Bug 44266 - Unable to change variable values whilst debugging

https://github.com/mono/debugger-libs/commit/ac17c08938408abc7f5aaf0f862d83bbd2b56d42

1 files changed, 10 insertions, 4 deletions

diff --git a/mcs/class/Mono.Debugger.Soft/Mono.Debugger.Soft/VirtualMachine.cs b/mcs/class/Mono.Debugger.Soft/Mono.Debugger.Soft/VirtualMachine.cs
index 9d7c9881ab9..40b7d631556 100644
--- a/mcs/class/Mono.Debugger.Soft/Mono.Debugger.Soft/VirtualMachine.cs
+++ b/mcs/class/Mono.Debugger.Soft/Mono.Debugger.Soft/VirtualMachine.cs
@@ -665,7 +665,7 @@ namespace Mono.Debugger.Soft
 			return res;
 		}
 
-		internal ValueImpl EncodeValue (Value v) {
+		internal ValueImpl EncodeValue (Value v, List<Value> duplicates = null) {
 			if (v is PrimitiveValue) {
 				object val = (v as PrimitiveValue).Value;
 				if (val == null)
@@ -675,16 +675,22 @@ namespace Mono.Debugger.Soft
 			} else if (v is ObjectMirror) {
 				return new ValueImpl { Type = ElementType.Object, Objid = (v as ObjectMirror).Id };
 			} else if (v is StructMirror) {
-				return new ValueImpl { Type = ElementType.ValueType, Klass = (v as StructMirror).Type.Id, Fields = EncodeValues ((v as StructMirror).Fields) };
+				if (duplicates == null)
+					duplicates = new List<Value> ();
+				if (duplicates.Contains (v))
+					return new ValueImpl { Type = (ElementType)ValueTypeId.VALUE_TYPE_ID_NULL, Objid = 0 };
+				duplicates.Add (v);
+
+				return new ValueImpl { Type = ElementType.ValueType, Klass = (v as StructMirror).Type.Id, Fields = EncodeValues ((v as StructMirror).Fields, duplicates) };
 			} else {
 				throw new NotSupportedException ();
 			}
 		}
 
-		internal ValueImpl[] EncodeValues (IList<Value> values) {
+		internal ValueImpl[] EncodeValues (IList<Value> values, List<Value> duplicates = null) {
 			ValueImpl[] res = new ValueImpl [values.Count];
 			for (int i = 0; i < values.Count; ++i)
-				res [i] = EncodeValue (values [i]);
+				res [i] = EncodeValue (values [i], duplicates);
 			return res;
 		}