DynamicOutputs: replace FromInput with BySlot; outputs always declared in Schema.outputs

ByKey already covered literal-driven dispatch (Combo/DynamicCombo/String);
add BySlot as the symmetric resolved-type-driven form (mirrors DynamicSlot).

Inputs no longer carry output declarations. DynamicCombo.Option / DynamicSlot.Option
go back to {key|when, inputs} only — outputs always live on the corresponding
DynamicOutputs entry in Schema.outputs. Validation enforces that ByKey option keys
align with the referenced DynamicCombo's keys and BySlot option 'when' types are a
subset of the referenced DynamicSlot's accepted types (including when=None).

Removes FromInput/_select_from_input_outputs/_from_input_as_dict and the
option-level output serialization helpers.

Amp-Thread-ID: https://ampcode.com/threads/T-019e8568-f382-743d-a97f-0de3ff29d501
Co-authored-by: Amp <amp@ampcode.com>

comfy_api/latest/_io.py

@@ -1141,46 +1141,20 @@ class Autogrow(ComfyTypeI):
             out_dict["dynamic_paths_default_value"][finalized_prefix] = DynamicPathsDefaultValue.EMPTY_DICT
         parse_class_inputs(out_dict, live_inputs, new_dict, curr_prefix, live_input_types)
 
-def _validate_option_outputs(label: str, outputs: list[Output] | None) -> list[Output]:
-    """Validate option outputs once at construction; return [] for missing/empty."""
-    if outputs is None:
-        return []
-    for o in outputs:
-        if not isinstance(o, Output):
-            raise ValueError(f"{label}: outputs must contain Output instances, got {o!r}")
-        if o.id is None:
-            raise ValueError(f"{label}: every output must declare an id")
-    return outputs
-
-
-def _serialize_option_outputs(outputs: list[Output]) -> list[dict] | None:
-    """Inline-serialize option outputs for V1 info; None drops the field via prune_dict."""
-    if not outputs:
-        return None
-    return [
-        {"id": o.id, "type": o.get_io_type(), **o.as_dict()}
-        for o in outputs
-    ]
-
-
 @comfytype(io_type="COMFY_DYNAMICCOMBO_V3")
 class DynamicCombo(ComfyTypeI):
     Type = dict[str, Any]
 
     class Option:
-        def __init__(self, key: str, inputs: list[Input], outputs: list[Output] | None = None):
+        def __init__(self, key: str, inputs: list[Input]):
             self.key = key
             self.inputs = inputs
-            # When this DynamicCombo input is referenced by DynamicOutputs.FromInput,
-            # the active option's ``outputs`` are spliced into the finalized list.
-            self.outputs = _validate_option_outputs("DynamicCombo.Option", outputs)
 
         def as_dict(self):
-            return prune_dict({
+            return {
                 "key": self.key,
                 "inputs": create_input_dict_v1(self.inputs),
-                "outputs": _serialize_option_outputs(self.outputs),
-            })
+            }
 
     class Input(DynamicInput):
         def __init__(self, id: str, options: list[DynamicCombo.Option],
@@ -1250,12 +1224,9 @@ class DynamicSlot(ComfyTypeI):
           * a list of ComfyType classes (shared branch across multiple types)
           * a ``MultiType.Input`` instance (parsed via its ``.io_types``)
         """
-        def __init__(self, when: Any, inputs: list[Input] = None, outputs: list[Output] | None = None):
+        def __init__(self, when: Any, inputs: list[Input] = None):
             self.when = when
             self.inputs = inputs or []
-            # When this DynamicSlot input is referenced by DynamicOutputs.FromInput,
-            # the active option's ``outputs`` are spliced into the finalized list.
-            self.outputs = _validate_option_outputs("DynamicSlot.Option", outputs)
             # ``_when_types`` is the ordered tuple of io_types (deterministic);
             # ``_when_set`` is the same content as a set for fast matching.
             self._when_types = self._normalize_when(when)
@@ -1301,16 +1272,10 @@ class DynamicSlot(ComfyTypeI):
             )
 
         def as_dict(self):
-            # ``when`` is preserved even when None (meaningful "unconnected" branch);
-            # ``outputs`` is pruned when absent so existing serializations don't drift.
-            d = {
+            return {
                 "when": None if self._when_types is None else list(self._when_types),
                 "inputs": create_input_dict_v1(self.inputs),
             }
-            outs = _serialize_option_outputs(self.outputs)
-            if outs is not None:
-                d["outputs"] = outs
-            return d
 
     class Input(DynamicInput):
         def __init__(self, id: str, options: list[DynamicSlot.Option],
@@ -1455,48 +1420,56 @@ class DynamicOutputs:
 
     Forms:
 
-      * :py:class:`DynamicOutputs.ByKey` — outputs are declared inline on the
-        group and picked by the literal value of a same-node selector input.
-      * :py:class:`DynamicOutputs.FromInput` — positional placeholder that
-        reuses the per-option ``outputs=[…]`` declared on a
-        :py:class:`DynamicCombo.Input` or :py:class:`DynamicSlot.Input`,
-        keeping the option content single-sourced.
+      * :py:class:`DynamicOutputs.ByKey` — selector is a literal input
+        (``Combo`` / ``DynamicCombo`` / ``String`` / etc.) and the active
+        option is chosen by direct value comparison against ``Option.key``.
+      * :py:class:`DynamicOutputs.BySlot` — selector is a
+        :py:class:`DynamicSlot.Input` and the active option is chosen by
+        the slot's resolved upstream type, matching ``Option.when``.
 
