Bugfix: double remove of step_id in UI state

src/components/structs.py

@@ -83,6 +83,8 @@ class PipelineUIState(BaseModel):
 
     def remove_step(self, step_id: str) -> "PipelineUIState":
         """Remove a step from the pipeline."""
+        if step_id not in self.step_ids:
+            raise ValueError(f"Step {step_id} not found in pipeline. Step IDs: {self.step_ids}")
         self.step_ids.remove(step_id)
         self.steps.pop(step_id)
         return self.model_copy(update={"step_ids": self.step_ids, "steps": self.steps})
@@ -90,7 +92,7 @@ class PipelineUIState(BaseModel):
     def update_step(self, step_id: str, ui_state: ModelStepUIState) -> "PipelineUIState":
         """Update a step in the pipeline."""
         if step_id not in self.steps:
-            raise ValueError(f"Step {step_id} not found in pipeline")
+            raise ValueError(f"Step {step_id} not found in pipeline. Step IDs: {self.step_ids}")
         return self.model_copy(update={"steps": self.steps | {step_id: ui_state}})
 
 
@@ -125,7 +127,7 @@ class PipelineState(BaseModel):
         return self.model_copy(update={"workflow": workflow, "ui_state": self.ui_state})
 
     def remove_step(self, position: int) -> "PipelineState":
-        step_id = self.ui_state.step_ids.pop(position)
+        step_id = self.ui_state.step_ids[position]
 
         workflow = self.workflow.remove_step(step_id)
         ui_state = self.ui_state.remove_step(step_id)