Fix #2242 add checks for out indices with intermediate getter mode

Author: rwightman

timm/models/_features.py

@@ -17,7 +17,7 @@
 import torch.nn as nn
 from torch.utils.checkpoint import checkpoint
 
-from timm.layers import Format
+from timm.layers import Format, _assert
 
 
 __all__ = [
@@ -51,14 +51,15 @@ def feature_take_indices(
         indices = num_features  # all features if None
 
     if isinstance(indices, int):
-        assert indices >= 0
         # convert int -> last n indices
+        _assert(0 < indices <= num_features, f'last-n ({indices}) is out of range (1 to {num_features})')
         take_indices = [num_features - indices + i for i in range(indices)]
-    elif isinstance(indices, tuple):
-        # duplicating this is silly, but needed for torchscript type resolution of n
-        take_indices = [num_features + idx if idx < 0 else idx for idx in indices]
     else:
-        take_indices = [num_features + idx if idx < 0 else idx for idx in indices]
+        take_indices: List[int] = []
+        for i in indices:
+            idx = num_features + i if i < 0 else i
+            _assert(0 <= idx < num_features, f'feature index {idx} is out of range (0 to {num_features - 1})')
+            take_indices.append(idx)
 
     if not torch.jit.is_scripting() and as_set:
         return set(take_indices), max(take_indices)