From 2e5316232e282c696fe9801eaf2b247c60f8456a Mon Sep 17 00:00:00 2001
From: Kent Mewhort <kent@openissues.ca>
Date: Wed, 4 Jun 2025 06:46:59 -0400
Subject: [PATCH] Fix IS_CHANGED for marking node as not changed

---
 comfy_execution/caching.py        | 20 ++++++++++++++++----
 tests/inference/test_execution.py | 30 ++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/comfy_execution/caching.py b/comfy_execution/caching.py
index dbb37b89f..05b57b1bb 100644
--- a/comfy_execution/caching.py
+++ b/comfy_execution/caching.py
@@ -93,11 +93,18 @@ class CacheKeySetInputSignature(CacheKeySet):
             self.subcache_keys[node_id] = (node_id, node["class_type"])
 
     def get_node_signature(self, dynprompt, node_id):
+        node = dynprompt.get_node(node_id)
+        class_type = node["class_type"]
+        class_def = nodes.NODE_CLASS_MAPPINGS[class_type]
+
         signature = []
-        ancestors, order_mapping = self.get_ordered_ancestry(dynprompt, node_id)
-        signature.append(self.get_immediate_node_signature(dynprompt, node_id, order_mapping))
-        for ancestor_id in ancestors:
-            signature.append(self.get_immediate_node_signature(dynprompt, ancestor_id, order_mapping))
+        if hasattr(class_def, "IS_CHANGED"):
+            signature.append(self.get_immediate_node_signature(dynprompt, node_id, {}))
+        else:
+            ancestors, order_mapping = self.get_ordered_ancestry(dynprompt, node_id)
+            signature.append(self.get_immediate_node_signature(dynprompt, node_id, order_mapping))
+            for ancestor_id in ancestors:
+                signature.append(self.get_immediate_node_signature(dynprompt, ancestor_id, order_mapping))
         return to_hashable(signature)
 
     def get_immediate_node_signature(self, dynprompt, node_id, ancestor_order_mapping):
@@ -108,8 +115,13 @@ class CacheKeySetInputSignature(CacheKeySet):
         class_type = node["class_type"]
         class_def = nodes.NODE_CLASS_MAPPINGS[class_type]
         signature = [class_type, self.is_changed_cache.get(node_id)]
+
         if self.include_node_id_in_input() or (hasattr(class_def, "NOT_IDEMPOTENT") and class_def.NOT_IDEMPOTENT) or include_unique_id_in_input(class_type):
             signature.append(node_id)
+
+        if hasattr(class_def, "IS_CHANGED"):
+            return signature
+
         inputs = node["inputs"]
         for key in sorted(inputs.keys()):
             if is_link(inputs[key]):
diff --git a/tests/inference/test_execution.py b/tests/inference/test_execution.py
index 5cda5c1ae..a31b9e7d7 100644
--- a/tests/inference/test_execution.py
+++ b/tests/inference/test_execution.py
@@ -497,6 +497,36 @@ class TestExecution:
         assert numpy.array(images[0]).min() == 63 and numpy.array(images[0]).max() == 63, "Image should have value 0.25"
         assert not result.did_run(test_node), "The execution should have been cached"
 
+    # This tests that a node does not re-execute when IS_CHANGED returs the same value (even if
+    # inputs change)
+    def test_is_changed_overrides_default_checks(self, client: ComfyClient, builder: GraphBuilder):
+        g = builder
+        changing_input = g.node("StubImage", content="BLACK", height=512, width=512, batch_size=1)
+        test_node = g.node("TestCustomIsChanged", should_change=False, image=changing_input.out(0))
+        g.node("SaveImage", images=test_node.out(0))
+
+        result1 = client.run(g)
+        assert result1.did_run(test_node), "Node should run on first execution"
+        assert result1.did_run(changing_input), "Input should run on first execution"
+
+        changing_input.set_input('content', "WHITE")  # Change input content
+
+        result2 = client.run(g)
+        assert result2.did_run(changing_input), "Input should re-execute due to content change"
+        assert not result2.did_run(test_node), "Node with IS_CHANGED should NOT re-execute when IS_CHANGED is consistent"
+
+        #  verify the behavior when IS_CHANGED actually changes
+        test_node.set_input('should_change', True)  # This should cause IS_CHANGED to return different value
+
+        result3 = client.run(g)
+        assert result3.did_run(test_node), "Node should re-execute when IS_CHANGED value actually changes"
+
+        changing_input.set_input('content', "BLACK")  # Change input back
+
+        result4 = client.run(g)
+        assert result4.did_run(changing_input), "Input should re-execute due to content change"
+        assert result4.did_run(test_node), "Node should re-execute because IS_CHANGED returns changing value (NaN)"
+
     # This tests that nodes with OUTPUT_IS_LIST function correctly when they receive an ExecutionBlocker
     # as input. We also test that when that list (containing an ExecutionBlocker) is passed to a node,
     # only that one entry in the list is blocked.