Create valid dict without root href

CHANGELOG.md

@@ -18,6 +18,7 @@
 
 ### Fixed
 
+- Creating dictionaries from Catalogs and Collections without root hrefs now creates valid STAC ([#896](https://github.com/stac-utils/pystac/pull/896))
 - Dependency resolution when installing `requirements-dev.txt` ([#897](https://github.com/stac-utils/pystac/pull/897))
 - Serializing optional Collection attributes ([#916](https://github.com/stac-utils/pystac/pull/916))
 

pystac/catalog.py

@@ -498,7 +498,11 @@ def get_item_links(self) -> List[Link]:
     def to_dict(
         self, include_self_link: bool = True, transform_hrefs: bool = True
     ) -> Dict[str, Any]:
-        links = self.links
+        links = [
+            x
+            for x in self.links
+            if x.rel != pystac.RelType.ROOT or x.get_href(transform_hrefs) is not None
+        ]
         if not include_self_link:
             links = [x for x in links if x.rel != pystac.RelType.SELF]
 

tests/test_catalog.py

@@ -1252,6 +1252,11 @@ def test_get_links_media_type(self) -> None:
             len(catalog.get_links("search", media_type="application/geo+json")), 1
         )
 
+    def test_to_dict_no_self_href(self) -> None:
+        catalog = Catalog(id="an-id", description="A test Catalog")
+        d = catalog.to_dict(include_self_link=False)
+        Catalog.from_dict(d)
+
 
 class FullCopyTest(unittest.TestCase):
     def check_link(self, link: pystac.Link, tag: str) -> None:

tests/test_collection.py

@@ -346,6 +346,16 @@ def test_clone_preserves_assets(self) -> None:
                 with self.subTest(f"Sets owner for {key}"):
                     self.assertIs(cloned_asset.owner, cloned_collection)
 
+    def test_to_dict_no_self_href(self) -> None:
+        temporal_extent = TemporalExtent(intervals=[[TEST_DATETIME, None]])
+        spatial_extent = SpatialExtent(bboxes=ARBITRARY_BBOX)
+        extent = Extent(spatial=spatial_extent, temporal=temporal_extent)
+        collection = Collection(
+            id="an-id", description="A test Collection", extent=extent
+        )
+        d = collection.to_dict(include_self_link=False)
+        Collection.from_dict(d)
+
 
 class ExtentTest(unittest.TestCase):
     def setUp(self) -> None: