caching nodes to improve performance

tests/test_nodes.py

@@ -1759,6 +1759,146 @@ def test_execution_engine_numeric_socket_coercion():
     print("  PASS\n")
 
 
+def test_execution_engine_caches_unchanged_nodes():
+    print("=== Test: ExecutionEngine caches unchanged nodes ===")
+    from backend.execution import ExecutionEngine
+    from backend.node_registry import register_node
+
+    @register_node(display_name="Test Cache Source")
+    class TestCacheSource:
+        calls = 0
+
+        @classmethod
+        def INPUT_TYPES(cls):
+            return {"required": {"value": ("FLOAT",)}}
+
+        RETURN_TYPES = ("FLOAT",)
+        RETURN_NAMES = ("value",)
+        FUNCTION = "process"
+        CATEGORY = "tests"
+
+        def process(self, value):
+            TestCacheSource.calls += 1
+            return (float(value),)
+
+    @register_node(display_name="Test Cache Downstream")
+    class TestCacheDownstream:
+        calls = 0
+
+        @classmethod
+        def INPUT_TYPES(cls):
+            return {"required": {"value": ("FLOAT",)}}
+
+        RETURN_TYPES = ("FLOAT",)
+        RETURN_NAMES = ("value",)
+        FUNCTION = "process"
+        CATEGORY = "tests"
+
+        def process(self, value):
+            TestCacheDownstream.calls += 1
+            return (float(value) * 2.0,)
+
+    TestCacheSource.calls = 0
+    TestCacheDownstream.calls = 0
+
+    engine = ExecutionEngine()
+    prompt = {
+        "1": {
+            "class_type": "TestCacheSource",
+            "inputs": {"value": 2.5},
+        },
+        "2": {
+            "class_type": "TestCacheDownstream",
+            "inputs": {"value": ["1", 0]},
+        },
+    }
+
+    first_timings = []
+    first_outputs = engine.execute(prompt, on_node_done=lambda node_id, elapsed_ms: first_timings.append((node_id, elapsed_ms)))
+    second_timings = []
+    second_outputs = engine.execute(prompt, on_node_done=lambda node_id, elapsed_ms: second_timings.append((node_id, elapsed_ms)))
+
+    assert first_outputs["2"] == (5.0,)
+    assert second_outputs["2"] == (5.0,)
+    assert TestCacheSource.calls == 1
+    assert TestCacheDownstream.calls == 1
+    assert {node_id for node_id, _ in second_timings} == {"1", "2"}
+    assert all(elapsed_ms == 0.0 for _, elapsed_ms in second_timings)
+
+    print("  PASS\n")
+
+
+def test_execution_engine_only_propagates_real_output_changes():
+    print("=== Test: ExecutionEngine propagates only real upstream output changes ===")
+    from backend.execution import ExecutionEngine
+    from backend.node_registry import register_node
+
+    @register_node(display_name="Test Quantized Source")
+    class TestQuantizedSource:
+        calls = 0
+
+        @classmethod
+        def INPUT_TYPES(cls):
+            return {"required": {"value": ("FLOAT",)}}
+
+        RETURN_TYPES = ("INT",)
+        RETURN_NAMES = ("value",)
+        FUNCTION = "process"
+        CATEGORY = "tests"
+
+        def process(self, value):
+            TestQuantizedSource.calls += 1
+            return (int(round(float(value))),)
+
+    @register_node(display_name="Test Quantized Downstream")
+    class TestQuantizedDownstream:
+        calls = 0
+
+        @classmethod
+        def INPUT_TYPES(cls):
+            return {"required": {"value": ("INT",)}}
+
+        RETURN_TYPES = ("FLOAT",)
+        RETURN_NAMES = ("value",)
+        FUNCTION = "process"
+        CATEGORY = "tests"
+
+        def process(self, value):
+            TestQuantizedDownstream.calls += 1
+            return (float(value) + 0.5,)
+
+    TestQuantizedSource.calls = 0
+    TestQuantizedDownstream.calls = 0
+
+    engine = ExecutionEngine()
+    prompt = {
+        "1": {
+            "class_type": "TestQuantizedSource",
+            "inputs": {"value": 1.2},
+        },
+        "2": {
+            "class_type": "TestQuantizedDownstream",
+            "inputs": {"value": ["1", 0]},
+        },
+    }
+
+    outputs_first = engine.execute(prompt)
+    assert outputs_first["2"] == (1.5,)
+
+    prompt["1"]["inputs"]["value"] = 1.3
+    outputs_second = engine.execute(prompt)
+    assert outputs_second["2"] == (1.5,)
+
+    prompt["1"]["inputs"]["value"] = 2.2
+    outputs_third = engine.execute(prompt)
+    assert outputs_third["2"] == (2.5,)
+
+    assert TestQuantizedSource.calls == 3
+    assert TestQuantizedDownstream.calls == 2
+
+    print("  PASS\n")
+
+
 # =========================================================================
 # Analysis — Cursors
 # =========================================================================