Execution Model Inversion (#2666)

* Execution Model Inversion

This PR inverts the execution model -- from recursively calling nodes to
using a topological sort of the nodes. This change allows for
modification of the node graph during execution. This allows for two
major advantages:

    1. The implementation of lazy evaluation in nodes. For example, if a
    "Mix Images" node has a mix factor of exactly 0.0, the second image
    input doesn't even need to be evaluated (and visa-versa if the mix
    factor is 1.0).

    2. Dynamic expansion of nodes. This allows for the creation of dynamic
    "node groups". Specifically, custom nodes can return subgraphs that
    replace the original node in the graph. This is an incredibly
    powerful concept. Using this functionality, it was easy to
    implement:
        a. Components (a.k.a. node groups)
        b. Flow control (i.e. while loops) via tail recursion
        c. All-in-one nodes that replicate the WebUI functionality
        d. and more
    All of those were able to be implemented entirely via custom nodes,
    so those features are *not* a part of this PR. (There are some
    front-end changes that should occur before that functionality is
    made widely available, particularly around variant sockets.)

The custom nodes associated with this PR can be found at:
https://github.com/BadCafeCode/execution-inversion-demo-comfyui

Note that some of them require that variant socket types ("*") be
enabled.

* Allow `input_info` to be of type `None`

* Handle errors (like OOM) more gracefully

* Add a command-line argument to enable variants

This allows the use of nodes that have sockets of type '*' without
applying a patch to the code.

* Fix an overly aggressive assertion.

This could happen when attempting to evaluate `IS_CHANGED` for a node
during the creation of the cache (in order to create the cache key).

* Fix Pyright warnings

* Add execution model unit tests

* Fix issue with unused literals

Behavior should now match the master branch with regard to undeclared
inputs. Undeclared inputs that are socket connections will be used while
undeclared inputs that are literals will be ignored.

* Make custom VALIDATE_INPUTS skip normal validation

Additionally, if `VALIDATE_INPUTS` takes an argument named `input_types`,
that variable will be a dictionary of the socket type of all incoming
connections. If that argument exists, normal socket type validation will
not occur. This removes the last hurdle for enabling variant types
entirely from custom nodes, so I've removed that command-line option.

I've added appropriate unit tests for these changes.

* Fix example in unit test

This wouldn't have caused any issues in the unit test, but it would have
bugged the UI if someone copy+pasted it into their own node pack.

* Use fstrings instead of '%' formatting syntax

* Use custom exception types.

* Display an error for dependency cycles

Previously, dependency cycles that were created during node expansion
would cause the application to quit (due to an uncaught exception). Now,
we'll throw a proper error to the UI. We also make an attempt to 'blame'
the most relevant node in the UI.

* Add docs on when ExecutionBlocker should be used

* Remove unused functionality

* Rename ExecutionResult.SLEEPING to PENDING

* Remove superfluous function parameter

* Pass None for uneval inputs instead of default

This applies to `VALIDATE_INPUTS`, `check_lazy_status`, and lazy values
in evaluation functions.

* Add a test for mixed node expansion

This test ensures that a node that returns a combination of expanded
subgraphs and literal values functions correctly.

* Raise exception for bad get_node calls.

* Minor refactor of IsChangedCache.get

* Refactor `map_node_over_list` function

* Fix ui output for duplicated nodes

* Add documentation on `check_lazy_status`

* Add file for execution model unit tests

* Clean up Javascript code as per review

* Improve documentation

Converted some comments to docstrings as per review

* Add a new unit test for mixed lazy results

This test validates that when an output list is fed to a lazy node, the
node will properly evaluate previous nodes that are needed by any inputs
to the lazy node.

No code in the execution model has been changed. The test already
passes.

* Allow kwargs in VALIDATE_INPUTS functions

When kwargs are used, validation is skipped for all inputs as if they
had been mentioned explicitly.

* List cached nodes in `execution_cached` message

This was previously just bugged in this PR.

tests/inference/testing_nodes/testing-pack/__init__.py

@@ -0,0 +1,23 @@
+from .specific_tests import TEST_NODE_CLASS_MAPPINGS, TEST_NODE_DISPLAY_NAME_MAPPINGS
+from .flow_control import FLOW_CONTROL_NODE_CLASS_MAPPINGS, FLOW_CONTROL_NODE_DISPLAY_NAME_MAPPINGS
+from .util import UTILITY_NODE_CLASS_MAPPINGS, UTILITY_NODE_DISPLAY_NAME_MAPPINGS
+from .conditions import CONDITION_NODE_CLASS_MAPPINGS, CONDITION_NODE_DISPLAY_NAME_MAPPINGS
+from .stubs import TEST_STUB_NODE_CLASS_MAPPINGS, TEST_STUB_NODE_DISPLAY_NAME_MAPPINGS
+
+# NODE_CLASS_MAPPINGS = GENERAL_NODE_CLASS_MAPPINGS.update(COMPONENT_NODE_CLASS_MAPPINGS)
+# NODE_DISPLAY_NAME_MAPPINGS = GENERAL_NODE_DISPLAY_NAME_MAPPINGS.update(COMPONENT_NODE_DISPLAY_NAME_MAPPINGS)
+
+NODE_CLASS_MAPPINGS = {}
+NODE_CLASS_MAPPINGS.update(TEST_NODE_CLASS_MAPPINGS)
+NODE_CLASS_MAPPINGS.update(FLOW_CONTROL_NODE_CLASS_MAPPINGS)
+NODE_CLASS_MAPPINGS.update(UTILITY_NODE_CLASS_MAPPINGS)
+NODE_CLASS_MAPPINGS.update(CONDITION_NODE_CLASS_MAPPINGS)
+NODE_CLASS_MAPPINGS.update(TEST_STUB_NODE_CLASS_MAPPINGS)
+
+NODE_DISPLAY_NAME_MAPPINGS = {}
+NODE_DISPLAY_NAME_MAPPINGS.update(TEST_NODE_DISPLAY_NAME_MAPPINGS)
+NODE_DISPLAY_NAME_MAPPINGS.update(FLOW_CONTROL_NODE_DISPLAY_NAME_MAPPINGS)
+NODE_DISPLAY_NAME_MAPPINGS.update(UTILITY_NODE_DISPLAY_NAME_MAPPINGS)
+NODE_DISPLAY_NAME_MAPPINGS.update(CONDITION_NODE_DISPLAY_NAME_MAPPINGS)
+NODE_DISPLAY_NAME_MAPPINGS.update(TEST_STUB_NODE_DISPLAY_NAME_MAPPINGS)
+

