fix: remove duplicate self links on items

pystac/item.py

@@ -476,14 +476,9 @@ def from_dict(
             assets={k: Asset.from_dict(v) for k, v in assets.items()},
         )
 
-        has_self_link = False
         for link in links:
-            has_self_link |= link["rel"] == pystac.RelType.SELF
             item.add_link(Link.from_dict(link))
 
-        if not has_self_link and href is not None:
-            item.add_link(Link.self_href(href))
-
         if root:
             item.set_root(root)
 

tests/conftest.py

@@ -33,3 +33,8 @@ def test_case_1_catalog() -> Catalog:
 def projection_landsat8_item() -> Item:
     path = TestCases.get_path("data-files/projection/example-landsat8.json")
     return Item.from_file(path)
+
+
+@pytest.fixture
+def sample_item() -> Item:
+    return Item.from_file(TestCases.get_path("data-files/item/sample-item.json"))

tests/test_item.py

@@ -468,3 +468,8 @@ def test_geo_interface() -> None:
         item.to_dict(include_self_link=False, transform_hrefs=False)
         == item.__geo_interface__
     )
+
+
+def test_duplicate_self_links(sample_item: pystac.Item) -> None:
+    # https://github.com/stac-utils/pystac/issues/1102
+    assert len(sample_item.get_links(rel="self")) == 1