Allow backbones not in backbones_supported - Maskformer Mask2Former (#24532)

Allow backbones not in backbones_supported

src/transformers/models/mask2former/configuration_mask2former.py

@@ -170,11 +170,19 @@ class Mask2FormerConfig(PretrainedConfig):
                 use_absolute_embeddings=False,
                 out_features=["stage1", "stage2", "stage3", "stage4"],
             )
-        elif isinstance(backbone_config, dict):
-            backbone_model_type = backbone_config.get("model_type")
+
+        if isinstance(backbone_config, dict):
+            backbone_model_type = backbone_config.pop("model_type")
             config_class = CONFIG_MAPPING[backbone_model_type]
             backbone_config = config_class.from_dict(backbone_config)
 
+        # verify that the backbone is supported
+        if backbone_config.model_type not in self.backbones_supported:
+            logger.warning_once(
+                f"Backbone {backbone_config.model_type} is not a supported model and may not be compatible with Mask2Former. "
+                f"Supported model types: {','.join(self.backbones_supported)}"
+            )
+
         self.backbone_config = backbone_config
         self.feature_size = feature_size
         self.mask_feature_size = mask_feature_size

src/transformers/models/maskformer/configuration_maskformer.py

@@ -129,19 +129,18 @@ class MaskFormerConfig(PretrainedConfig):
                 drop_path_rate=0.3,
                 out_features=["stage1", "stage2", "stage3", "stage4"],
             )
-        else:
-            # verify that the backbone is supported
-            backbone_model_type = (
-                backbone_config.pop("model_type") if isinstance(backbone_config, dict) else backbone_config.model_type
+
+        if isinstance(backbone_config, dict):
+            backbone_model_type = backbone_config.pop("model_type")
+            config_class = CONFIG_MAPPING[backbone_model_type]
+            backbone_config = config_class.from_dict(backbone_config)
+
+        # verify that the backbone is supported
+        if backbone_config.model_type not in self.backbones_supported:
+            logger.warning_once(
+                f"Backbone {backbone_config.model_type} is not a supported model and may not be compatible with MaskFormer. "
+                f"Supported model types: {','.join(self.backbones_supported)}"
             )
-            if backbone_model_type not in self.backbones_supported:
-                raise ValueError(
-                    f"Backbone {backbone_model_type} not supported, please use one of"
-                    f" {','.join(self.backbones_supported)}"
-                )
-            if isinstance(backbone_config, dict):
-                config_class = CONFIG_MAPPING[backbone_model_type]
-                backbone_config = config_class.from_dict(backbone_config)
 
         if decoder_config is None:
             # fall back to https://huggingface.co/facebook/detr-resnet-50