Skip pydantic.v1 import on Python 3.14+ to avoid UserWarning (#4283)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: zshuzh

RELEASE.md

@@ -0,0 +1,7 @@
+Release type: patch
+
+Fix compatibility with Python 3.14 when using the Pydantic integration with Pydantic V2. Previously, importing `strawberry.experimental.pydantic` on Python 3.14 would trigger:
+
+    UserWarning: Core Pydantic V1 functionality isn't compatible with Python 3.14 or greater.
+
+This is now fixed by avoiding `pydantic.v1` imports on Python 3.14+.

strawberry/experimental/pydantic/_compat.py

@@ -1,4 +1,5 @@
 import dataclasses
+import sys
 from collections.abc import Callable
 from dataclasses import dataclass
 from decimal import Decimal
@@ -22,6 +23,9 @@
 def _get_base_model_types() -> tuple[type[Any], ...]:
     model_types: list[type[Any]] = [BaseModel]
 
+    if sys.version_info >= (3, 14):
+        return tuple(model_types)
+
     try:
         from pydantic.v1 import BaseModel as BaseModelV1
     except ImportError:

tests/experimental/pydantic/schema/test_1_and_2.py

@@ -1,5 +1,7 @@
+import importlib
 import sys
 import textwrap
+import warnings
 
 import pytest
 
@@ -132,3 +134,19 @@ class Query:
     """
 
     assert str(schema) == textwrap.dedent(expected_schema).strip()
+
+
+@pytest.mark.skipif(
+    sys.version_info < (3, 14),
+    reason="This test is only relevant on Python 3.14+",
+)
+@needs_pydantic_v2
+def test_no_pydantic_v1_warning_on_python_314():
+    import strawberry.experimental.pydantic._compat as compat_module
+
+    with warnings.catch_warnings(record=True) as caught:
+        warnings.simplefilter("always")
+        importlib.reload(compat_module)
+
+    pydantic_v1_warnings = [w for w in caught if "Pydantic V1" in str(w.message)]
+    assert pydantic_v1_warnings == []