update `get_parameter_dtype` (#10342)

add:
q

src/diffusers/models/modeling_utils.py

@@ -99,21 +99,39 @@ def get_parameter_device(parameter: torch.nn.Module) -> torch.device:
 
 
 def get_parameter_dtype(parameter: torch.nn.Module) -> torch.dtype:
-    try:
-        return next(parameter.parameters()).dtype
-    except StopIteration:
-        try:
-            return next(parameter.buffers()).dtype
-        except StopIteration:
-            # For torch.nn.DataParallel compatibility in PyTorch 1.5
-
-            def find_tensor_attributes(module: torch.nn.Module) -> List[Tuple[str, Tensor]]:
-                tuples = [(k, v) for k, v in module.__dict__.items() if torch.is_tensor(v)]
-                return tuples
-
-            gen = parameter._named_members(get_members_fn=find_tensor_attributes)
-            first_tuple = next(gen)
-            return first_tuple[1].dtype
+    """
+    Returns the first found floating dtype in parameters if there is one, otherwise returns the last dtype it found.
+    """
+    last_dtype = None
+    for param in parameter.parameters():
+        last_dtype = param.dtype
+        if param.is_floating_point():
+            return param.dtype
+
+    for buffer in parameter.buffers():
+        last_dtype = buffer.dtype
+        if buffer.is_floating_point():
+            return buffer.dtype
+
+    if last_dtype is not None:
+        # if no floating dtype was found return whatever the first dtype is
+        return last_dtype
+
+    # For nn.DataParallel compatibility in PyTorch > 1.5
+    def find_tensor_attributes(module: nn.Module) -> List[Tuple[str, Tensor]]:
+        tuples = [(k, v) for k, v in module.__dict__.items() if torch.is_tensor(v)]
+        return tuples
+
+    gen = parameter._named_members(get_members_fn=find_tensor_attributes)
+    last_tuple = None
+    for tuple in gen:
+        last_tuple = tuple
+        if tuple[1].is_floating_point():
+            return tuple[1].dtype
+
+    if last_tuple is not None:
+        # fallback to the last dtype
+        return last_tuple[1].dtype
 
 
 class ModelMixin(torch.nn.Module, PushToHubMixin):