How to make a new release of ``skimage``
========================================

While following this guide, note down all the times that you need to
consult a previous release manager, or that you find an instruction
unclear. You will, of course, make a PR to update these notes after
you are done with the release! ;-)

Before you start, make sure you have all the required write
permissions (if not, you will need to ask an owner to grant you
access), specifically to:

  - https://pypi.org/project/scikit-image/
  - https://github.com/scikit-image/scikit-image-web


- Check ``TODO.txt`` for any outstanding tasks.

We use a variant of "semantic versioning", where version numbers are classified
as v<major>.<minor>.<patch>.  By default, releases are made from the main
branch as part of a linear release history and, as described below, are
triggered by pushing a git tag to the scikit-image repository on github.  If
a patch release is required for an older version, a branch can be created from
the appropriate point in main and the following instructions are still apt.

- Update the release notes (note this will soon change with the addition of
  Towncrier integrated directly into the CI):

  1. Review and cleanup ``doc/release/release_dev.rst``.

  2. Make a list of merges, contributors, and reviewers by running
     ``tools/generate_release_notes.py -h`` and following that file's usage.

  3. Paste this list at the end of the ``release_dev.txt``.

  4. Scan the PR titles for highlights, deprecations, API changes,
     and bugfixes, and mention these in the relevant sections of the notes.
     Try to present the information in an expressive way by mentioning
     the affected functions, elaborating on the changes and their
     consequences. If possible, organize semantically close PRs in groups.

  5. Check for duplicate names in the automatically generated list of
     contributors and reviewers

  6. Rename the file to ``doc/release/release_<major>.<minor>.txt``

  7. Copy ``doc/release/release_template.txt`` to
     ``doc/release/release_dev.txt`` for the next release.

  8. Copy relevant deprecations from ``release_<major>_<minor>.txt``
     to ``release_dev.txt``.

  9. Update the file ``skimage/data/_fetchers.py`` to point the pooch
     repository to the new branch instead of main during testing.
     Look for the parameter ``version_dev="main",`` for ``pooch.create`` and
     change it to the newly created branch name.

- Submit the release notes for review by other project maintainers:

  - Create a PR from v<major>.<minor>.x branch to `main` (at this point,
    the difference should show the full contents of the release notes).
  - Discuss with others, and make the changes directly to v<major>.<minor>.x branch.
  - Once the consensus is found, ask the project maintainers to merge
    the PR.
  - Cherry pick the change onto the release branch.

- On the main branch, update the version number in ``skimage/__init__.py``
  to the next ``.dev0`` version, commit, and push. This should follow PEP440
  meaning that the appropriate version number would look something like
  ``0.20.0.dev0`` with the period between ``0`` and ``dev`` and a trailing
  ``0`` immediately after ``dev``. The final ``0`` is necessary to ensure
  that
  `NumpyVersion <https://github.com/scikit-image/scikit-image/pull/4947>`_
  correctly interprets the version number.

- To debug building and testing wheels via CI, push to a branch named
  `maintenance/anything`.

  Once everything works as intended, remove those branches and proceed.

- Edit ``doc/source/_static/docversions.js`` in order to
  add the release, e.g., `0.15.x`, and commit.

- Update the version number to stable in ``skimage/__init__.py``, and commit.

- Make a release. You may wish to iterate initially with release candidates in
  the steps below (add rc along with a number to the end of the tag version).

  1. Add the version number as a tag in git::

   git tag -s -m <github_release_message> [-u <key-id>] v<major>.<minor>.0

  (If you do not have a GPG key, follow the tutorial to set it up:
   https://help.github.com/articles/signing-commits-with-gpg/)

  2. Push the new tag to GitHub::

   git push upstream v<major>.<minor>.<patch>

  (where ``upstream`` is the name of the
   ``github.com:scikit-image/scikit-image`` repository.)

  Pushing the version tag will (for details see .github/workflows/wheel_tests_and_release.yml):

    1. Build and upload the wheels to PyPI

    2. Publish the source distribution on PyPi

    3. Publish the release on github

- Once the release is completed you should update the release docs:
  - Edit ``doc/source/_static/docversions.js`` and commit
  - On the release branch, build a clean version of the docs. In the
    root directory, run ``pip install .``.
  - In the ``doc/`` directory:
    - Build using
      ``make clean; make html; make gh-pages``.
    - Check (since this a new feature) that binder links in gallery examples
      point to the release branch, e.g. `0.16.x`.
    - In the ``gh-pages/`` directory:
      - Update the symlink to ``stable`` and commit.
      - Upload the docs: ``git push origin gh-pages`` in ``doc/gh-pages``.