tests/inference/testing_nodes/testing-pack/conditions.py

@@ -0,0 +1,194 @@
+import re
+import torch
+
+class TestIntConditions:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "a": ("INT", {"default": 0, "min": -0xffffffffffffffff, "max": 0xffffffffffffffff, "step": 1}),
+                "b": ("INT", {"default": 0, "min": -0xffffffffffffffff, "max": 0xffffffffffffffff, "step": 1}),
+                "operation": (["==", "!=", "<", ">", "<=", ">="],),
+            },
+        }
+
+    RETURN_TYPES = ("BOOLEAN",)
+    FUNCTION = "int_condition"
+
+    CATEGORY = "Testing/Logic"
+
+    def int_condition(self, a, b, operation):
+        if operation == "==":
+            return (a == b,)
+        elif operation == "!=":
+            return (a != b,)
+        elif operation == "<":
+            return (a < b,)
+        elif operation == ">":
+            return (a > b,)
+        elif operation == "<=":
+            return (a <= b,)
+        elif operation == ">=":
+            return (a >= b,)
+
+
+class TestFloatConditions:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "a": ("FLOAT", {"default": 0, "min": -999999999999.0, "max": 999999999999.0, "step": 1}),
+                "b": ("FLOAT", {"default": 0, "min": -999999999999.0, "max": 999999999999.0, "step": 1}),
+                "operation": (["==", "!=", "<", ">", "<=", ">="],),
+            },
+        }
+
+    RETURN_TYPES = ("BOOLEAN",)
+    FUNCTION = "float_condition"
+
+    CATEGORY = "Testing/Logic"
+
+    def float_condition(self, a, b, operation):
+        if operation == "==":
+            return (a == b,)
+        elif operation == "!=":
+            return (a != b,)
+        elif operation == "<":
+            return (a < b,)
+        elif operation == ">":
+            return (a > b,)
+        elif operation == "<=":
+            return (a <= b,)
+        elif operation == ">=":
+            return (a >= b,)
+
+class TestStringConditions:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "a": ("STRING", {"multiline": False}),
+                "b": ("STRING", {"multiline": False}),
+                "operation": (["a == b", "a != b", "a IN b", "a MATCH REGEX(b)", "a BEGINSWITH b", "a ENDSWITH b"],),
+                "case_sensitive": ("BOOLEAN", {"default": True}),
+            },
+        }
+
+    RETURN_TYPES = ("BOOLEAN",)
+    FUNCTION = "string_condition"
+
+    CATEGORY = "Testing/Logic"
+
+    def string_condition(self, a, b, operation, case_sensitive):
+        if not case_sensitive:
+            a = a.lower()
+            b = b.lower()
+
+        if operation == "a == b":
+            return (a == b,)
+        elif operation == "a != b":
+            return (a != b,)
+        elif operation == "a IN b":
+            return (a in b,)
+        elif operation == "a MATCH REGEX(b)":
+            try:
+                return (re.match(b, a) is not None,)
+            except:
+                return (False,)
+        elif operation == "a BEGINSWITH b":
+            return (a.startswith(b),)
+        elif operation == "a ENDSWITH b":
+            return (a.endswith(b),)
+
+class TestToBoolNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "value": ("*",),
+            },
+            "optional": {
+                "invert": ("BOOLEAN", {"default": False}),
+            },
+        }
+
+    RETURN_TYPES = ("BOOLEAN",)
+    FUNCTION = "to_bool"
+
+    CATEGORY = "Testing/Logic"
+
+    def to_bool(self, value, invert = False):
+        if isinstance(value, torch.Tensor):
+            if value.max().item() == 0 and value.min().item() == 0:
+                result = False
+            else:
+                result = True
+        else:
+            try:
+                result = bool(value)
+            except:
+                # Can't convert it? Well then it's something or other. I dunno, I'm not a Python programmer.
+                result = True
+
+        if invert:
+            result = not result
+
+        return (result,)
+
+class TestBoolOperationNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "a": ("BOOLEAN",),
+                "b": ("BOOLEAN",),
+                "op": (["a AND b", "a OR b", "a XOR b", "NOT a"],),
+            },
+        }
+
+    RETURN_TYPES = ("BOOLEAN",)
+    FUNCTION = "bool_operation"
+
+    CATEGORY = "Testing/Logic"
+
+    def bool_operation(self, a, b, op):
+        if op == "a AND b":
+            return (a and b,)
+        elif op == "a OR b":
+            return (a or b,)
+        elif op == "a XOR b":
+            return (a ^ b,)
+        elif op == "NOT a":
+            return (not a,)
+
+
+CONDITION_NODE_CLASS_MAPPINGS = {
+    "TestIntConditions": TestIntConditions,
+    "TestFloatConditions": TestFloatConditions,
+    "TestStringConditions": TestStringConditions,
+    "TestToBoolNode": TestToBoolNode,
+    "TestBoolOperationNode": TestBoolOperationNode,
+}
+
+CONDITION_NODE_DISPLAY_NAME_MAPPINGS = {
+    "TestIntConditions": "Int Condition",
+    "TestFloatConditions": "Float Condition",
+    "TestStringConditions": "String Condition",
+    "TestToBoolNode": "To Bool",
+    "TestBoolOperationNode": "Bool Operation",
+}

