From b6d393ff7ad71e72797235d910a73cc7907be0e7 Mon Sep 17 00:00:00 2001
From: Jesper Friis <jesper.friis@sintef.no>
Date: Sun, 10 Sep 2023 17:39:28 +0200
Subject: [PATCH 1/3] Fixed issue with creating metadata.

Added test that both tests creation of metadata and that it is possible to
create two metadata with ref-properties that cyclic refer to each other.
---
 bindings/python/dlite-entity-python.i    |  3 +++
 bindings/python/tests/test_ref_create.py | 24 ++++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 bindings/python/tests/test_ref_create.py

diff --git a/bindings/python/dlite-entity-python.i b/bindings/python/dlite-entity-python.i
index 0ede8394e..f713d16b6 100644
--- a/bindings/python/dlite-entity-python.i
+++ b/bindings/python/dlite-entity-python.i
@@ -39,6 +39,9 @@ class Metadata(Instance):
         return Instance.create_metadata(
             uri, dimensions, properties, description)
 
+    def __init__(self, *args, **kwargs):
+        pass  # do nothing, just avoid calling Instance.__init__()
+
     def __repr__(self):
         return f"<Metadata: uri='{self.uri}'>"
 
diff --git a/bindings/python/tests/test_ref_create.py b/bindings/python/tests/test_ref_create.py
new file mode 100644
index 000000000..4ae87646f
--- /dev/null
+++ b/bindings/python/tests/test_ref_create.py
@@ -0,0 +1,24 @@
+import dlite
+
+
+# Create two entities with ref properties that cyclic refer to each other...
+prop_a = dlite.Property("a", "ref", "http://onto-ns.com/meta/0.1/A")
+B = dlite.Metadata(
+    "http://onto-ns.com/meta/0.1/B", dimensions=[], properties=[prop_a],
+)
+
+prop_v = dlite.Property("v", "int")
+prop_b = dlite.Property("b", "ref", "http://onto-ns.com/meta/0.1/B")
+A = dlite.Metadata(
+    "http://onto-ns.com/meta/0.1/A", dimensions=[], properties=[prop_v, prop_b],
+)
+
+# Create instances
+b = B()
+a = A(properties={"v": 3, "b": b})
+b.a = a
+
+
+assert a.v == 3
+assert a.b == b
+assert b.a == a

From 829305f9a31510d55daef3e2e5a5a55d6ac1f247 Mon Sep 17 00:00:00 2001
From: Jesper Friis <jesper-friis@users.noreply.github.com>
Date: Wed, 18 Oct 2023 11:39:11 +0200
Subject: [PATCH 2/3] Apply suggestions from code review

Co-authored-by: Anders Eklund <96499163+ajeklund@users.noreply.github.com>
---
 bindings/python/tests/test_ref_create.py | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/bindings/python/tests/test_ref_create.py b/bindings/python/tests/test_ref_create.py
index 4ae87646f..fcde12652 100644
--- a/bindings/python/tests/test_ref_create.py
+++ b/bindings/python/tests/test_ref_create.py
@@ -1,7 +1,7 @@
 import dlite
 
 
-# Create two entities with ref properties that cyclic refer to each other...
+# Create two entities (with ref properties) that cyclically refer to each other.
 prop_a = dlite.Property("a", "ref", "http://onto-ns.com/meta/0.1/A")
 B = dlite.Metadata(
     "http://onto-ns.com/meta/0.1/B", dimensions=[], properties=[prop_a],
@@ -14,11 +14,11 @@
 )
 
 # Create instances
-b = B()
-a = A(properties={"v": 3, "b": b})
-b.a = a
+inst_b = B()
+inst_a = A(properties={"v": 3, "b": inst_b})
+inst_b.a = inst_a
 
 
-assert a.v == 3
-assert a.b == b
-assert b.a == a
+assert inst_a.v == 3
+assert inst_a.b == inst_b
+assert inst_b.a == inst_a

From 0bc0a774c12636a3933f54eccd4a6107d3c5fa5e Mon Sep 17 00:00:00 2001
From: Jesper Friis <jesper.friis@sintef.no>
Date: Wed, 18 Oct 2023 14:04:00 +0200
Subject: [PATCH 3/3] Added comment suggested by reviewer

---
 bindings/python/dlite-entity-python.i | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/bindings/python/dlite-entity-python.i b/bindings/python/dlite-entity-python.i
index f713d16b6..51301a0aa 100644
--- a/bindings/python/dlite-entity-python.i
+++ b/bindings/python/dlite-entity-python.i
@@ -40,7 +40,12 @@ class Metadata(Instance):
             uri, dimensions, properties, description)
 
     def __init__(self, *args, **kwargs):
-        pass  # do nothing, just avoid calling Instance.__init__()
+        # Do nothing, just avoid calling Instance.__init__()
+        #
+        # The reason for this is that Instance.__init__() requires that the
+        # first argument is a dlite.Instance object ().  All needed
+        # instantiation is already done in __new__().
+        pass
 
     def __repr__(self):
         return f"<Metadata: uri='{self.uri}'>"