Apply StacIO instance from root in Catalog.set_root

CHANGELOG.md

@@ -13,6 +13,9 @@
 - Enable [strict
   mode](https://mypy.readthedocs.io/en/latest/command_line.html?highlight=strict%20mode#cmdoption-mypy-strict)
   for `mypy` ([#591](https://github.com/stac-utils/pystac/pull/591))
+- `Catalog.set_root` also sets `Catalog.stac_io` for the calling instance to be the same
+  as `root.stac_io`, if that value is not `None`
+  ([#590](https://github.com/stac-utils/pystac/pull/590))
 - Links will get their `title` from their target if no `title` is provided ([#607](https://github.com/stac-utils/pystac/pull/607))
 
 ### Fixed

pystac/catalog.py

@@ -45,7 +45,7 @@ class CatalogType(str, Enum):
 
     See:
         :stac-spec:`The best practices documentation on self-contained catalogs
-            <best-practices.md#self-contained-catalogs>`
+        <best-practices.md#self-contained-catalogs>`
     """
 
     ABSOLUTE_PUBLISHED = "ABSOLUTE_PUBLISHED"
@@ -55,7 +55,7 @@ class CatalogType(str, Enum):
 
     See:
         :stac-spec:`The best practices documentation on published catalogs
-            <best-practices.md#published-catalogs>`
+        <best-practices.md#published-catalogs>`
     """
 
     RELATIVE_PUBLISHED = "RELATIVE_PUBLISHED"
@@ -65,7 +65,7 @@ class CatalogType(str, Enum):
 
     See:
         :stac-spec:`The best practices documentation on published catalogs
-            <best-practices.md#published-catalogs>`
+        <best-practices.md#published-catalogs>`
     """
 
     @classmethod
@@ -181,11 +181,13 @@ def __repr__(self) -> str:
         return "<Catalog id={}>".format(self.id)
 
     def set_root(self, root: Optional["Catalog"]) -> None:
-        STACObject.set_root(self, root)
+        super().set_root(root)
         if root is not None:
             root._resolved_objects = ResolvedObjectCache.merge(
                 root._resolved_objects, self._resolved_objects
             )
+            if root._stac_io is not None:
+                self._stac_io = root._stac_io
 
     def is_relative(self) -> bool:
         return self.catalog_type in [

tests/test_catalog.py

@@ -18,6 +18,7 @@
     HIERARCHICAL_LINKS,
 )
 from pystac.extensions.label import LabelClasses, LabelExtension, LabelType
+from pystac.stac_io import DefaultStacIO
 from pystac.utils import is_absolute_href, join_path_or_url, JoinType
 from tests.utils import (
     TestCases,
@@ -107,6 +108,19 @@ def test_from_dict_set_root(self) -> None:
         collection = Catalog.from_dict(cat_dict, root=root_cat)
         self.assertIs(collection.get_root(), root_cat)
 
+    def test_from_dict_uses_root_stac_io(self) -> None:
+        class CustomStacIO(DefaultStacIO):
+            pass
+
+        path = TestCases.get_path("data-files/catalogs/test-case-1/catalog.json")
+        with open(path) as f:
+            cat_dict = json.load(f)
+        root_cat = pystac.Catalog(id="test", description="test desc")
+        root_cat._stac_io = CustomStacIO()
+
+        collection = Catalog.from_dict(cat_dict, root=root_cat)
+        self.assertIsInstance(collection._stac_io, CustomStacIO)
+
     def test_read_remote(self) -> None:
         # TODO: Move this URL to the main stac-spec repo once the example JSON is fixed.
         catalog_url = (