From 9ce89fc842d2280e63ab4048b3cac424a115033d Mon Sep 17 00:00:00 2001
From: Justus Magin <keewis@posteo.de>
Date: Wed, 9 Nov 2022 16:43:51 +0100
Subject: [PATCH 1/4] allow passing `DataTree` objects as `dict` values

---
 datatree/datatree.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/datatree/datatree.py b/datatree/datatree.py
index ff7a417b..8882bcc3 100644
--- a/datatree/datatree.py
+++ b/datatree/datatree.py
@@ -754,7 +754,7 @@ def update(self, other: Dataset | Mapping[str, DataTree | DataArray]) -> None:
     @classmethod
     def from_dict(
         cls,
-        d: MutableMapping[str, Dataset | DataArray | None],
+        d: MutableMapping[str, Dataset | DataArray | DataTree | None],
         name: str = None,
     ) -> DataTree:
         """
@@ -790,7 +790,11 @@ def from_dict(
             for path, data in d.items():
                 # Create and set new node
                 node_name = NodePath(path).name
-                new_node = cls(name=node_name, data=data)
+                if isinstance(data, cls):
+                    new_node = data.copy()
+                    new_node.orphan()
+                else:
+                    new_node = cls(name=node_name, data=data)
                 obj._set_item(
                     path,
                     new_node,

From 748f379a1f257dc78b44017de2bbbd0cfc8a1b30 Mon Sep 17 00:00:00 2001
From: Justus Magin <keewis@posteo.de>
Date: Wed, 9 Nov 2022 16:52:16 +0100
Subject: [PATCH 2/4] add a test verifying that DataTree objects are actually
 allowed

---
 datatree/tests/test_datatree.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/datatree/tests/test_datatree.py b/datatree/tests/test_datatree.py
index dd08618d..f5d7b928 100644
--- a/datatree/tests/test_datatree.py
+++ b/datatree/tests/test_datatree.py
@@ -391,6 +391,15 @@ def test_full(self, simple_datatree):
             "/set3",
         ]
 
+    def test_datatree_values(self):
+        dat1 = DataTree(data=xr.Dataset({"a": 1}))
+        expected = DataTree()
+        expected["a"] = dat1
+
+        actual = DataTree.from_dict({"a": dat1})
+
+        dtt.assert_identical(actual, expected)
+
     def test_roundtrip(self, simple_datatree):
         dt = simple_datatree
         roundtrip = DataTree.from_dict(dt.to_dict())

From 2d501b93c91185a62efcc55d08bd4a404d666467 Mon Sep 17 00:00:00 2001
From: Thomas Nicholas <thomas.nicholas@columbia.edu>
Date: Wed, 7 Dec 2022 14:20:33 -0500
Subject: [PATCH 3/4] ignore mypy error with copied copy method

---
 datatree/datatree.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/datatree/datatree.py b/datatree/datatree.py
index b042d41b..5d588da1 100644
--- a/datatree/datatree.py
+++ b/datatree/datatree.py
@@ -791,7 +791,8 @@ def from_dict(
                 # Create and set new node
                 node_name = NodePath(path).name
                 if isinstance(data, cls):
-                    new_node = data.copy()
+                    # TODO ignoring type error only needed whilst .copy() method is copied from Dataset.copy().
+                    new_node = data.copy()  # type: ignore[attr-defined]
                     new_node.orphan()
                 else:
                     new_node = cls(name=node_name, data=data)

From b90d1086534b7b8c298840ad69006c16075da35a Mon Sep 17 00:00:00 2001
From: Thomas Nicholas <thomas.nicholas@columbia.edu>
Date: Wed, 7 Dec 2022 14:24:09 -0500
Subject: [PATCH 4/4] whatsnew

---
 docs/source/whats-new.rst | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/docs/source/whats-new.rst b/docs/source/whats-new.rst
index 8d9d6573..cfe73a50 100644
--- a/docs/source/whats-new.rst
+++ b/docs/source/whats-new.rst
@@ -37,6 +37,9 @@ Deprecations
 Bug fixes
 ~~~~~~~~~
 
+- Allow ``Datatree`` objects as values in :py:meth:`DataTree.from_dict` (:pull:`159`).
+  By `Justus Magin <https://github.com/keewis>`_.
+
 Documentation
 ~~~~~~~~~~~~~