Release Zarr-Python v3.1.0

[d-v-b]

Release: v3.1.0
Scheduled Date: 2025/07/14

Priority PRs/issues to complete prior to release

• Priority pull request #X

Before release:

• Make sure that all pull requests which will be included in the release have been properly documented as changelog files in the changes/ directory.
• Run towncrier build --version x.y.z to create the changelog, and commit the result to the main branch.
• Check SPEC 0 to see if the minimum supported version of Python or NumPy needs bumping.
• Check to ensure that:
  • Deprecated workarounds/codes/tests are removed. Run grep "# TODO" **/*.py to find all potential TODOs.
  • All tests pass in the "Tests" workflow.
  • All tests pass in the "GPU Tests" workflow.
  • All tests pass in the "Hypothesis" workflow.
  • Check that downstream libraries work well (maintainers can make executive decisions about whether all checks are required for this release).
    • Xarray (@jhamman @dcherian @TomNicholas)
      • Zarr's upstream compatibility is tested via the Upstream Dev CI worklow.
      • Click on the most recent workflow and check that the upstream-dev job has run and passed. upstream-dev is not run on all all workflow runs.
      • Check that the expected version of Zarr-Python was tested using the Version Info step of the upstream-dev job.
      • If testing on a branch other than main is needed, open a PR modifying https://github.com/pydata/xarray/blob/90ee30943aedba66a37856b2332a41264e288c20/ci/install-upstream-wheels.sh#L56 and add the run-upstream label.
    • Titiler.Xarray (@maxrjones)
      • Modify dependencies for titiler.xarray.
      • Modify triggers for running the test workflow.
      • Push the branch to the repository and check for the actions for any failures.

Release:

• Go to https://github.com/zarr-developers/zarr-python/releases.
  • Click "Draft a new release".
  • Choose a version number prefixed with a v (e.g. v0.0.0). For pre-releases, include the appropriate suffix (e.g. v0.0.0a1 or v0.0.0rc2).
  • Set the description of the release to: See release notes https://zarr.readthedocs.io/en/stable/release-notes.html#release-0-0-0, replacing the correct version numbers. For pre-release versions, the URL should omit the pre-release suffix, e.g. "a1" or "rc1".
  • Click on "Generate release notes" to auto-fill the description.
  • Make a release by clicking the 'Publish Release' button, this will automatically create a tag too.
• Verify that release workflows succeeded.
  • The latest version is correct on PyPI.
  • The stable version is correct on ReadTheDocs.

After release:

• Review and merge the pull request on the conda-forge zarr-feedstock that will be automatically generated.

---

• Party 🎉

[d-v-b]

@ianhi how is xarray looking?

[d-v-b]

@maxrjones is titiler.xarray ready for this?

[dcherian]

Xarray is good. We released last night.

[maxrjones]

@maxrjones is titiler.xarray ready for this?

I'll take a look now

[maxrjones]

https://github.com/developmentseed/titiler/actions/runs/16201456276/job/45741282163 @d-v-b all tests pass in titiler with Zarr's main branch

[d-v-b]

I'm going to move the release target date to Monday, July 14. Does this work for everyone?

[d-v-b]

reminder that we are going to try and close this out tomorrow. I would appreciate review of the following prs:

• remove usage of the _deprecate_positional_args decorator, and tests for its behavior #3225
• update release note for dtype refactor #3229
• update 2819 release note #3230

None of these are big. The first removes a decorator that complained when people used positional arguments on some functions, and the last two expand changlogs for past PRs.