From 5d64310756dfb7a508b21836bc676d8144357b2f Mon Sep 17 00:00:00 2001
From: greateggsgreg <greateggsgreg@gmail.com>
Date: Sat, 9 May 2026 16:17:39 -0400
Subject: [PATCH] Propagate exceptions from TryGetMember in
 tp_getattro_dlr_proxy

The dynamic getter swallowed any exception from TryGetMember and
returned default to Python with the prior AttributeError still set,
so user code observed a misleading AttributeError instead of the real
failure.

Set a Python exception in the catch arm. We use RuntimeError with the
message string rather than Converter.ToPython(e) because wrapping the
CLR exception object can trigger type initialisation that re-enters
this same slot on the live dynamic object, producing infinite
recursion.

Mirrors the symmetry already present in the setter (#2706 review,
@lostmsu) and adds a regression test alongside the existing
ThrowingSetDynamicObject coverage.
---
 src/runtime/TypeManager.cs | 7 ++++++-
 src/testing/dlrtest.cs     | 6 ++++++
 tests/test_dynamic.py      | 9 +++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/runtime/TypeManager.cs b/src/runtime/TypeManager.cs
index 30a99690a..3b3c6db1a 100644
--- a/src/runtime/TypeManager.cs
+++ b/src/runtime/TypeManager.cs
@@ -123,8 +123,13 @@ public static NewReference tp_getattro_dlr_proxy(BorrowedReference ob, BorrowedR
             {
                 resolved = dynamicMemberAccessor.TryGetMember(dynamicObject, memberName, out value);
             }
-            catch
+            catch (Exception e)
             {
+                // Avoid wrapping the CLR exception via Converter.ToPython here: that would trigger
+                // CLR type initialisation which can re-enter this slot on the same live object,
+                // causing infinite recursion. A plain RuntimeError with the message is safe.
+                Runtime.PyErr_Clear();
+                Exceptions.SetError(Exceptions.RuntimeError, e.Message);
                 return default;
             }
 
diff --git a/src/testing/dlrtest.cs b/src/testing/dlrtest.cs
index b58f5fc82..783a3a133 100644
--- a/src/testing/dlrtest.cs
+++ b/src/testing/dlrtest.cs
@@ -62,6 +62,12 @@ public override bool TrySetMember(SetMemberBinder binder, object value)
     }
 }
 
+public class ThrowingGetDynamicObject : DynamicStorageObject
+{
+    public override bool TryGetMember(GetMemberBinder binder, out object result)
+        => throw new InvalidOperationException($"TryGetMember failed for '{binder.Name}'");
+}
+
 public class ThrowingSetDynamicObject : DynamicStorageObject
 {
     public override bool TrySetMember(SetMemberBinder binder, object value)
diff --git a/tests/test_dynamic.py b/tests/test_dynamic.py
index b8caa24b3..f093ee19a 100644
--- a/tests/test_dynamic.py
+++ b/tests/test_dynamic.py
@@ -8,6 +8,7 @@
 from Python.Test import RejectingDeleteDynamicObject
 from Python.Test import RejectingSetDynamicObject
 from Python.Test import ThrowingDeleteDynamicObject
+from Python.Test import ThrowingGetDynamicObject
 from Python.Test import ThrowingSetDynamicObject
 
 
@@ -186,6 +187,14 @@ def test_trysetmember_false_raises_attributeerror_instead_of_silent_python_setat
     assert not hasattr(obj, "typoed_name")
 
 
+def test_trygetmember_exception_is_raised_in_python():
+    obj = ThrowingGetDynamicObject()
+    obj.AddDynamicMember("any_key", 1)
+
+    with pytest.raises(Exception, match="TryGetMember failed for 'any_key'"):
+        _ = obj.any_key
+
+
 def test_trysetmember_exception_is_raised_in_python():
     obj = ThrowingSetDynamicObject()