fix in the dark: use pkginit with self._collection_node_cache1

src/_pytest/main.py

@@ -559,7 +559,8 @@ def _collect(self, argpath, names):
                                 if isinstance(col[0], Package):
                                     self._collection_pkg_roots[parent] = col[0]
                                 # always store a list in the cache, matchnodes expects it
-                                self._collection_node_cache1[col[0].fspath] = [col[0]]
+                                assert col[0].fspath == pkginit, (col[0], col[0].fspath, pkginit)
+                                self._collection_node_cache1[pkginit] = [col[0]]
 
         # If it's a directory argument, recurse and look for any Subpackages.
         # Let the Package collector deal with subnodes, don't collect here.