error for old polars version

Author: TrevorBergeron

bigframes/_config/bigquery_options.py

@@ -22,6 +22,7 @@
 import google.auth.credentials
 import requests.adapters
 
+import bigframes._importing
 import bigframes.enums
 import bigframes.exceptions as bfe
 
@@ -114,6 +115,8 @@ def __init__(
             client_endpoints_override = {}
 
         self._client_endpoints_override = client_endpoints_override
+        if enable_polars_execution:
+            bigframes._importing.import_polars()
         self._enable_polars_execution = enable_polars_execution
 
     @property
@@ -439,4 +442,5 @@ def enable_polars_execution(self, value: bool):
                 "Polars execution is an experimental feature, and may not be stable. Must have polars installed."
             )
             warnings.warn(msg, category=bfe.PreviewWarning)
+            bigframes._importing.import_polars()
         self._enable_polars_execution = value

bigframes/_importing.py

@@ -0,0 +1,30 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import importlib
+from types import ModuleType
+
+from packaging import version
+
+# Keep this in sync with setup.py
+POLARS_MIN_VERSION = version.Version("1.7.0")
+
+
+def import_polars() -> ModuleType:
+    polars_module = importlib.import_module("polars")
+    imported_version = version.Version(polars_module.build_info()["version"])
+    if imported_version < POLARS_MIN_VERSION:
+        raise ImportError(
+            f"Imported polars version: {imported_version} is below the minimum version: {POLARS_MIN_VERSION}"
+        )
+    return polars_module

noxfile.py

@@ -107,7 +107,7 @@
 SYSTEM_TEST_EXTRAS: List[str] = []
 SYSTEM_TEST_EXTRAS_BY_PYTHON: Dict[str, List[str]] = {
     "3.9": ["tests"],
-    "3.10": ["tests"],
+    "3.10": ["tests", "polars"],
     "3.12": ["tests", "scikit-learn", "polars"],
     "3.13": ["tests", "polars"],
 }

testing/constraints-3.10.txt

@@ -15,3 +15,4 @@ matplotlib==3.7.1
 psutil==5.9.5
 seaborn==0.13.1
 traitlets==5.7.1
+polars==1.7.0