make inputs truly immutable, remove the output logic in sequential pipeline, and update so that intermediates_outputs are only new variables

Author: yiyixuxu

src/diffusers/modular_pipelines/modular_pipeline.py

@@ -17,6 +17,7 @@
 from collections import OrderedDict
 from dataclasses import dataclass, field
 from typing import Any, Dict, List, Tuple, Union, Optional, Type
+from copy import deepcopy
 
 
 import torch
@@ -109,7 +110,9 @@ def add_intermediate(self, key: str, value: Any, kwargs_type: str = None):
                 self.intermediate_kwargs[kwargs_type].append(key)
 
     def get_input(self, key: str, default: Any = None) -> Any:
-        return self.inputs.get(key, default)
+        value = self.inputs.get(key, default)
+        if value is not None:
+            return deepcopy(value)
 
     def get_inputs(self, keys: List[str], default: Any = None) -> Dict[str, Any]:
         return {key: self.inputs.get(key, default) for key in keys}
@@ -483,6 +486,7 @@ def doc(self):
         )
 
 
+    # YiYi TODO: input and inteermediate inputs with same name? should warn?
     def get_block_state(self, state: PipelineState) -> dict:
         """Get all inputs and intermediates in one dictionary"""
         data = {}
@@ -1032,14 +1036,21 @@ def get_intermediates_inputs(self):
 
     @property
     def intermediates_outputs(self) -> List[str]:
-        named_outputs = [(name, block.intermediates_outputs) for name, block in self.blocks.items()]
+        named_outputs = []
+        for name, block in self.blocks.items():
+            inp_names = set([inp.name for inp in block.intermediates_inputs])
+            # so we only need to list new variables as intermediates_outputs, but if user wants to list these they modified it's still fine (a.k.a we don't enforce)
+            # filter out them here so they do not end up as intermediates_outputs
+            if name not in inp_names:
+                named_outputs.append((name, block.intermediates_outputs))
         combined_outputs = combine_outputs(*named_outputs)
         return combined_outputs
 
+    # YiYi TODO: I think we can remove the outputs property
     @property
     def outputs(self) -> List[str]:
-        return next(reversed(self.blocks.values())).intermediates_outputs
-    
+        # return next(reversed(self.blocks.values())).intermediates_outputs
+        return self.intermediates_outputs
     @torch.no_grad()
     def __call__(self, pipeline, state: PipelineState) -> PipelineState:
         for block_name, block in self.blocks.items():