Use pydantic.RootModel for PipelineComponents

Fixes #381

kpops/pipeline_generator/pipeline.py

@@ -7,7 +7,7 @@
 from typing import TYPE_CHECKING
 
 import yaml
-from pydantic import BaseModel, SerializeAsAny
+from pydantic import RootModel, SerializeAsAny
 from rich.console import Console
 from rich.syntax import Syntax
 
@@ -35,37 +35,37 @@ class ValidationError(Exception):
     pass
 
 
-class PipelineComponents(BaseModel):
+class PipelineComponents(RootModel):
     """Stores the pipeline components."""
 
-    components: list[SerializeAsAny[PipelineComponent]] = []
+    root: list[SerializeAsAny[PipelineComponent]] = []
 
     @property
     def last(self) -> PipelineComponent:
-        return self.components[-1]
+        return self.root[-1]
 
     def find(self, component_name: str) -> PipelineComponent:
-        for component in self.components:
+        for component in self.root:
             if component_name == component.name:
                 return component
         msg = f"Component {component_name} not found"
         raise ValueError(msg)
 
     def add(self, component: PipelineComponent) -> None:
         self._populate_component_name(component)
-        self.components.append(component)
+        self.root.append(component)
 
     def __bool__(self) -> bool:
-        return bool(self.components)
+        return bool(self.root)
 
     def __iter__(self) -> Iterator[PipelineComponent]:
-        return iter(self.components)
+        return iter(self.root)
 
     def __len__(self) -> int:
-        return len(self.components)
+        return len(self.root)
 
     def validate_unique_names(self) -> None:
-        step_names = [component.full_name for component in self.components]
+        step_names = [component.full_name for component in self.root]
         duplicates = [name for name, count in Counter(step_names).items() if count > 1]
         if duplicates:
             msg = f"step names should be unique. duplicate step names: {', '.join(duplicates)}"