diff --git a/osbuild/objectstore.py b/osbuild/objectstore.py
index 34897531..d760ce00 100644
--- a/osbuild/objectstore.py
+++ b/osbuild/objectstore.py
@@ -73,12 +73,22 @@ class Object:
     @contextlib.contextmanager
     def open(self):
         """Open the directory and return the file descriptor"""
+        if self._base_path and not self._init:
+            path = self._base_path
+        else:
+            path = self._tree
+
         try:
-            fd = os.open(self.path, os.O_DIRECTORY)
+            fd = os.open(path, os.O_DIRECTORY)
             yield fd
         finally:
             os.close(fd)
 
+    def write(self) -> str:
+        """Return a path that can be written to"""
+        self.init()
+        return self._tree
+
     def store_tree(self, destination: str):
         """Store the tree at destination and reset itself
 
@@ -167,8 +177,8 @@ class ObjectStore:
             if base_id:
                 # if we were given a base id, resolve its path and set it
                 # as the base_path of the object
+                # NB: `obj` does not get initialized explicitly here
                 obj.base_path = self.resolve_ref(base_id)
-                obj.init()
 
             yield obj
 
diff --git a/osbuild/pipeline.py b/osbuild/pipeline.py
index bb7211da..8071fac6 100644
--- a/osbuild/pipeline.py
+++ b/osbuild/pipeline.py
@@ -272,7 +272,7 @@ class Pipeline:
                     try:
                         with object_store.new(self.tree_id, base_id=base) as tree:
                             for stage in self.stages[base_idx + 1:]:
-                                r = stage.run(tree.path,
+                                r = stage.run(tree.write(),
                                               self.runner,
                                               build_tree,
                                               store,
@@ -298,7 +298,7 @@ class Pipeline:
                             r = self.assembler.run(tree,
                                                    self.runner,
                                                    build_tree,
-                                                   output_dir=output_dir.path,
+                                                   output_dir=output_dir.write(),
                                                    interactive=interactive,
                                                    libdir=libdir,
                                                    var=store)
diff --git a/test/test_objectstore.py b/test/test_objectstore.py
index 1a3da965..c33e4fbc 100644
--- a/test/test_objectstore.py
+++ b/test/test_objectstore.py
@@ -25,7 +25,8 @@ class TestObjectStore(unittest.TestCase):
         with tempfile.TemporaryDirectory(dir="/var/tmp") as tmp:
             object_store = objectstore.ObjectStore(tmp)
             with object_store.new("a") as tree:
-                p = Path(f"{tree.path}/A")
+                path = tree.write()
+                p = Path(f"{path}/A")
                 p.touch()
 
             assert os.path.exists(f"{object_store.refs}/a")
@@ -35,9 +36,10 @@ class TestObjectStore(unittest.TestCase):
             assert len(os.listdir(f"{object_store.refs}/a/")) == 1
 
             with object_store.new("b") as tree:
-                p = Path(f"{tree.path}/A")
+                path = tree.write()
+                p = Path(f"{path}/A")
                 p.touch()
-                p = Path(f"{tree.path}/B")
+                p = Path(f"{path}/B")
                 p.touch()
 
             assert os.path.exists(f"{object_store.refs}/b")
@@ -51,12 +53,14 @@ class TestObjectStore(unittest.TestCase):
         with tempfile.TemporaryDirectory(dir="/var/tmp") as tmp:
             object_store = objectstore.ObjectStore(tmp)
             with object_store.new("a") as tree:
-                p = Path(f"{tree.path}/A")
+                path = tree.write()
+                p = Path(f"{path}/A")
                 p.touch()
 
             with object_store.new("b") as tree:
+                path = tree.write()
                 shutil.copy2(f"{object_store.refs}/a/A",
-                             f"{tree.path}/A")
+                             f"{path}/A")
 
             assert os.path.exists(f"{object_store.refs}/a")
             assert os.path.exists(f"{object_store.refs}/a/A")
@@ -70,10 +74,12 @@ class TestObjectStore(unittest.TestCase):
     def test_snapshot(self):
         object_store = objectstore.ObjectStore(self.store)
         with object_store.new("b") as tree:
-            p = Path(f"{tree.path}/A")
+            path = tree.write()
+            p = Path(f"{path}/A")
             p.touch()
             object_store.snapshot(tree, "a")
-            p = Path(f"{tree.path}/B")
+            path = tree.write()
+            p = Path(f"{path}/B")
             p.touch()
 
         # check the references exist