- Update the web frontpage:

  The webpage source is kept in a separate repo: `scikit-image-web`.

  - Add release date to ``index.rst`` under "News".
  - Add previous stable version documentation path to disallowed paths
    in `robots.txt`
  - Commit and push (this will also build and update the website).

- Post release notes on user & dev forums, blog, Twitter, etc.

  - https://forum.image.sc/tag/scikit-image
  - https://discuss.scientific-python.org/c/contributor/skimage
  - scipy-user@python.org
  - scikit-learn@python.org

- Update the version and the release date on Wikipedia
  https://en.wikipedia.org/wiki/Scikit-image

- Make a PR to scikit-image with any updates you might have to these notes

- If making a patch release (v<major>.<minor>.<patch>), forward-port the
  release notes to the main branch and make a PR.

Conda-forge
-----------

**Note**: conda-forge now has an automated bot who makes the below PR for you.
Now all you have to do is to look at pull requests at
https://github.com/conda-forge/scikit-image-feedstock/pulls
and check for a new one for this version. Wait for all the continuous
integration checks to go green, then merge.

The manual instructions remain below in case the bot fails for some reason.

A scikit-image build recipe resides at
https://github.com/conda-forge/scikit-image-feedstock. You should update it to
point to the most recent release. You can do this by following these steps:

- Fork the repository at https://github.com/conda-forge/scikit-image-feedstock,
  and clone it to your machine.
- Sprout a new branch, e.g. ``v<major>.<minor>``.
- Find out the SHA256 hash of the source distribution. You can find this at
  https://pypi.org/project/scikit-image/, or use the following commands:

  - ``sha256sum path/to/scikit-image-*.tar.gz`` (Linux)
  - ``shasum -a 256 dist/scikit-image-*.tar.gz`` (macOS)
  - ``CertUtil -hashfile dist\scikit-image-*.tar.gz SHA256`` (Windows)

- Edit the file ``recipe/meta.yaml``:

  - Update the version number on the first line.
  - Update the SHA256 value on line 9.
  - If necessary, reset the build number to 0. (line 12)
  - Update any requirements in the appropriate sections (build or run).
    Note: don't remove ``numpy x.x``. This tells conda-smithy, conda-forge's
    build system, that the library must be linked against NumPy at build time.
  - Commit these changes.
  - Update the infrastructure around the recipe with ``conda-smithy``:
    * Install conda-smithy either with conda or pip
    * Run ``conda-smithy rerender`` in the root of the repository, and commit
      the changes.

- Push to your fork, and submit a pull request to the
  upstream repo.

Debian
------

The below instructions remain here for completeness. However, the Debian
scientific team has kindly taken over package maintenance. Simply follow the
procedure described at https://www.debian.org/Bugs/Reporting to report a "bug"
that there is a new version of scikit-image out (specifying the version
number), with severity set to "Wishlist".

If you want to take matters into your own hands for some reason, follow the
instructions detailed below to cut a Debian release yourself.

- Tag the release as per instructions above.
- git checkout debian
- git merge v0.x.x
- uscan <- not sure if this step is necessary
- Update changelog (emacs has a good mode, requires package dpkg-dev-el)
  - C-C C-v add new version, C-c C-c timestamp / save
- git commit -m 'Changelog entry for 0.x.x'
- git-buildpackage -uc -us -rfakeroot
- Sign the changes: debsign skimage_0.x.x-x_amd64.changes
- cd ../build-area && dput mentors skimage_0.x.x-x_amd64.changes
- The package should now be available at:

  http://mentors.debian.net/package/skimage

For the last lines above to work, you need ``~/.gbp.conf``::

  [DEFAULT]
  upstream-tag = %(version)s

  [git-buildpackage]
  sign-tags = True
  export-dir = ../build-area/
  tarball-dir = ../tarballs/

As well as ``~/dput.cf``::

  [mentors]
  fqdn = mentors.debian.net
  incoming = /upload
  method = http
  allow_unsigned_uploads = 0
  progress_indicator = 2
  # Allow uploads for UNRELEASED packages
  allowed_distributions = .*
