get accessories with set difference, and set empty in strip

Author: Ariana Barzinpour

odc/stac/_mdtools.py

@@ -660,7 +660,6 @@ def parse_item(
     band2grid = template.band2grid
     has_proj = False if template.has_proj is False else has_proj_ext(item)
     _assets = item.assets
-    _acc_names = list(_assets.keys())
 
     _grids: Dict[str, GeoBox] = {}
     bands: Dict[BandKey, RasterSource] = {}
@@ -677,14 +676,13 @@ def _get_grid(grid_name: str, asset: pystac.asset.Asset) -> GeoBox:
         _grids[grid_name] = grid
         return grid
 
+    band_names = []
     for bk, meta in template.meta.bands.items():
         asset_name, band_idx = bk
         asset = _assets.get(asset_name)
         if asset is None:
             continue
-        # the assets that aren't bands should be accessories
-        if asset_name in _acc_names:
-            _acc_names.remove(asset_name)
+        band_names.append(asset_name)
 
         grid_name = band2grid.get(asset_name, "default")
         geobox: Optional[GeoBox] = _get_grid(grid_name, asset) if has_proj else None
@@ -715,7 +713,9 @@ def _get_grid(grid_name: str, asset: pystac.asset.Asset) -> GeoBox:
             driver_data=driver_data,
         )
 
-    accessories = {name: {"path": _assets[name].href} for name in _acc_names}
+    # the assets that aren't bands are accessories
+    acc_names = set(_assets.keys()).difference(set(band_names))
+    accessories = {name: {"path": _assets[name].href} for name in acc_names}
 
     md = item.common_metadata
     return ParsedItem(

odc/stac/model.py

@@ -400,7 +400,7 @@ def strip(self) -> "ParsedItem":
         """
         Copy of self but with stripped bands.
         """
-        return replace(self, bands={k: band.strip() for k, band in self.bands.items()})
+        return replace(self, bands={k: band.strip() for k, band in self.bands.items()}, accessories={})
 
     def assets(self) -> Dict[str, List[RasterSource]]:
         """

tests/test_mdtools.py

@@ -400,6 +400,7 @@ def test_accessories_preserved(ga_landsat_stac: pystac.item.Item):
     assert xx.accessories.get("thumbnail:nbart")
     assert xx.accessories.get("checksum:sha1")
     assert xx.accessories.get("metadata:processor")
+    assert xx.strip().accessories == {}
 
 
 @pytest.fixture