fix(python): Respect dtype and strict in pl.Series's constructor for pyarrow arrays, numpy arrays, and pyarrow-backed pandas

py-polars/polars/_utils/construction/series.py

@@ -422,9 +422,10 @@ def pandas_to_pyseries(
             "(e.g. 'int64', 'bool', 'float32' - not 'Int64')"
         )
         raise ImportError(msg)
-    return arrow_to_pyseries(
+    s = arrow_to_pyseries(
         name, plc.pandas_series_to_arrow(values, nan_to_null=nan_to_null)
     )
+    return s if dtype is None else s.cast(dtype, strict=False)
 
 
 def arrow_to_pyseries(name: str, values: pa.Array, *, rechunk: bool = True) -> PySeries:

py-polars/tests/unit/series/test_series.py

@@ -2342,3 +2342,5 @@ def test_search_sorted(
 def test_series_from_pandas_with_dtype() -> None:
     s = pl.Series("foo", pd.Series([1, 2, 3]), pl.Float32)
     assert_series_equal(s, pl.Series("foo", [1, 2, 3], dtype=pl.Float32))
+    s = pl.Series("foo", pd.Series([1, 2, 3], dtype="Int64"), pl.Float32)
+    assert_series_equal(s, pl.Series("foo", [1, 2, 3], dtype=pl.Float32))