Add typing annotations to detection/generalized_rcnn (#4631)

* Update typing

* Fix bug

* Unblock mypy

* Ignore small error
Co-authored-by: Vasilis Vryniotis <datumbox@users.noreply.github.com>

mypy.ini

@@ -46,10 +46,6 @@ ignore_errors = True
 
 ignore_errors = True
 
-[mypy-torchvision.models.detection.generalized_rcnn]
-
-ignore_errors = True
-
 [mypy-torchvision.models.detection.faster_rcnn]
 
 ignore_errors = True

torchvision/models/detection/generalized_rcnn.py

@@ -25,7 +25,7 @@ class GeneralizedRCNN(nn.Module):
             the model
     """
 
-    def __init__(self, backbone, rpn, roi_heads, transform):
+    def __init__(self, backbone: nn.Module, rpn: nn.Module, roi_heads: nn.Module, transform: nn.Module) -> None:
         super().__init__()
         _log_api_usage_once(self)
         self.transform = transform
@@ -36,19 +36,26 @@ class GeneralizedRCNN(nn.Module):
         self._has_warned = False
 
     @torch.jit.unused
-    def eager_outputs(self, losses, detections):
-        # type: (Dict[str, Tensor], List[Dict[str, Tensor]]) -> Union[Dict[str, Tensor], List[Dict[str, Tensor]]]
+    def eager_outputs(
+        self,
+        losses: Dict[str, Tensor],
+        detections: List[Dict[str, Tensor]],
+    ) -> Union[Dict[str, Tensor], List[Dict[str, Tensor]]]:
+
         if self.training:
             return losses
 
         return detections
 
-    def forward(self, images, targets=None):
-        # type: (List[Tensor], Optional[List[Dict[str, Tensor]]]) -> Tuple[Dict[str, Tensor], List[Dict[str, Tensor]]]
+    def forward(
+        self,
+        images: List[Tensor],
+        targets: Optional[List[Dict[str, Tensor]]] = None,
+    ) -> Union[Tuple[Dict[str, Tensor], List[Dict[str, Tensor]]], Dict[str, Tensor], List[Dict[str, Tensor]]]:
         """
         Args:
             images (list[Tensor]): images to be processed
-            targets (list[Dict[Tensor]]): ground-truth boxes present in the image (optional)
+            targets (list[Dict[str, Tensor]]): ground-truth boxes present in the image (optional)
 
         Returns:
             result (list[BoxList] or dict[Tensor]): the output from the model.
@@ -97,7 +104,7 @@ class GeneralizedRCNN(nn.Module):
             features = OrderedDict([("0", features)])
         proposals, proposal_losses = self.rpn(images, features, targets)
         detections, detector_losses = self.roi_heads(features, proposals, images.image_sizes, targets)
-        detections = self.transform.postprocess(detections, images.image_sizes, original_image_sizes)
+        detections = self.transform.postprocess(detections, images.image_sizes, original_image_sizes)  # type: ignore[operator]
 
         losses = {}
         losses.update(detector_losses)