Fix settings of cache provider by environment variable

modelkit/core/settings.py

@@ -95,16 +95,15 @@ class NativeCacheSettings(CacheSettings):
 
 def cache_settings():
     s = CacheSettings()
-    if s.cache_provider is None:
+
+    if s.cache_provider == "none":
         return None
-    try:
+    elif s.cache_provider == "redis":
         return RedisSettings()
-    except pydantic.ValidationError:
-        pass
-    try:
+    elif s.cache_provider == "native":
         return NativeCacheSettings()
-    except pydantic.ValidationError:
-        pass
+    else:
+        return None
 
 
 def _get_library_settings_cache_provider(v: Optional[str]) -> str:
@@ -134,8 +133,5 @@ class LibrarySettings(ModelkitSettings):
             Annotated[None, pydantic.Tag("none")],
         ],
         pydantic.Discriminator(_get_library_settings_cache_provider),
-    ] = pydantic.Field(
-        default_factory=cache_settings,
-        union_mode="left_to_right",
-    )
+    ] = pydantic.Field(default_factory=cache_settings)
     model_config = pydantic.ConfigDict(extra="allow")

tests/test_settings.py

@@ -62,18 +62,15 @@ def test_cache_provider_settings(monkeypatch):
     assert lib_settings.cache.cache_provider == "redis"
 
     monkeypatch.setenv("MODELKIT_CACHE_PROVIDER", "native")
-    with pytest.raises(pydantic.ValidationError):  # FIXME: shouldn't raise
-        lib_settings = LibrarySettings()
-        assert isinstance(lib_settings.cache, NativeCacheSettings)
-        assert lib_settings.cache.cache_provider == "native"
+    lib_settings = LibrarySettings()
+    assert isinstance(lib_settings.cache, NativeCacheSettings)
+    assert lib_settings.cache.cache_provider == "native"
 
     monkeypatch.setenv("MODELKIT_CACHE_PROVIDER", "none")
-    with pytest.raises(pydantic.ValidationError):  # FIXME: shouldn't raise
-        assert LibrarySettings().cache is None
+    assert LibrarySettings().cache is None
 
     monkeypatch.setenv("MODELKIT_CACHE_PROVIDER", "not supported")
-    with pytest.raises(pydantic.ValidationError):  # FIXME: shouldn't raise
-        assert LibrarySettings().cache is None
+    assert LibrarySettings().cache is None
 
     monkeypatch.delenv("MODELKIT_CACHE_PROVIDER")
     assert LibrarySettings().cache is None