`torch.jit.trace()` fix (#9363)

.github/workflows/ci-testing.yml

@@ -119,9 +119,12 @@ jobs:
           python export.py --weights $m.pt --img 64 --include torchscript  # export
           python - <<EOF
           import torch
+          im = torch.zeros([1, 3, 64, 64])
           for path in '$m', '$b':
               model = torch.hub.load('.', 'custom', path=path, source='local')
               print(model('data/images/bus.jpg'))
+              model(im)  # warmup, build grids for trace
+              torch.jit.trace(model, [im])
           EOF
       - name: Test classification
         shell: bash  # for Windows compatibility

models/common.py

@@ -600,6 +600,7 @@ class AutoShape(nn.Module):
         if self.pt:
             m = self.model.model.model[-1] if self.dmb else self.model.model[-1]  # Detect()
             m.inplace = False  # Detect.inplace=False for safe multithread inference
+            m.export = True  # do not output loss values
 
     def _apply(self, fn):
         # Apply to(), cpu(), cuda(), half() to model tensors that are not parameters or registered buffers