tests/inference/testing_nodes/testing-pack/flow_control.py

@@ -0,0 +1,173 @@
+from comfy.graph_utils import GraphBuilder, is_link
+from comfy.graph import ExecutionBlocker
+from .tools import VariantSupport
+
+NUM_FLOW_SOCKETS = 5
+@VariantSupport()
+class TestWhileLoopOpen:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        inputs = {
+            "required": {
+                "condition": ("BOOLEAN", {"default": True}),
+            },
+            "optional": {
+            },
+        }
+        for i in range(NUM_FLOW_SOCKETS):
+            inputs["optional"][f"initial_value{i}"] = ("*",)
+        return inputs
+
+    RETURN_TYPES = tuple(["FLOW_CONTROL"] + ["*"] * NUM_FLOW_SOCKETS)
+    RETURN_NAMES = tuple(["FLOW_CONTROL"] + [f"value{i}" for i in range(NUM_FLOW_SOCKETS)])
+    FUNCTION = "while_loop_open"
+
+    CATEGORY = "Testing/Flow"
+
+    def while_loop_open(self, condition, **kwargs):
+        values = []
+        for i in range(NUM_FLOW_SOCKETS):
+            values.append(kwargs.get(f"initial_value{i}", None))
+        return tuple(["stub"] + values)
+
+@VariantSupport()
+class TestWhileLoopClose:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        inputs = {
+            "required": {
+                "flow_control": ("FLOW_CONTROL", {"rawLink": True}),
+                "condition": ("BOOLEAN", {"forceInput": True}),
+            },
+            "optional": {
+            },
+            "hidden": {
+                "dynprompt": "DYNPROMPT",
+                "unique_id": "UNIQUE_ID",
+            }
+        }
+        for i in range(NUM_FLOW_SOCKETS):
+            inputs["optional"][f"initial_value{i}"] = ("*",)
+        return inputs
+
+    RETURN_TYPES = tuple(["*"] * NUM_FLOW_SOCKETS)
+    RETURN_NAMES = tuple([f"value{i}" for i in range(NUM_FLOW_SOCKETS)])
+    FUNCTION = "while_loop_close"
+
+    CATEGORY = "Testing/Flow"
+
+    def explore_dependencies(self, node_id, dynprompt, upstream):
+        node_info = dynprompt.get_node(node_id)
+        if "inputs" not in node_info:
+            return
+        for k, v in node_info["inputs"].items():
+            if is_link(v):
+                parent_id = v[0]
+                if parent_id not in upstream:
+                    upstream[parent_id] = []
+                    self.explore_dependencies(parent_id, dynprompt, upstream)
+                upstream[parent_id].append(node_id)
+
+    def collect_contained(self, node_id, upstream, contained):
+        if node_id not in upstream:
+            return
+        for child_id in upstream[node_id]:
+            if child_id not in contained:
+                contained[child_id] = True
+                self.collect_contained(child_id, upstream, contained)
+
+
+    def while_loop_close(self, flow_control, condition, dynprompt=None, unique_id=None, **kwargs):
+        assert dynprompt is not None
+        if not condition:
+            # We're done with the loop
+            values = []
+            for i in range(NUM_FLOW_SOCKETS):
+                values.append(kwargs.get(f"initial_value{i}", None))
+            return tuple(values)
+
+        # We want to loop
+        upstream = {}
+        # Get the list of all nodes between the open and close nodes
+        self.explore_dependencies(unique_id, dynprompt, upstream)
+
+        contained = {}
+        open_node = flow_control[0]
+        self.collect_contained(open_node, upstream, contained)
+        contained[unique_id] = True
+        contained[open_node] = True
+
+        # We'll use the default prefix, but to avoid having node names grow exponentially in size,
+        # we'll use "Recurse" for the name of the recursively-generated copy of this node.
+        graph = GraphBuilder()
+        for node_id in contained:
+            original_node = dynprompt.get_node(node_id)
+            node = graph.node(original_node["class_type"], "Recurse" if node_id == unique_id else node_id)
+            node.set_override_display_id(node_id)
+        for node_id in contained:
+            original_node = dynprompt.get_node(node_id)
+            node = graph.lookup_node("Recurse" if node_id == unique_id else node_id)
+            assert node is not None
+            for k, v in original_node["inputs"].items():
+                if is_link(v) and v[0] in contained:
+                    parent = graph.lookup_node(v[0])
+                    assert parent is not None
+                    node.set_input(k, parent.out(v[1]))
+                else:
+                    node.set_input(k, v)
+        new_open = graph.lookup_node(open_node)
+        assert new_open is not None
+        for i in range(NUM_FLOW_SOCKETS):
+            key = f"initial_value{i}"
+            new_open.set_input(key, kwargs.get(key, None))
+        my_clone = graph.lookup_node("Recurse")
+        assert my_clone is not None
+        result = map(lambda x: my_clone.out(x), range(NUM_FLOW_SOCKETS))
+        return {
+            "result": tuple(result),
+            "expand": graph.finalize(),
+        }
+
+@VariantSupport()
+class TestExecutionBlockerNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        inputs = {
+            "required": {
+                "input": ("*",),
+                "block": ("BOOLEAN",),
+                "verbose": ("BOOLEAN", {"default": False}),
+            },
+        }
+        return inputs
+
+    RETURN_TYPES = ("*",)
+    RETURN_NAMES = ("output",)
+    FUNCTION = "execution_blocker"
+
+    CATEGORY = "Testing/Flow"
+
+    def execution_blocker(self, input, block, verbose):
+        if block:
+            return (ExecutionBlocker("Blocked Execution" if verbose else None),)
+        return (input,)
+
+FLOW_CONTROL_NODE_CLASS_MAPPINGS = {
+    "TestWhileLoopOpen": TestWhileLoopOpen,
+    "TestWhileLoopClose": TestWhileLoopClose,
+    "TestExecutionBlocker": TestExecutionBlockerNode,
+}
+FLOW_CONTROL_NODE_DISPLAY_NAME_MAPPINGS = {
+    "TestWhileLoopOpen": "While Loop Open",
+    "TestWhileLoopClose": "While Loop Close",
+    "TestExecutionBlocker": "Execution Blocker",
+}

