A little more refactoring

dkist/io/file_manager.py

@@ -97,14 +97,13 @@ def __init__(
         self.dtype = dtype
         self.target = target
         self._loader = loader
-        self._basepath = None
-        self.basepath = basepath  # Use the setter to convert to a Path
+        self._basepath = self._sanitize_basepath(basepath)
         self.chunksize = chunksize
         self._fileuri_array = np.atleast_1d(np.array(fileuris))
 
         loader_array = np.empty_like(self._fileuri_array, dtype=object)
         for i, fileuri in enumerate(self._fileuri_array.flat):
-            loader_array.flat[i] = loader(fileuri, shape, dtype, target, self)
+            loader_array.flat[i] = loader(fileuri, shape, dtype, target, self.basepath)
 
         self._loader_array = loader_array
 
@@ -125,13 +124,15 @@ def basepath(self) -> os.PathLike:
         """
         return self._basepath
 
+    @staticmethod
+    def _sanitize_basepath(value):
+        return Path(value).expanduser() if value is not None else None
+
     @basepath.setter
     def basepath(self, value: os.PathLike | str | None):
-        self._basepath = Path(value).expanduser() if value is not None else None
-        if hasattr(self, '_loader_array'):
-            # We get called during __init__ before _loader_array is created
-            for loader in self._loader_array.flat:
-                loader.basepath = self._basepath
+        self._basepath = self._sanitize_basepath(value)
+        for loader in self._loader_array.flat:
+            loader.basepath = self._basepath
 
     @property
     def fileuri_array(self) -> NDArray[str]:

dkist/io/loaders.py

@@ -45,12 +45,12 @@ class BaseFITSLoader(metaclass=abc.ABCMeta):
     time.
     """
 
-    def __init__(self, fileuri, shape, dtype, target, array_container):
+    def __init__(self, fileuri, shape, dtype, target, basepath):
         self.fileuri = fileuri
         self.shape = shape
         self.dtype = dtype
         self.target = target
-        self.basepath = array_container.basepath
+        self.basepath = basepath
         self.ndim = len(self.shape)
         self.size = np.prod(self.shape)