pixi solve strategy lowest and highest

[LuukBlom]

Explanation

Add lowest dependency solving to the test matrix.
Only use pypi, and no conda packages anymore. This works because we removed GDAL and instead use rio-vrt as dependency.

General Checklist

• Updated tests or added new tests
• Branch is up to date with main
• Tests & pre-commit hooks pass
• Updated documentation
• Updated changelog.rst

Data/Catalog checklist

• data/catalogs/predefined_catalogs.yml has not been modified.
• None of the old data_catalog.yml files have been changed
• data/changelog.rst has been updated
• new file uses LF line endings (done automatically if you used update_versions.py)
• New file has been tested locally
• Tests have been added using the new file in the test suite

Additional Notes (optional)

Add any additional notes or information that may be helpful.

[Copilot]

Pull request overview

This PR updates HydroMT’s dependency management and CI to support “lowest-direct” dependency solving via pixi, while removing the explicit GDAL Python bindings requirement by switching VRT tile caching to rio-vrt. It also adjusts tests and docs to match the new dependency approach (PyPI-only focus) and updated tooling.

Changes:

• Add a new pixi “lowest-deps” solve strategy and run it in the GitHub Actions test matrix.
• Remove HAS_GDAL compatibility plumbing and switch VRT caching from osgeo.gdal.BuildVRT to rio_vrt.build_vrt, updating tests accordingly.
• Refresh CI/docs tooling (pixi version bump, pandoc installation guidance and workflow step) and modernize some typing / test assertions.

Reviewed changes

Copilot reviewed 23 out of 24 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tests/test_plugins.py	Adjusts entry point mocking to only intercept the components entry point group.
tests/data_catalog/test_data_catalog.py	Removes GDAL-based skip conditions from integration tests now that GDAL bindings are no longer required.
tests/data_catalog/drivers/raster/test_rasterio_driver.py	Removes GDAL skip/import to run raster caching tests unconditionally.
tests/data_catalog/drivers/raster/test_raster_xarray_driver.py	Makes coord assertions order-independent.
tests/data_catalog/drivers/geodataset/test_xarray_driver.py	Makes coord assertions order-independent.
tests/data_catalog/drivers/dataset/test_dataset_xarray_driver.py	Makes coord assertions order-independent.
tests/conftest.py	Moves global test configuration into session autouse fixtures and guards xarray option by version.
tests/_utils/test_caching.py	Removes GDAL-dependent skips and a GDAL-missing error-path test.
pyproject.toml	Updates dependency lower bounds, adds rio-vrt, adds “lowest-deps” pixi feature, updates pixi environments/CI targets.
hydromt/data_catalog/uri_resolvers/uri_resolver.py	Modernizes type hints to `X
hydromt/data_catalog/sources/data_source.py	Modernizes typing (dict[str, …], list[str]) in a few methods.
hydromt/data_catalog/data_catalog.py	Removes outdated docstring note about requiring GDAL Python bindings for caching.
hydromt/_utils/caching.py	Replaces GDAL BuildVRT usage with rio_vrt.build_vrt and removes GDAL import/guard.
hydromt/_compat.py	Removes HAS_GDAL detection flag.
docs/dev/plugin_dev/example_test.yml	Bumps pixi version used in the example workflow.
docs/dev/core_dev/dev_install.rst	Documents pandoc as an external (pixi-global) requirement for docs builds.
.github/workflows/tests.yml	Adds “low” dependency environment to test matrix and bumps pixi version.
.github/workflows/sonar.yml	Bumps pixi version.
.github/workflows/pixi_auto_update.yml	Bumps pixi version.
.github/workflows/downstream-plugins.yml	Bumps pixi version.
.github/workflows/docs.yml	Bumps pixi version and installs pandoc via pixi global install.
.github/workflows/create-release.yml	Bumps pixi version.
.github/workflows/check-data-catalogs.yml	Bumps pixi version.

Comments suppressed due to low confidence (1)

hydromt/data_catalog/sources/data_source.py:174

• _get_relative_uri is annotated to always return Path, but it can return None when handle_nodata is set to ignore (see the return None branch). Update the return type to Path | None to reflect actual behavior and avoid type/IDE confusion.

        return res

    def _get_relative_uri(self, handle_nodata: NoDataStrategy, **query_kwargs) -> Path:
        uri = PurePath(self.uri)
        if "{" in self.uri:
            # first resolve any placeholders
            uris: list[str] = self.uri_resolver.resolve(
                uri=self.full_uri,
                handle_nodata=handle_nodata,
                **query_kwargs,
            )
            if not uris:
                return None  # handle_nodata == ignore
            # if multiple_uris, use the first one:

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[LuukBlom]

rio-vrt has only 1 maintainer, and the last commit and release was done 2 years ago.

I had to introduce a workaround for our tests since rio-vrt.build_vrt has a bug, resulting in TypeErrors when the tiles list has only 1 element.
I dont think this will happen often outside of tests, but its a cryptic error that we should handle imo.

There are 2 things we an easily do:

1. have this workaround solution that deduplicates the xml (this passes our tests)

    # Pass duplicated list, then strip the duplicate source from the written XML.
    duplicated = False
    if len(new) == 1:
        new = new + new
        duplicated = True

    build_vrt(vrt_destination_path, new)

    # de-duplicate
    if duplicated:
        tree = ET.parse(vrt_destination_path)
        for band in tree.getroot().findall("VRTRasterBand"):
            source_els = [s for s in band if s.tag.endswith("Source")]
            if len(source_els) > 1:
                band.remove(source_els[-1])
        tree.write(vrt_destination_path, xml_declaration=True, encoding="UTF-8")

OR

2. raise an informative error when there is only 0 or 1 files.

    if len(new) <= 1:
        raise ValueError("Need at least 2 files when creating a vrt")
    build_vrt(vrt_destination_path, new)

1 is a bit ugly, but 2 breaks usage when users query a small bbox/region that only intersects 1 tile.

Any opinions @deltamarnix ?

[LuukBlom]

I created an issue for the bug in the rio-vrt repo: 12rambau/rio-vrt#26

It seems to not be maintained actively anymore, so good to manage expectations.