tests/inference/testing_nodes/testing-pack/specific_tests.py

@@ -0,0 +1,335 @@
+import torch
+from .tools import VariantSupport
+from comfy.graph_utils import GraphBuilder
+
+class TestLazyMixImages:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "image1": ("IMAGE",{"lazy": True}),
+                "image2": ("IMAGE",{"lazy": True}),
+                "mask": ("MASK",),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "mix"
+
+    CATEGORY = "Testing/Nodes"
+
+    def check_lazy_status(self, mask, image1, image2):
+        mask_min = mask.min()
+        mask_max = mask.max()
+        needed = []
+        if image1 is None and (mask_min != 1.0 or mask_max != 1.0):
+            needed.append("image1")
+        if image2 is None and (mask_min != 0.0 or mask_max != 0.0):
+            needed.append("image2")
+        return needed
+
+    # Not trying to handle different batch sizes here just to keep the demo simple
+    def mix(self, mask, image1, image2):
+        mask_min = mask.min()
+        mask_max = mask.max()
+        if mask_min == 0.0 and mask_max == 0.0:
+            return (image1,)
+        elif mask_min == 1.0 and mask_max == 1.0:
+            return (image2,)
+
+        if len(mask.shape) == 2:
+            mask = mask.unsqueeze(0)
+        if len(mask.shape) == 3:
+            mask = mask.unsqueeze(3)
+        if mask.shape[3] < image1.shape[3]:
+            mask = mask.repeat(1, 1, 1, image1.shape[3])
+
+        result = image1 * (1. - mask) + image2 * mask,
+        return (result[0],)
+
+class TestVariadicAverage:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "input1": ("IMAGE",),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "variadic_average"
+
+    CATEGORY = "Testing/Nodes"
+
+    def variadic_average(self, input1, **kwargs):
+        inputs = [input1]
+        while 'input' + str(len(inputs) + 1) in kwargs:
+            inputs.append(kwargs['input' + str(len(inputs) + 1)])
+        return (torch.stack(inputs).mean(dim=0),)
+
+
+class TestCustomIsChanged:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "image": ("IMAGE",),
+            },
+            "optional": {
+                "should_change": ("BOOL", {"default": False}),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "custom_is_changed"
+
+    CATEGORY = "Testing/Nodes"
+
+    def custom_is_changed(self, image, should_change=False):
+        return (image,)
+    
+    @classmethod
+    def IS_CHANGED(cls, should_change=False, *args, **kwargs):
+        if should_change:
+            return float("NaN")
+        else:
+            return False
+
+class TestCustomValidation1:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "input1": ("IMAGE,FLOAT",),
+                "input2": ("IMAGE,FLOAT",),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "custom_validation1"
+
+    CATEGORY = "Testing/Nodes"
+
+    def custom_validation1(self, input1, input2):
+        if isinstance(input1, float) and isinstance(input2, float):
+            result = torch.ones([1, 512, 512, 3]) * input1 * input2
+        else:
+            result = input1 * input2
+        return (result,)
+
+    @classmethod
+    def VALIDATE_INPUTS(cls, input1=None, input2=None):
+        if input1 is not None:
+            if not isinstance(input1, (torch.Tensor, float)):
+                return f"Invalid type of input1: {type(input1)}"
+        if input2 is not None:
+            if not isinstance(input2, (torch.Tensor, float)):
+                return f"Invalid type of input2: {type(input2)}"
+
+        return True
+
+class TestCustomValidation2:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "input1": ("IMAGE,FLOAT",),
+                "input2": ("IMAGE,FLOAT",),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "custom_validation2"
+
+    CATEGORY = "Testing/Nodes"
+
+    def custom_validation2(self, input1, input2):
+        if isinstance(input1, float) and isinstance(input2, float):
+            result = torch.ones([1, 512, 512, 3]) * input1 * input2
+        else:
+            result = input1 * input2
+        return (result,)
+
+    @classmethod
+    def VALIDATE_INPUTS(cls, input_types, input1=None, input2=None):
+        if input1 is not None:
+            if not isinstance(input1, (torch.Tensor, float)):
+                return f"Invalid type of input1: {type(input1)}"
+        if input2 is not None:
+            if not isinstance(input2, (torch.Tensor, float)):
+                return f"Invalid type of input2: {type(input2)}"
+
+        if 'input1' in input_types:
+            if input_types['input1'] not in ["IMAGE", "FLOAT"]:
+                return f"Invalid type of input1: {input_types['input1']}"
+        if 'input2' in input_types:
+            if input_types['input2'] not in ["IMAGE", "FLOAT"]:
+                return f"Invalid type of input2: {input_types['input2']}"
+
+        return True
+
+@VariantSupport()
+class TestCustomValidation3:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "input1": ("IMAGE,FLOAT",),
