Improve value renaming (#208)

Do not modify the value name if the new name is invalid. This makes the
setter of Value.name safer in that things will not be left in an
inconsistent state if a check fails

---------

Signed-off-by: Justin Chu <justinchuby@users.noreply.github.com>

Author: justinchuby

src/onnx_ir/_core.py

@@ -2214,23 +2214,38 @@ def name(self) -> str | None:
 
     @name.setter
     def name(self, value: str | None) -> None:
-        if self._const_value is not None:
-            self._const_value.name = value
-        old_name = self._name
-        self._name = value
-        if self.is_initializer():
+        if self._name == value:
+            return
+
+        # First check if renaming is valid. Do not change anything if it is invalid
+        # to prevent the value from being in an inconsistent state.
+        is_initializer = self.is_initializer()
+        if is_initializer:
             if value is None:
                 raise ValueError(
-                    "Initializer value cannot have name set to None. Please pop() the value from initializers first"
+                    "Initializer value cannot have name set to None. Please pop() the value from initializers first to do so."
                 )
-            # Rename the initializer entry in the graph
             graph = self._graph
             assert graph is not None
-            assert old_name is not None
             if value in graph.initializers and graph.initializers[value] is not self:
                 raise ValueError(
-                    f"Cannot rename initializer to '{value}': an initializer with that name already exists."
+                    f"Cannot rename initializer '{self}' to '{value}': an initializer with that name already exists."
                 )
+
+        # Rename the backing constant tensor
+        if self._const_value is not None:
+            self._const_value.name = value
+
+        # Rename self
+        old_name = self._name
+        self._name = value
+
+        if is_initializer:
+            # Rename the initializer entry in the graph
+            assert value is not None, "debug: Should be guarded above"
+            graph = self._graph
+            assert graph is not None
+            assert old_name is not None
             graph.initializers.pop(old_name)
             graph.initializers[value] = self
 

src/onnx_ir/_core_test.py

@@ -869,6 +869,9 @@ def test_initializer_name_setter_raises_when_set_to_none(self):
         ):
             value.name = None
 
+        # Name should remain unchanged
+        self.assertEqual(value.name, "initializer1")
+
     def test_initializer_name_setter_updates_graph_initializers_dict(self):
         """Test that renaming an initializer value updates the graph's initializers dictionary."""
         tensor = ir.tensor([1, 2, 3])