From 8a1abb5a615c15471efdd104c5d8681de60213b4 Mon Sep 17 00:00:00 2001
From: Brett <brettgraham@gmail.com>
Date: Wed, 14 Aug 2024 13:04:01 -0400
Subject: [PATCH 1/3] add _IgnoreCustomTagsLoader and use it in load_yaml

---
 asdf/_tests/test_util.py | 14 ++++++++++++++
 asdf/util.py             |  4 ++--
 asdf/yamlutil.py         | 23 +++++++++++++++++++++++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/asdf/_tests/test_util.py b/asdf/_tests/test_util.py
index e45d68eb7..ca64a7a41 100644
--- a/asdf/_tests/test_util.py
+++ b/asdf/_tests/test_util.py
@@ -145,3 +145,17 @@ def test_load_yaml(tmp_path, input_type, tagged):
         assert isinstance(tree["a"], asdf.tagged.TaggedDict)
     else:
         assert not isinstance(tree["a"], asdf.tagged.TaggedDict)
+
+
+@pytest.mark.parametrize("tagged", [True, False])
+def test_load_yaml_recursion(tmp_path, tagged):
+    fn = tmp_path / "test.asdf"
+    tree = {}
+    tree["d"] = {}
+    tree["d"]["d"] = tree["d"]
+    tree["l"] = []
+    tree["l"].append(tree["l"])
+    asdf.AsdfFile(tree).write_to(fn)
+    tree = util.load_yaml(fn, tagged=tagged)
+    assert tree["d"]["d"] is tree["d"]
+    assert tree["l"][0] is tree["l"]
diff --git a/asdf/util.py b/asdf/util.py
index bbd873d99..b099213bc 100644
--- a/asdf/util.py
+++ b/asdf/util.py
@@ -86,12 +86,12 @@ def load_yaml(init, tagged=False):
     """
 
     from .generic_io import get_file
-    from .yamlutil import AsdfLoader
+    from .yamlutil import AsdfLoader, _IgnoreCustomTagsLoader
 
     if tagged:
         loader = AsdfLoader
     else:
-        loader = yaml.CBaseLoader if getattr(yaml, "__with_libyaml__", None) else yaml.BaseLoader
+        loader = _IgnoreCustomTagsLoader
 
     with get_file(init, "r") as gf:
         reader = gf.reader_until(
diff --git a/asdf/yamlutil.py b/asdf/yamlutil.py
index 63c2d864a..718bfecc2 100644
--- a/asdf/yamlutil.py
+++ b/asdf/yamlutil.py
@@ -137,6 +137,29 @@ def represent_numpy_str(dumper, data):
 AsdfDumper.add_representer(np.bytes_, AsdfDumper.represent_binary)
 
 
+class _IgnoreCustomTagsLoader(_yaml_base_loader):
+    """
+    A specialized YAML loader that ignores tags unknown to the
+    base (safe) loader. This is used by `asdf.util.load_yaml`
+    to read the ASDF tree as "basic" objects, ignoring the
+    custom tags.
+    """
+
+    def construct_undefined(self, node):
+        if isinstance(node, yaml.MappingNode):
+            return self.construct_mapping(node)
+        elif isinstance(node, yaml.SequenceNode):
+            return self.construct_sequence(node)
+        elif isinstance(node, yaml.ScalarNode):
+            return self.construct_scalar(node)
+        return super().construct_undefined(node)
+
+
+# pyyaml will invoke the constructor associated with None when a node's
+# tag is not explicitly handled by another constructor.
+_IgnoreCustomTagsLoader.add_constructor(None, _IgnoreCustomTagsLoader.construct_undefined)
+
+
 class AsdfLoader(_yaml_base_loader):
     """
     A specialized YAML loader that can construct "tagged basic Python

From e1cdbbc0fb38bf91b04e71ae7381517d576bbdc3 Mon Sep 17 00:00:00 2001
From: Brett <brettgraham@gmail.com>
Date: Wed, 14 Aug 2024 13:06:32 -0400
Subject: [PATCH 2/3] add changelog

---
 changes/1819.bugfix.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changes/1819.bugfix.rst

diff --git a/changes/1819.bugfix.rst b/changes/1819.bugfix.rst
new file mode 100644
index 000000000..25782b574
--- /dev/null
+++ b/changes/1819.bugfix.rst
@@ -0,0 +1 @@
+Allow ``asdf.util.load_yaml`` to handle recursive objects

From 196156fc42e3a258ca6fe5bd27c2d3ef1c90404a Mon Sep 17 00:00:00 2001
From: Brett <brettgraham@gmail.com>
Date: Mon, 19 Aug 2024 16:03:43 -0400
Subject: [PATCH 3/3] fix changelog fragment name

---
 changes/{1819.bugfix.rst => 1825.bugfix.rst} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename changes/{1819.bugfix.rst => 1825.bugfix.rst} (100%)

diff --git a/changes/1819.bugfix.rst b/changes/1825.bugfix.rst
similarity index 100%
rename from changes/1819.bugfix.rst
rename to changes/1825.bugfix.rst