+                "input2": ("IMAGE,FLOAT",),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "custom_validation3"
+
+    CATEGORY = "Testing/Nodes"
+
+    def custom_validation3(self, input1, input2):
+        if isinstance(input1, float) and isinstance(input2, float):
+            result = torch.ones([1, 512, 512, 3]) * input1 * input2
+        else:
+            result = input1 * input2
+        return (result,)
+
+class TestCustomValidation4:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "input1": ("FLOAT",),
+                "input2": ("FLOAT",),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "custom_validation4"
+
+    CATEGORY = "Testing/Nodes"
+
+    def custom_validation4(self, input1, input2):
+        result = torch.ones([1, 512, 512, 3]) * input1 * input2
+        return (result,)
+
+    @classmethod
+    def VALIDATE_INPUTS(cls, input1, input2):
+        if input1 is not None:
+            if not isinstance(input1, float):
+                return f"Invalid type of input1: {type(input1)}"
+        if input2 is not None:
+            if not isinstance(input2, float):
+                return f"Invalid type of input2: {type(input2)}"
+
+        return True
+
+class TestCustomValidation5:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "input1": ("FLOAT", {"min": 0.0, "max": 1.0}),
+                "input2": ("FLOAT", {"min": 0.0, "max": 1.0}),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "custom_validation5"
+
+    CATEGORY = "Testing/Nodes"
+
+    def custom_validation5(self, input1, input2):
+        value = input1 * input2
+        return (torch.ones([1, 512, 512, 3]) * value,)
+
+    @classmethod
+    def VALIDATE_INPUTS(cls, **kwargs):
+        if kwargs['input2'] == 7.0:
+            return "7s are not allowed. I've never liked 7s."
+        return True
+
+class TestDynamicDependencyCycle:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "input1": ("IMAGE",),
+                "input2": ("IMAGE",),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "dynamic_dependency_cycle"
+
+    CATEGORY = "Testing/Nodes"
+
+    def dynamic_dependency_cycle(self, input1, input2):
+        g = GraphBuilder()
+        mask = g.node("StubMask", value=0.5, height=512, width=512, batch_size=1)
+        mix1 = g.node("TestLazyMixImages", image1=input1, mask=mask.out(0))
+        mix2 = g.node("TestLazyMixImages", image1=mix1.out(0), image2=input2, mask=mask.out(0))
+
+        # Create the cyle
+        mix1.set_input("image2", mix2.out(0))
+
+        return {
+            "result": (mix2.out(0),),
+            "expand": g.finalize(),
+        }
+
+class TestMixedExpansionReturns:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "input1": ("FLOAT",),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE","IMAGE")
+    FUNCTION = "mixed_expansion_returns"
+
+    CATEGORY = "Testing/Nodes"
+
+    def mixed_expansion_returns(self, input1):
+        white_image = torch.ones([1, 512, 512, 3])
+        if input1 <= 0.1:
+            return (torch.ones([1, 512, 512, 3]) * 0.1, white_image)
+        elif input1 <= 0.2:
+            return {
+                "result": (torch.ones([1, 512, 512, 3]) * 0.2, white_image),
+            }
+        else:
+            g = GraphBuilder()
+            mask = g.node("StubMask", value=0.3, height=512, width=512, batch_size=1)
+            black = g.node("StubImage", content="BLACK", height=512, width=512, batch_size=1)
+            white = g.node("StubImage", content="WHITE", height=512, width=512, batch_size=1)
+            mix = g.node("TestLazyMixImages", image1=black.out(0), image2=white.out(0), mask=mask.out(0))
+            return {
+                "result": (mix.out(0), white_image),
+                "expand": g.finalize(),
+            }
+
+TEST_NODE_CLASS_MAPPINGS = {
+    "TestLazyMixImages": TestLazyMixImages,
+    "TestVariadicAverage": TestVariadicAverage,
+    "TestCustomIsChanged": TestCustomIsChanged,
+    "TestCustomValidation1": TestCustomValidation1,
+    "TestCustomValidation2": TestCustomValidation2,
+    "TestCustomValidation3": TestCustomValidation3,
+    "TestCustomValidation4": TestCustomValidation4,
+    "TestCustomValidation5": TestCustomValidation5,
+    "TestDynamicDependencyCycle": TestDynamicDependencyCycle,
+    "TestMixedExpansionReturns": TestMixedExpansionReturns,
+}
+
+TEST_NODE_DISPLAY_NAME_MAPPINGS = {
+    "TestLazyMixImages": "Lazy Mix Images",
+    "TestVariadicAverage": "Variadic Average",
+    "TestCustomIsChanged": "Custom IsChanged",
+    "TestCustomValidation1": "Custom Validation 1",
+    "TestCustomValidation2": "Custom Validation 2",
+    "TestCustomValidation3": "Custom Validation 3",
+    "TestCustomValidation4": "Custom Validation 4",
+    "TestCustomValidation5": "Custom Validation 5",
+    "TestDynamicDependencyCycle": "Dynamic Dependency Cycle",
+    "TestMixedExpansionReturns": "Mixed Expansion Returns",
+}

