fix: import crash on narwhals 1.x; bump to 0.3.5

.github/workflows/ci.yml

@@ -20,6 +20,18 @@ jobs:
       - name: Run tests with coverage
         run: uv run --all-extras pytest --cov=centimators --cov-report=term
 
+  # The lockfile tracks latest narwhals; the declared floor is much older and
+  # narwhals 1.x exposes typing aliases as runtime strings, which annotations
+  # can trip on at import time. Smoke-test imports at the floor so a green
+  # lockfile can't hide a broken install for downstream pins.
+  test-narwhals-floor:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: astral-sh/setup-uv@v4
+      - name: Import smoke test on minimum supported narwhals
+        run: uv run --all-extras --with "narwhals==1.39.0" pytest tests/test_imports.py
+
   lint:
     runs-on: ubuntu-latest
     steps:

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "centimators"
-version = "0.3.4"
+version = "0.3.5"
 description = "essential data transformers and model estimators for ML and data science competitions"
 readme = "README.md"
 authors = [

src/centimators/feature_transformers/neutralization.py

@@ -1,5 +1,7 @@
 """Neutralization transformers for reducing feature exposure."""
 
+from __future__ import annotations
+
 import warnings
 
 import narwhals as nw

src/centimators/feature_transformers/penalization.py

@@ -1,5 +1,7 @@
 """Feature penalization transformers using iterative optimization (requires JAX)."""
 
+from __future__ import annotations
+
 import warnings
 
 import narwhals as nw

tests/test_imports.py

@@ -0,0 +1,29 @@
+"""Import smoke tests.
+
+Every module must import cleanly (or fail only with ImportError for optional
+dependencies) on every supported narwhals version. Regression guard for the
+narwhals 1.x incident where ``IntoSeries | None`` in a runtime-evaluated
+signature raised TypeError at import time: narwhals 1.x exposes
+``narwhals.typing`` aliases as plain strings at runtime, so any module using
+them in annotations must carry ``from __future__ import annotations``.
+"""
+
+import importlib
+import pkgutil
+
+import centimators
+
+
+def test_top_level_import():
+    assert hasattr(centimators, "RankTransformer")
+
+
+def test_all_modules_import():
+    prefix = centimators.__name__ + "."
+    for mod_info in pkgutil.walk_packages(centimators.__path__, prefix):
+        try:
+            importlib.import_module(mod_info.name)
+        except ImportError:
+            # Optional dependencies (jax, dspy, keras, umap) may be absent;
+            # anything else (e.g. TypeError from annotation evaluation) fails.
+            continue