From b10a530d20aed80a5b0fe1a14cde81a4920c7bef Mon Sep 17 00:00:00 2001
From: Justin Chu <justinchuby@users.noreply.github.com>
Date: Wed, 23 Apr 2025 15:23:56 -0700
Subject: [PATCH 1/3] Invalid output

---
 onnxscript/ir/serde.py | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/onnxscript/ir/serde.py b/onnxscript/ir/serde.py
index bf39c1ea31..54177a44b2 100644
--- a/onnxscript/ir/serde.py
+++ b/onnxscript/ir/serde.py
@@ -672,8 +672,27 @@ def _deserialize_graph(
         for node in proto.node
     ]
 
-    # Fill in values for graph outputs
-    outputs = [deserialize_value_info_proto(info, values[info.name]) for info in proto.output]
+    outputs = []
+    for info in proto.output:
+        # Fill in values for graph outputs
+        output_name = info.name
+        if output_name not in values:
+            # Handle (invalid) graph outputs that do not have any producers
+            logger.warning(
+                "Output '%s' is not produced by any node. The graph has an invalid output",
+                output_name
+            )
+            value = _core.Value(name=output_name)
+            # Fill in shape/type information
+            deserialize_value_info_proto(info, value)
+            if output_name in quantization_annotations:
+                _deserialize_quantization_annotation(
+                    quantization_annotations[output_name], value
+                )
+        else:
+            # A valid, normal graph output
+            value = values[output_name]
+        outputs.append(value)
 
     # Exit the graph scope by popping the values for this scope from the stack
     scoped_values.pop()

From a57d6204556efeccbd109ec5cf80175d149f2478 Mon Sep 17 00:00:00 2001
From: Justin Chu <justinchuby@users.noreply.github.com>
Date: Wed, 23 Apr 2025 15:30:30 -0700
Subject: [PATCH 2/3] [IR] Handle invalid outputs

---
 onnxscript/ir/serde.py      |  2 +-
 onnxscript/ir/serde_test.py | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/onnxscript/ir/serde.py b/onnxscript/ir/serde.py
index 54177a44b2..b165536513 100644
--- a/onnxscript/ir/serde.py
+++ b/onnxscript/ir/serde.py
@@ -680,7 +680,7 @@ def _deserialize_graph(
             # Handle (invalid) graph outputs that do not have any producers
             logger.warning(
                 "Output '%s' is not produced by any node. The graph has an invalid output",
-                output_name
+                output_name,
             )
             value = _core.Value(name=output_name)
             # Fill in shape/type information
diff --git a/onnxscript/ir/serde_test.py b/onnxscript/ir/serde_test.py
index 416020afeb..303f02761f 100644
--- a/onnxscript/ir/serde_test.py
+++ b/onnxscript/ir/serde_test.py
@@ -290,6 +290,23 @@ def test_deserialize_graph_handles_unsorted_graph(self):
         self.assertEqual(deserialized_graph[0].op_type, "Op_1")
         self.assertEqual(deserialized_graph[1].op_type, "Op_0")
 
+    def test_deserialize_graph_handles_invalid_output(self):
+        # The graph has an output that is not connected to any node, and it does not
+        # have shape/type information.
+        graph_with_invalid_output = ir.Graph(
+            inputs=[],
+            outputs=[ir.Value(name="invalid_output")],
+            nodes=[],
+            name="graph_with_invalid_output",
+        )
+        graph_proto = serde.serialize_graph(graph_with_invalid_output)
+        deserialized_graph = serde.deserialize_graph(graph_proto)
+        self.assertEqual(len(deserialized_graph.outputs), 1)
+        self.assertEqual(deserialized_graph.outputs[0].name, "invalid_output")
+        self.assertEqual(deserialized_graph.outputs[0].type, None)
+        self.assertEqual(deserialized_graph.outputs[0].shape, None)
+        self.assertEqual(deserialized_graph.outputs[0].dtype, None)
+
 
 class QuantizationAnnotationTest(unittest.TestCase):
     """Test that quantization annotations are correctly serialized and deserialized."""

From 05cd67e704ccc60bc8afc307e3355adce46d22ba Mon Sep 17 00:00:00 2001
From: Justin Chu <justinchuby@users.noreply.github.com>
Date: Wed, 23 Apr 2025 15:50:25 -0700
Subject: [PATCH 3/3] deserialize_value_info_proto

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

diff --git a/onnxscript/ir/serde.py b/onnxscript/ir/serde.py
index b165536513..64703b2baa 100644
--- a/onnxscript/ir/serde.py
+++ b/onnxscript/ir/serde.py
@@ -683,15 +683,11 @@ def _deserialize_graph(
                 output_name,
             )
             value = _core.Value(name=output_name)
-            # Fill in shape/type information
-            deserialize_value_info_proto(info, value)
-            if output_name in quantization_annotations:
-                _deserialize_quantization_annotation(
-                    quantization_annotations[output_name], value
-                )
         else:
             # A valid, normal graph output
             value = values[output_name]
+        # Fill in shape/type information
+        deserialize_value_info_proto(info, value)
         outputs.append(value)
 
     # Exit the graph scope by popping the values for this scope from the stack