tests/inference/testing_nodes/testing-pack/stubs.py

@@ -0,0 +1,105 @@
+import torch
+
+class StubImage:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "content": (['WHITE', 'BLACK', 'NOISE'],),
+                "height": ("INT", {"default": 512, "min": 1, "max": 1024 ** 3, "step": 1}),
+                "width": ("INT", {"default": 512, "min": 1, "max": 4096 ** 3, "step": 1}),
+                "batch_size": ("INT", {"default": 1, "min": 1, "max": 1024 ** 3, "step": 1}),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "stub_image"
+
+    CATEGORY = "Testing/Stub Nodes"
+
+    def stub_image(self, content, height, width, batch_size):
+        if content == "WHITE":
+            return (torch.ones(batch_size, height, width, 3),)
+        elif content == "BLACK":
+            return (torch.zeros(batch_size, height, width, 3),)
+        elif content == "NOISE":
+            return (torch.rand(batch_size, height, width, 3),)
+
+class StubMask:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "value": ("FLOAT", {"default": 0.5, "min": 0.0, "max": 1.0, "step": 0.01}),
+                "height": ("INT", {"default": 512, "min": 1, "max": 1024 ** 3, "step": 1}),
+                "width": ("INT", {"default": 512, "min": 1, "max": 4096 ** 3, "step": 1}),
+                "batch_size": ("INT", {"default": 1, "min": 1, "max": 1024 ** 3, "step": 1}),
+            },
+        }
+
+    RETURN_TYPES = ("MASK",)
+    FUNCTION = "stub_mask"
+
+    CATEGORY = "Testing/Stub Nodes"
+
+    def stub_mask(self, value, height, width, batch_size):
+        return (torch.ones(batch_size, height, width) * value,)
+
+class StubInt:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "value": ("INT", {"default": 0, "min": -0xffffffff, "max": 0xffffffff, "step": 1}),
+            },
+        }
+
+    RETURN_TYPES = ("INT",)
+    FUNCTION = "stub_int"
+
+    CATEGORY = "Testing/Stub Nodes"
+
+    def stub_int(self, value):
+        return (value,)
+
+class StubFloat:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "value": ("FLOAT", {"default": 0.0, "min": -1.0e38, "max": 1.0e38, "step": 0.01}),
+            },
+        }
+
+    RETURN_TYPES = ("FLOAT",)
+    FUNCTION = "stub_float"
+
+    CATEGORY = "Testing/Stub Nodes"
+
+    def stub_float(self, value):
+        return (value,)
+
+TEST_STUB_NODE_CLASS_MAPPINGS = {
+    "StubImage": StubImage,
+    "StubMask": StubMask,
+    "StubInt": StubInt,
+    "StubFloat": StubFloat,
+}
+TEST_STUB_NODE_DISPLAY_NAME_MAPPINGS = {
+    "StubImage": "Stub Image",
+    "StubMask": "Stub Mask",
+    "StubInt": "Stub Int",
+    "StubFloat": "Stub Float",
+}

tests/inference/testing_nodes/testing-pack/tools.py

@@ -0,0 +1,53 @@
+
+def MakeSmartType(t):
+    if isinstance(t, str):
+        return SmartType(t)
+    return t
+
+class SmartType(str):
+    def __ne__(self, other):
+        if self == "*" or other == "*":
+            return False
+        selfset = set(self.split(','))
+        otherset = set(other.split(','))
+        return not selfset.issubset(otherset)
+
+def VariantSupport():
+    def decorator(cls):
+        if hasattr(cls, "INPUT_TYPES"):
+            old_input_types = getattr(cls, "INPUT_TYPES")
+            def new_input_types(*args, **kwargs):
+                types = old_input_types(*args, **kwargs)
+                for category in ["required", "optional"]:
+                    if category not in types:
+                        continue
+                    for key, value in types[category].items():
+                        if isinstance(value, tuple):
+                            types[category][key] = (MakeSmartType(value[0]),) + value[1:]
+                return types
+            setattr(cls, "INPUT_TYPES", new_input_types)
+        if hasattr(cls, "RETURN_TYPES"):
+            old_return_types = cls.RETURN_TYPES
+            setattr(cls, "RETURN_TYPES", tuple(MakeSmartType(x) for x in old_return_types))
+        if hasattr(cls, "VALIDATE_INPUTS"):
+            # Reflection is used to determine what the function signature is, so we can't just change the function signature
+            raise NotImplementedError("VariantSupport does not support VALIDATE_INPUTS yet")
+        else:
+            def validate_inputs(input_types):
+                inputs = cls.INPUT_TYPES()
+                for key, value in input_types.items():
+                    if isinstance(value, SmartType):
+                        continue
+                    if "required" in inputs and key in inputs["required"]:
+                        expected_type = inputs["required"][key][0]
+                    elif "optional" in inputs and key in inputs["optional"]:
+                        expected_type = inputs["optional"][key][0]
+                    else:
+                        expected_type = None
+                    if expected_type is not None and MakeSmartType(value) != expected_type:
+                        return f"Invalid type of {key}: {value} (expected {expected_type})"
+                return True
+            setattr(cls, "VALIDATE_INPUTS", validate_inputs)
+        return cls
+    return decorator
+

