fix bug in setting state dict from relative path (SBU-BMI#123)

Fixes SBU-BMI#116

tests/test_all.py

@@ -818,12 +818,15 @@ def test_invalid_modeldefs(modeldef, tmp_path: Path):
 def test_valid_modeldefs(tmp_path: Path):
     from wsinfer._modellib.models import Weights
 
-    weights_file = tmp_path / "weights.pt"
+    # Put the weights in a different directory than the config to make sure that
+    # relative paths work.
+    weights_file = tmp_path / "ckpts" / "weights.pt"
+    weights_file.parent.mkdir()
     modeldef = dict(
         version="1.0",
         name="foo",
         architecture="resnet34",
-        file=str(weights_file),
+        file="ckpts/weights.pt",
         num_classes=2,
         transform=dict(resize_size=224, mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5]),
         patch_size_pixels=350,
@@ -838,7 +841,9 @@ def test_valid_modeldefs(tmp_path: Path):
         Weights.from_yaml(path)
 
     weights_file.touch()
-    assert Weights.from_yaml(path)
+    w = Weights.from_yaml(path)
+    assert w.file is not None
+    assert Path(w.file).exists()
 
 
 def test_model_registration(tmp_path: Path):

wsinfer/_modellib/models.py

@@ -173,22 +173,27 @@ def _validate_input(d: dict, config_path: Path) -> None:
     @classmethod
     def from_yaml(cls, path):
         """Create a new instance of Weights from a YAML file."""
+        path = Path(path)
 
         with open(path) as f:
             d = yaml.safe_load(f)
-        cls._validate_input(d, config_path=Path(path))
+        cls._validate_input(d, config_path=path)
 
         transform = PatchClassification(
             resize_size=d["transform"]["resize_size"],
             mean=d["transform"]["mean"],
             std=d["transform"]["std"],
         )
+        if d.get("file") is not None:
+            file = path.parent / d.get("file")
+        else:
+            file = None
         return Weights(
             name=d["name"],
             architecture=d["architecture"],
             url=d.get("url"),
             url_file_name=d.get("url_file_name"),
-            file=d.get("file"),
+            file=file,
             num_classes=d["num_classes"],
             transform=transform,
             patch_size_pixels=d["patch_size_pixels"],