refactor(BA-5983): make to_draft a method of ModelDefinitionInput

Address review feedback by moving the standalone
``to_model_definition_draft`` helper into ``ModelDefinitionInput.to_draft``
and update the test fixtures to use ``ModelDefinitionInput`` (matching
the field type) instead of ``ModelDefinitionDraft``.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: jopemachine

src/ai/backend/common/dto/manager/v2/deployment/request.py

@@ -176,13 +176,8 @@ class ModelDefinitionInput(BaseRequestModel):
 
     models: list[ModelConfigInput] | None = None
 
-
-def to_model_definition_draft(
-    input: ModelDefinitionInput | None,
-) -> ModelDefinitionDraft | None:
-    if input is None:
-        return None
-    return ModelDefinitionDraft.model_validate(input.model_dump())
+    def to_draft(self) -> ModelDefinitionDraft:
+        return ModelDefinitionDraft.model_validate(self.model_dump())
 
 
 class ClusterConfigInput(BaseRequestModel):

src/ai/backend/manager/api/adapters/deployment/adapter.py

@@ -62,7 +62,6 @@
     SyncReplicaInput,
     UpdateDeploymentInput,
     UpsertDeploymentPolicyInput,
-    to_model_definition_draft,
 )
 from ai.backend.common.dto.manager.v2.deployment.response import (
     AccessTokenNode,
@@ -506,7 +505,9 @@ async def create(
                     else None,
                 ),
                 mounts=mounts_creator,
-                model_definition=to_model_definition_draft(initial_revision.model_definition),
+                model_definition=initial_revision.model_definition.to_draft()
+                if initial_revision.model_definition is not None
+                else None,
                 revision_preset_id=initial_revision.revision_preset_id,
                 execution=ExecutionSpec(
                     runtime_variant_id=initial_revision.model_runtime_config.runtime_variant_id,
@@ -1111,7 +1112,9 @@ async def add_revision(
                 else None,
                 inference_runtime_config=input.model_runtime_config.inference_runtime_config,
             ),
-            model_definition=to_model_definition_draft(input.model_definition),
+            model_definition=input.model_definition.to_draft()
+            if input.model_definition is not None
+            else None,
             revision_preset_id=input.revision_preset_id,
         )
         action_result = await self._processors.deployment.add_model_revision.wait_for_complete(

tests/unit/common/dto/manager/v2/deployment/test_request.py

@@ -11,7 +11,6 @@
 from pydantic import ValidationError
 
 from ai.backend.common.api_handlers import SENTINEL, Sentinel
-from ai.backend.common.config import ModelDefinitionDraft
 from ai.backend.common.data.model_deployment.types import DeploymentStrategy
 from ai.backend.common.dto.manager.v2.deployment.request import (
     ActivateDeploymentInput,
@@ -25,6 +24,7 @@
     DeploymentStrategyInput,
     ExtraVFolderMountInput,
     ImageInput,
+    ModelDefinitionInput,
     ModelDeploymentMetadataInput,
     ModelDeploymentNetworkAccessInput,
     ModelMountConfigInput,
@@ -55,7 +55,7 @@ def _make_revision_input(**kwargs: object) -> RevisionInput:
         "runtime_variant_id": RuntimeVariantID(uuid.uuid4()),
         "model_vfolder_id": VFolderUUID(uuid.uuid4()),
         "model_definition_path": "/models/model.yaml",
-        "model_definition": ModelDefinitionDraft(),
+        "model_definition": ModelDefinitionInput(),
     }
     defaults.update(kwargs)
     return RevisionInput(**defaults)
@@ -82,7 +82,7 @@ def _make_create_revision_input_dto(**kwargs: object) -> CreateRevisionInputDTO:
             mount_destination="/models",
             definition_path="/models/model.yaml",
         ),
-        "model_definition": ModelDefinitionDraft(),
+        "model_definition": ModelDefinitionInput(),
     }
     defaults.update(kwargs)
     return CreateRevisionInputDTO(**defaults)
@@ -103,7 +103,7 @@ def test_valid_creation_with_required_fields(self) -> None:
             runtime_variant_id=runtime_variant_id,
             model_vfolder_id=model_id,
             model_definition_path="/models/def.yaml",
-            model_definition=ModelDefinitionDraft(),
+            model_definition=ModelDefinitionInput(),
         )
         assert rev.image_id == image_id
         assert rev.cluster_mode == ClusterMode.SINGLE_NODE