tests/inference/testing_nodes/testing-pack/util.py

@@ -0,0 +1,364 @@
+from comfy.graph_utils import GraphBuilder
+from .tools import VariantSupport
+
+@VariantSupport()
+class TestAccumulateNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "to_add": ("*",),
+            },
+            "optional": {
+                "accumulation": ("ACCUMULATION",),
+            },
+        }
+
+    RETURN_TYPES = ("ACCUMULATION",)
+    FUNCTION = "accumulate"
+
+    CATEGORY = "Testing/Lists"
+
+    def accumulate(self, to_add, accumulation = None):
+        if accumulation is None:
+            value = [to_add]
+        else:
+            value = accumulation["accum"] + [to_add]
+        return ({"accum": value},)
+
+@VariantSupport()
+class TestAccumulationHeadNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "accumulation": ("ACCUMULATION",),
+            },
+        }
+
+    RETURN_TYPES = ("ACCUMULATION", "*",)
+    FUNCTION = "accumulation_head"
+
+    CATEGORY = "Testing/Lists"
+
+    def accumulation_head(self, accumulation):
+        accum = accumulation["accum"]
+        if len(accum) == 0:
+            return (accumulation, None)
+        else:
+            return ({"accum": accum[1:]}, accum[0])
+
+class TestAccumulationTailNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "accumulation": ("ACCUMULATION",),
+            },
+        }
+
+    RETURN_TYPES = ("ACCUMULATION", "*",)
+    FUNCTION = "accumulation_tail"
+
+    CATEGORY = "Testing/Lists"
+
+    def accumulation_tail(self, accumulation):
+        accum = accumulation["accum"]
+        if len(accum) == 0:
+            return (None, accumulation)
+        else:
+            return ({"accum": accum[:-1]}, accum[-1])
+
+@VariantSupport()
+class TestAccumulationToListNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "accumulation": ("ACCUMULATION",),
+            },
+        }
+
+    RETURN_TYPES = ("*",)
+    OUTPUT_IS_LIST = (True,)
+
+    FUNCTION = "accumulation_to_list"
+
+    CATEGORY = "Testing/Lists"
+
+    def accumulation_to_list(self, accumulation):
+        return (accumulation["accum"],)
+
+@VariantSupport()
+class TestListToAccumulationNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "list": ("*",),
+            },
+        }
+
+    RETURN_TYPES = ("ACCUMULATION",)
+    INPUT_IS_LIST = (True,)
+
+    FUNCTION = "list_to_accumulation"
+
+    CATEGORY = "Testing/Lists"
+
+    def list_to_accumulation(self, list):
+        return ({"accum": list},)
+
+@VariantSupport()
+class TestAccumulationGetLengthNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "accumulation": ("ACCUMULATION",),
+            },
+        }
+
+    RETURN_TYPES = ("INT",)
+
+    FUNCTION = "accumlength"
+
+    CATEGORY = "Testing/Lists"
+
+    def accumlength(self, accumulation):
+        return (len(accumulation['accum']),)
+        
+@VariantSupport()
+class TestAccumulationGetItemNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "accumulation": ("ACCUMULATION",),
+                "index": ("INT", {"default":0, "step":1})
+            },
+        }
+
+    RETURN_TYPES = ("*",)
+
+    FUNCTION = "get_item"
+
+    CATEGORY = "Testing/Lists"
+
+    def get_item(self, accumulation, index):
+        return (accumulation['accum'][index],)
+        
+@VariantSupport()
+class TestAccumulationSetItemNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "accumulation": ("ACCUMULATION",),
+                "index": ("INT", {"default":0, "step":1}),
+                "value": ("*",),
+            },
+        }
+
+    RETURN_TYPES = ("ACCUMULATION",)
+
+    FUNCTION = "set_item"
+
+    CATEGORY = "Testing/Lists"
+
+    def set_item(self, accumulation, index, value):
+        new_accum = accumulation['accum'][:]
+        new_accum[index] = value
+        return ({"accum": new_accum},)
+
+class TestIntMathOperation:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "a": ("INT", {"default": 0, "min": -0xffffffffffffffff, "max": 0xffffffffffffffff, "step": 1}),
+                "b": ("INT", {"default": 0, "min": -0xffffffffffffffff, "max": 0xffffffffffffffff, "step": 1}),
+                "operation": (["add", "subtract", "multiply", "divide", "modulo", "power"],),
+            },
+        }
+
+    RETURN_TYPES = ("INT",)
+    FUNCTION = "int_math_operation"
+
+    CATEGORY = "Testing/Logic"
+
+    def int_math_operation(self, a, b, operation):
+        if operation == "add":
+            return (a + b,)
+        elif operation == "subtract":
+            return (a - b,)
+        elif operation == "multiply":
+            return (a * b,)
+        elif operation == "divide":
+            return (a // b,)
+        elif operation == "modulo":
+            return (a % b,)
