A pull request becomes stale after about 4-5 months since the last commit (stale-bot counts in seconds and naively assumes 30 days per month). When this happens, stale-bot applies the “Close?” label to it. A maintainer can also fast-track its staleness by manually applying the “Close?” label. Once marked as stale, a warning will be issued.

A maintainer can apply “keep-open” label or remove “Closed?” label to remove the stale status. The pull request author (or maintainer) can reset the stale timer by pushing out a commit (e.g., by rebasing). Otherwise, stale-bot will close the pull request after about a month and apply a “closed-by-bot” label.


The “keep-open” label should be used very sparingly, only for pull requests that must be kept open. For example, a pull request that has been completed but cannot be merged until a blocker is removed can use this label. An abandoned or incomplete pull request should not use this label as it can be re-opened later when the author has a renewed interest to wrap it up.

When both “keep-open” and “Close?” labels exist, the former will take precedence and the latter will be removed from the pull request. If maintainer removes “Close?” without applying “keep-open” or pushing a new commit, stale-bot will mark it as stale again in the next run.

If a new commit is pushed but the “Close?” label remains, stale-bot will close it without another warning after another 4-5 months.

In short, to truly reset the stale timer for a pull request, it is recommended that a new commit be pushed and the “Close?” label be removed.