deps: Rename 'extra' dependency group to 'sklearn' (#3696)

* deps: Rename 'extra' to 'sklearn'

* rm in line comment

---------

Co-authored-by: Dan Redding <125183946+dangotbanned@users.noreply.github.com>

Author: FBruzzesi

.github/workflows/pytest-pyspark.yml

@@ -93,7 +93,7 @@ jobs:
 
       - name: install-reqs
         # temporary pin to get CI green
-        run: uv pip install -e ".[pandas]" --group core-tests --group extra "pyarrow<22.0"
+        run: uv pip install -e ".[pandas]" --group core-tests --group sklearn "pyarrow<22.0"
       - name: install pyspark
         run: uv pip install -e . "pyspark[connect]==${SPARK_VERSION}" "setuptools<78"
       - name: show-deps

.github/workflows/pytest.yml

@@ -53,7 +53,7 @@ jobs:
       # we are not testing pyspark, modin, or dask on Windows here because nobody got time for that
       - name: Run pytest
         shell: bash
-        run: make run-ci DEPS="--group core-tests --group extra --group plugins --extra pandas" CMD="pytest tests --cov=src --cov=tests --runslow --cov-fail-under=95 --durations=30 --constructors=pandas,pandas[nullable],pandas[pyarrow],pyarrow,polars[eager],polars[lazy],duckdb,sqlframe"
+        run: make run-ci DEPS="--group core-tests --group sklearn --group plugins --extra pandas" CMD="pytest tests --cov=src --cov=tests --runslow --cov-fail-under=95 --durations=30 --constructors=pandas,pandas[nullable],pandas[pyarrow],pyarrow,polars[eager],polars[lazy],duckdb,sqlframe"
 
   pytest-full-coverage:
     if: github.head_ref != 'bump-version'
@@ -77,11 +77,11 @@ jobs:
           cache-suffix: pytest-full-coverage-${{ matrix.python-version }}
           cache-dependency-glob: "pyproject.toml"
       - name: Run pytest
-        run: make run-ci DEPS="--extra pandas --extra dask --group core-tests --group extra --group plugins" CMD="pytest tests --cov=src --cov=tests --cov-fail-under=100 --runslow --durations=30 --constructors=pandas,pandas[nullable],pandas[pyarrow],pyarrow,polars[eager],polars[lazy],dask,duckdb,sqlframe"
+        run: make run-ci DEPS="--extra pandas --extra dask --group core-tests --group sklearn --group plugins" CMD="pytest tests --cov=src --cov=tests --cov-fail-under=100 --runslow --durations=30 --constructors=pandas,pandas[nullable],pandas[pyarrow],pyarrow,polars[eager],polars[lazy],dask,duckdb,sqlframe"
       - name: Run doctests
         # reprs differ between versions, so we only run doctests on the latest Python
         if: matrix.python-version == '3.13'
-        run: make run-ci DEPS="--extra pandas --extra dask --group core-tests --group extra" CMD="pytest src --doctest-modules"
+        run: make run-ci DEPS="--extra pandas --extra dask --group core-tests --group sklearn" CMD="pytest src --doctest-modules"
 
   # Test against smaller dependency set, used e.g. on Gentoo.
   pytest-narrower-dependencies:

pyproject.toml

@@ -86,7 +86,7 @@ tests = [
 # CI jobs that measure `tests/` coverage add `--group plugins` explicitly.
 # See https://github.com/narwhals-dev/narwhals/pull/3664 and https://github.com/narwhals-dev/narwhals/pull/3665
 
-extra = [  # heavier dependencies we don't necessarily need in every testing job
+sklearn = [
   "scikit-learn",
 ]
 typing = [  # keep some of these pinned and bump periodically so there's fewer surprises for contributors