+        elif operation == "power":
+            return (a ** b,)
+
+
+from .flow_control import NUM_FLOW_SOCKETS
+@VariantSupport()
+class TestForLoopOpen:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "remaining": ("INT", {"default": 1, "min": 0, "max": 100000, "step": 1}),
+            },
+            "optional": {
+                f"initial_value{i}": ("*",) for i in range(1, NUM_FLOW_SOCKETS)
+            },
+            "hidden": {
+                "initial_value0": ("*",)
+            }
+        }
+
+    RETURN_TYPES = tuple(["FLOW_CONTROL", "INT",] + ["*"] * (NUM_FLOW_SOCKETS-1))
+    RETURN_NAMES = tuple(["flow_control", "remaining"] + [f"value{i}" for i in range(1, NUM_FLOW_SOCKETS)])
+    FUNCTION = "for_loop_open"
+
+    CATEGORY = "Testing/Flow"
+
+    def for_loop_open(self, remaining, **kwargs):
+        graph = GraphBuilder()
+        if "initial_value0" in kwargs:
+            remaining = kwargs["initial_value0"]
+        while_open = graph.node("TestWhileLoopOpen", condition=remaining, initial_value0=remaining, **{(f"initial_value{i}"): kwargs.get(f"initial_value{i}", None) for i in range(1, NUM_FLOW_SOCKETS)})
+        outputs = [kwargs.get(f"initial_value{i}", None) for i in range(1, NUM_FLOW_SOCKETS)]
+        return {
+            "result": tuple(["stub", remaining] + outputs),
+            "expand": graph.finalize(),
+        }
+
+@VariantSupport()
+class TestForLoopClose:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "flow_control": ("FLOW_CONTROL", {"rawLink": True}),
+            },
+            "optional": {
+                f"initial_value{i}": ("*",{"rawLink": True}) for i in range(1, NUM_FLOW_SOCKETS)
+            },
+        }
+
+    RETURN_TYPES = tuple(["*"] * (NUM_FLOW_SOCKETS-1))
+    RETURN_NAMES = tuple([f"value{i}" for i in range(1, NUM_FLOW_SOCKETS)])
+    FUNCTION = "for_loop_close"
+
+    CATEGORY = "Testing/Flow"
+
+    def for_loop_close(self, flow_control, **kwargs):
+        graph = GraphBuilder()
+        while_open = flow_control[0]
+        sub = graph.node("TestIntMathOperation", operation="subtract", a=[while_open,1], b=1)
+        cond = graph.node("TestToBoolNode", value=sub.out(0))
+        input_values = {f"initial_value{i}": kwargs.get(f"initial_value{i}", None) for i in range(1, NUM_FLOW_SOCKETS)}
+        while_close = graph.node("TestWhileLoopClose",
+                flow_control=flow_control,
+                condition=cond.out(0),
+                initial_value0=sub.out(0),
+                **input_values)
+        return {
+            "result": tuple([while_close.out(i) for i in range(1, NUM_FLOW_SOCKETS)]),
+            "expand": graph.finalize(),
+        }
+
+NUM_LIST_SOCKETS = 10
+@VariantSupport()
+class TestMakeListNode:
+    def __init__(self):
+        pass
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "value1": ("*",),
+            },
+            "optional": {
+                f"value{i}": ("*",) for i in range(1, NUM_LIST_SOCKETS)
+            },
+        }
+
+    RETURN_TYPES = ("*",)
+    FUNCTION = "make_list"
+    OUTPUT_IS_LIST = (True,)
+
+    CATEGORY = "Testing/Lists"
+
+    def make_list(self, **kwargs):
+        result = []
+        for i in range(NUM_LIST_SOCKETS):
+            if f"value{i}" in kwargs:
+                result.append(kwargs[f"value{i}"])
+        return (result,)
+
+UTILITY_NODE_CLASS_MAPPINGS = {
+    "TestAccumulateNode": TestAccumulateNode,
+    "TestAccumulationHeadNode": TestAccumulationHeadNode,
+    "TestAccumulationTailNode": TestAccumulationTailNode,
+    "TestAccumulationToListNode": TestAccumulationToListNode,
+    "TestListToAccumulationNode": TestListToAccumulationNode,
+    "TestAccumulationGetLengthNode": TestAccumulationGetLengthNode,
+    "TestAccumulationGetItemNode": TestAccumulationGetItemNode,
+    "TestAccumulationSetItemNode": TestAccumulationSetItemNode,
+    "TestForLoopOpen": TestForLoopOpen,
+    "TestForLoopClose": TestForLoopClose,
+    "TestIntMathOperation": TestIntMathOperation,
+    "TestMakeListNode": TestMakeListNode,
+}
+UTILITY_NODE_DISPLAY_NAME_MAPPINGS = {
+    "TestAccumulateNode": "Accumulate",
+    "TestAccumulationHeadNode": "Accumulation Head",
+    "TestAccumulationTailNode": "Accumulation Tail",
+    "TestAccumulationToListNode": "Accumulation to List",
+    "TestListToAccumulationNode": "List to Accumulation",
+    "TestAccumulationGetLengthNode": "Accumulation Get Length",
+    "TestAccumulationGetItemNode": "Accumulation Get Item",
+    "TestAccumulationSetItemNode": "Accumulation Set Item",
+    "TestForLoopOpen": "For Loop Open",
+    "TestForLoopClose": "For Loop Close",
+    "TestIntMathOperation": "Int Math Operation",
+    "TestMakeListNode": "Make List",
+}