It's **not supported** by Pydantic to have a model of Pydantic v2 with its own fields defined as Pydantic v1 models or vice versa.

```mermaid
graph TB
    subgraph "❌ Not Supported"
        direction TB
        subgraph V2["Pydantic v2 Model"]
            V1Field["Pydantic v1 Model"]
        end
        subgraph V1["Pydantic v1 Model"]
            V2Field["Pydantic v2 Model"]
        end
    end

import model.CIBuildModel
import model.Stage

fun asDocsTestId(
    model: CIBuildModel,
    os: Os,
): String = "${model.projectId}_DocsTest_${os.asName()}"

class DocsTestProject(
    model: CIBuildModel,
    stage: Stage,
    val os: Os,
    testJava: JvmCategory,
    testTypes: List<DocsTestType>,
) : Project({
        id(asDocsTestId(model, os))

import common.buildScanTagParam
import common.getBuildScanCustomValueParam
import common.setArtifactRules
import model.CIBuildModel
import model.Stage

class BuildDistributions(
    model: CIBuildModel,
    stage: Stage,
) : OsAwareBaseGradleBuildType(os = LINUX, stage = stage, init = {
        id("${model.projectId}_BuildDistributions")
        name = "Build Distributions"

import org.apache.maven.model.InputLocation;
import org.apache.maven.model.Model;
import org.apache.maven.model.building.ModelBuildingRequest;
import org.apache.maven.model.building.ModelProblem.Severity;
import org.apache.maven.model.building.ModelProblem.Version;
import org.apache.maven.model.building.ModelProblemCollector;
import org.apache.maven.model.building.ModelProblemCollectorRequest;

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.model.building;

/**
 * Caches auxiliary data used during model building like already processed raw/effective models. The data in the cache
 * is meant for exclusive consumption by the model builder and is opaque to the cache implementation. The cache key is

	// Clear
	DB.Model(&users).Association("Company").Clear()
	AssertAssociationCount(t, users, "Company", 0, "After Clear")

	DB.Model(&users).Association("Manager").Clear()
	AssertAssociationCount(t, users, "Manager", 0, "After Clear")

	// shared company
	company := Company{Name: "shared"}
	if err := DB.Model(&users[0]).Association("Company").Append(&company); err != nil {

          <basedir>${project.basedir}/../../api/maven-api-toolchain</basedir>
          <velocityBasedir>${project.basedir}/../../src/mdo</velocityBasedir>
          <models>
            <model>src/main/mdo/toolchains.mdo</model>
          </models>
        </configuration>
        <executions>
          <execution>
            <id>velocity</id>
            <goals>
              <goal>velocity</goal>
            </goals>

 * under the License.
 */
package org.apache.maven.model.plugin;

import javax.inject.Named;
import javax.inject.Singleton;

import java.util.List;

import org.apache.maven.model.Build;
import org.apache.maven.model.Model;
import org.apache.maven.model.Plugin;
import org.apache.maven.model.PluginExecution;
import org.apache.maven.model.PluginManagement;
import org.apache.maven.model.building.ModelBuildingRequest;

 * under the License.
 */
package org.apache.maven.model.profile.activation;

import javax.inject.Named;
import javax.inject.Singleton;

import org.apache.maven.model.Activation;
import org.apache.maven.model.ActivationProperty;
import org.apache.maven.model.Profile;
import org.apache.maven.model.building.ModelProblem.Severity;
import org.apache.maven.model.building.ModelProblem.Version;

    return {"p": p}


class CookieModelOptionalStr(BaseModel):
    p: Optional[str] = None


@app.get("/model-optional-str")
async def read_model_optional_str(p: Annotated[CookieModelOptionalStr, Cookie()]):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/optional-str", "/model-optional-str"],
)
def test_optional_str_schema(path: str):
    assert app.openapi()["paths"][path]["get"]["parameters"] == [