Replace Assert statement with ValueError message.

test/test_backbone_utils.py

@@ -7,9 +7,8 @@
 from common_utils import set_rng_seed
 from torchvision import models
 from torchvision.models._utils import IntermediateLayerGetter
-from torchvision.models.detection.backbone_utils import resnet_fpn_backbone
-from torchvision.models.feature_extraction import create_feature_extractor
-from torchvision.models.feature_extraction import get_graph_node_names
+from torchvision.models.detection.backbone_utils import mobilenet_backbone, resnet_fpn_backbone
+from torchvision.models.feature_extraction import create_feature_extractor, get_graph_node_names
 
 
 def get_available_models():
@@ -23,6 +22,23 @@ def test_resnet_fpn_backbone(backbone_name):
     y = resnet_fpn_backbone(backbone_name=backbone_name, pretrained=False)(x)
     assert list(y.keys()) == ["0", "1", "2", "3", "pool"]
 
+    with pytest.raises(ValueError, " trainable_layers  expected to be in [0,5], got 6"):
+        resnet_fpn_backbone(backbone_name=backbone_name, pretrained=False, trainable_layers=6)
+    with pytest.raises(ValueError, "Each returned layer must be in the range [1,4]. Got 0"):
+        resnet_fpn_backbone(backbone_name, False, returned_layers=[0, 1, 2, 3])
+    with pytest.raises(ValueError, "Each returned layer must be in the range [1,4]. Got 5"):
+        resnet_fpn_backbone(backbone_name, False, returned_layers=[2, 3, 4, 5])
+
+
+@pytest.mark.parametrize("backbone_name", ("mobilenet_v2", "mobilenet_v3_large", "mobilenet_v3_small"))
+def test_mobilenet_backbone(backbone_name):
+    with pytest.raises(ValueError):
+        mobilenet_backbone(backbone_name=backbone_name, pretrained=False, fpn=False, trainable_layers=-1)
+    with pytest.raises(ValueError):
+        mobilenet_backbone(backbone_name, False, fpn=True, returned_layers=[-1, 0, 1, 2])
+    with pytest.raises(ValueError):
+        mobilenet_backbone(backbone_name, False, fpn=True, returned_layers=[3, 4, 5, 6])
+
 
 # Needed by TestFxFeatureExtraction.test_leaf_module_and_function
 def leaf_function(x):

test/test_models_detection_utils.py

@@ -3,8 +3,7 @@
 import pytest
 import torch
 from common_utils import assert_equal
-from torchvision.models.detection import _utils
-from torchvision.models.detection import backbone_utils
+from torchvision.models.detection import _utils, backbone_utils
 from torchvision.models.detection.transform import GeneralizedRCNNTransform
 
 
@@ -54,7 +53,7 @@ def test_validate_resnet_inputs_detection(self):
         )
         assert ret == 3
         # can't go beyond 5
-        with pytest.raises(AssertionError):
+        with pytest.raises(ValueError, "trainable_backbone_layers expected to be in between [0,5], got 6 "):
             ret = backbone_utils._validate_trainable_layers(
                 pretrained=True, trainable_backbone_layers=6, max_value=5, default_value=3
             )

torchvision/models/detection/backbone_utils.py

@@ -111,7 +111,8 @@ def _resnet_fpn_extractor(
 ) -> BackboneWithFPN:
 
     # select layers that wont be frozen
-    assert 0 <= trainable_layers <= 5
+    if trainable_layers < 0 or trainable_layers > 5:
+        raise ValueError(f" trainable_layers  expected to be in [0,5], got {trainable_layers}")
     layers_to_train = ["layer4", "layer3", "layer2", "layer1", "conv1"][:trainable_layers]
     if trainable_layers == 5:
         layers_to_train.append("bn1")
@@ -124,7 +125,8 @@ def _resnet_fpn_extractor(
 
     if returned_layers is None:
         returned_layers = [1, 2, 3, 4]
-    assert min(returned_layers) > 0 and max(returned_layers) < 5
+    if min(returned_layers) <= 0 or max(returned_layers) >= 5:
+        raise ValueError(f"Each returned layer must be in the range [1,4]. Got {returned_layers}")
     return_layers = {f"layer{k}": str(v) for v, k in enumerate(returned_layers)}
 
     in_channels_stage2 = backbone.inplanes // 8
@@ -152,7 +154,10 @@ def _validate_trainable_layers(
     # by default freeze first blocks
     if trainable_backbone_layers is None:
         trainable_backbone_layers = default_value
-    assert 0 <= trainable_backbone_layers <= max_value
+    if trainable_backbone_layers < 0 or trainable_backbone_layers > max_value:
+        raise ValueError(
+            f"trainable_backbone_layers expected to be in between [0,{max_value}], got {trainable_backbone_layers} "
+        )
     return trainable_backbone_layers
 
 
@@ -172,7 +177,7 @@ def mobilenet_backbone(
 def _mobilenet_extractor(
     backbone: Union[mobilenet.MobileNetV2, mobilenet.MobileNetV3],
     fpn: bool,
-    trainable_layers,
+    trainable_layers: int,
     returned_layers: Optional[List[int]] = None,
     extra_blocks: Optional[ExtraFPNBlock] = None,
 ) -> nn.Module:
@@ -183,7 +188,8 @@ def _mobilenet_extractor(
     num_stages = len(stage_indices)
 
     # find the index of the layer from which we wont freeze
-    assert 0 <= trainable_layers <= num_stages
+    if trainable_layers < 0 or trainable_layers > num_stages:
+        raise ValueError(f"trainable_layers expected to be in between [0,{num_stages}], got {trainable_layers} ")
     freeze_before = len(backbone) if trainable_layers == 0 else stage_indices[num_stages - trainable_layers]
 
     for b in backbone[:freeze_before]:
@@ -197,7 +203,10 @@ def _mobilenet_extractor(
 
         if returned_layers is None:
             returned_layers = [num_stages - 2, num_stages - 1]
-        assert min(returned_layers) >= 0 and max(returned_layers) < num_stages
+        if min(returned_layers) <= 0 or max(returned_layers) >= num_stages:
+            raise ValueError(
+                f" returned_layers object should contain integers between [1,{num_stages - 1}], got {returned_layers} "
+            )
         return_layers = {f"{stage_indices[k]}": str(v) for v, k in enumerate(returned_layers)}
 
         in_channels_list = [backbone[stage_indices[i]].out_channels for i in returned_layers]