[PR #7673/aa7d1a8f backport][3.9] Document release process (#7909)

**This is a backport of PR #7673 as merged into master
(aa7d1a8).**

Co-authored-by: Sam Bull <[email protected]>

docs/contributing-admins.rst

@@ -0,0 +1,57 @@
+:orphan:
+
+Instructions for aiohttp admins
+===============================
+
+This page is intended to document certain processes for admins of the aiohttp repository.
+For regular contributors, return to :doc:`contributing`.
+
+.. contents::
+   :local:
+
+Creating a new release
+----------------------
+
+.. note:: The example commands assume that ``origin`` refers to the ``aio-libs`` repository.
+
+To create a new release:
+
+#. Start on the branch for the release you are planning (e.g. ``3.8`` for v3.8.6): ``git checkout 3.8 && git pull``
+#. Update the version number in ``__init__.py``.
+#. Run ``towncrier``.
+#. Check and cleanup the changes in ``CHANGES.rst``.
+#. Checkout a new branch: e.g. ``git checkout -b release/v3.8.6``
+#. Commit and create a PR. Once PR is merged, continue.
+#. Go back to the release branch: e.g. ``git checkout 3.8 && git pull``
+#. Add a tag: e.g. ``git tag -a v3.8.6 -m 'Release 3.8.6'``
+#. Push the tag: e.g. ``git push origin v3.8.6``
+#. Monitor CI to ensure release process completes without errors.
+
+Once released, we need to complete some cleanup steps (no further steps are needed for
+non-stable releases though). If doing a patch release, we need to do the below steps twice,
+first merge into the newer release branch (e.g. 3.8 into 3.9) and then to master
+(e.g. 3.9 into master). If a new minor release, then just merge to master.
+
+#. Switch to target branch: e.g. ``git checkout 3.9 && git pull``
+#. Start a merge: e.g. ``git merge 3.8 --no-commit --no-ff --gpg-sign``
+#. Carefully review the changes and revert anything that should not be included (most
+   things outside the changelog).
+#. To ensure change fragments are cleaned up properly, run: ``python tools/cleanup_changes.py``
+#. Commit the merge (must be a normal merge commit, not squashed).
+#. Push the branch directly to Github (because a PR would get squashed). When pushing,
+   you may get a rejected message. Follow these steps to resolve:
+
+  #. Checkout to a new branch and push: e.g. ``git checkout -b do-not-merge && git push``
+  #. Open a *draft* PR with a title of 'DO NOT MERGE'.
+  #. Once the CI has completed on that branch, you should be able to switch back and push
+     the target branch (as tests have passed on the merge commit now).
+  #. This should automatically consider the PR merged and delete the temporary branch.
+
+Back on the original release branch, append ``.dev0`` to the version number in ``__init__.py``.
+
+If doing a minor release:
+
+#. Create a new release branch for future features to go to: e.g. ``git checkout -b 3.10 3.9 && git push``
+#. Update ``target-branch`` for Dependabot to reference the new branch name in ``.github/dependabot.yml``.
+#. Delete the older backport label (e.g. backport-3.8): https://github.com/aio-libs/aiohttp/labels
+#. Add a new backport label (e.g. backport-3.10).

docs/contributing.rst

@@ -3,6 +3,8 @@
 Contributing
 ============
 
+(:doc:`contributing-admins`)
+
 Instructions for contributors
 -----------------------------
 

docs/spelling_wordlist.txt

@@ -53,6 +53,7 @@ canonicalize
 cchardet
 cChardet
 ceil
+changelog
 Changelog
 chardet
 Chardet
@@ -88,7 +89,7 @@ Cythonize
 cythonized
 de
 deduplicate
-# de-facto:
+Dependabot
 deprecations
 DER
 dev