     Inactive options do not produce placeholder slots — downstream links to
     nonexistent finalized slots are rejected by validation.
     """
 
     class Option:
-        """One branch of outputs revealed when the selector matches ``key``."""
+        """A branch of outputs for :py:class:`DynamicOutputs.ByKey`."""
 
         def __init__(self, key: str, outputs: list[Output]):
             if not isinstance(key, str) or not key:
                 raise ValueError("DynamicOutputs.Option: key must be a non-empty string")
-            for o in outputs:
-                if not isinstance(o, Output):
-                    raise ValueError(
-                        f"DynamicOutputs.Option: outputs must contain Output instances, got {o!r}"
-                    )
-                if o.id is None:
-                    raise ValueError("DynamicOutputs.Option: every output must declare an id")
+            _validate_outputs("DynamicOutputs.Option", outputs)
             self.key = key
             self.outputs = outputs
 
+        def as_dict(self):
+            return {"key": self.key, "outputs": _serialize_outputs(self.outputs)}
+
+    class SlotOption:
+        """A branch of outputs for :py:class:`DynamicOutputs.BySlot`.
+
+        ``when`` accepts the same shapes as :py:class:`DynamicSlot.Option.when`
+        (``None``, ``io.AnyType``, a single ComfyType class, a list of classes,
+        or a ``MultiType.Input``); validation requires it to be a subset of the
+        target ``DynamicSlot.Input``'s declared types.
+        """
+
+        def __init__(self, when: Any, outputs: list[Output]):
+            _validate_outputs("DynamicOutputs.SlotOption", outputs)
+            self.when = when
+            self.outputs = outputs
+            self._when_types = DynamicSlot.Option._normalize_when(when)
+            self._when_set: frozenset[str] | None = (
+                None if self._when_types is None else frozenset(self._when_types)
+            )
+
         def as_dict(self):
             return {
-                "key": self.key,
-                "outputs": [
-                    {
-                        "id": o.id,
-                        "type": o.get_io_type(),
-                        **o.as_dict(),
-                    }
-                    for o in self.outputs
-                ],
+                "when": None if self._when_types is None else list(self._when_types),
+                "outputs": _serialize_outputs(self.outputs),
             }
 
     class ByKey:
-        """Active outputs are picked by the literal value of one of the node's inputs."""
+        """Active outputs picked by the literal value of a same-node input."""
 
         kind = "by_key"
 
@@ -1539,7 +1512,11 @@ class DynamicOutputs:
         def select(self, prompt_inputs: dict[str, Any]) -> DynamicOutputs.Option | None:
             """Pick the matching ``Option`` for the prompt's selector value, or ``None``."""
             value = prompt_inputs.get(self.selector)
-            # Links are ``[node_id, slot_idx]`` lists; for this slice we only accept literals.
+            # DynamicCombo wraps the literal in a nested dict {selector_id: {selector_id: key, ...}};
+            # unwrap so authors don't have to special-case it.
+            if isinstance(value, dict):
+                value = value.get(self.selector)
+            # Links are ``[node_id, slot_idx]`` lists; only literals finalize.
             if isinstance(value, list):
                 return None
             for opt in self.options:
@@ -1547,55 +1524,91 @@ class DynamicOutputs:
                     return opt
             return None
 
-    class FromInput:
-        """Positional placeholder that pulls outputs from a referenced dynamic input.
+    class BySlot:
+        """Active outputs picked by the resolved upstream type of a DynamicSlot input."""
 
-        Set ``input_id`` to the id of a :py:class:`DynamicCombo.Input` or
-        :py:class:`DynamicSlot.Input` on the same node. At finalization time
-        the active option of that input contributes its ``outputs=[…]`` here.
-        """
+        kind = "by_slot"
 
-        # ``kind`` is filled at finalize-time from the resolved source input
-        # ("by_key" for DynamicCombo, "by_slot" for DynamicSlot).
-        kind = "from_input"
+        def __init__(self, id: str, selector: str, options: list[DynamicOutputs.SlotOption]):
+            if not isinstance(id, str) or not id:
+                raise ValueError("DynamicOutputs.BySlot: id must be a non-empty string")
+            if not isinstance(selector, str) or not selector:
+                raise ValueError("DynamicOutputs.BySlot: selector must be a non-empty string input id")
+            if not options:
+                raise ValueError("DynamicOutputs.BySlot: at least one Option is required")
+            seen_types: set[str] = set()
+            seen_none = False
+            seen_ids: set[str] = set()
+            for opt in options:
+                if not isinstance(opt, DynamicOutputs.SlotOption):
+                    raise ValueError(
+                        f"DynamicOutputs.BySlot: options must be DynamicOutputs.SlotOption, got {opt!r}"
+                    )
+                if opt._when_types is None:
+                    if seen_none:
+                        raise ValueError("DynamicOutputs.BySlot: only one option may declare when=None")
+                    seen_none = True
+                else:
+                    for t in opt._when_types:
+                        if t in seen_types:
+                            raise ValueError(
+                                f"DynamicOutputs.BySlot: type {t!r} appears in more than one option; "
+                                "each type must be claimed by exactly one option"
+                            )
+                        seen_types.add(t)
+                for o in opt.outputs:
+                    if o.id in seen_ids:
+                        raise ValueError(
+                            f"DynamicOutputs.BySlot: output id {o.id!r} appears in more than one option; "
+                            "each output id must be unique within the group"
+                        )
+                    seen_ids.add(o.id)
+            self.id = id
+            self.selector = selector
+            self.options = options
 
-        def __init__(self, input_id: str):
-            if not isinstance(input_id, str) or not input_id:
-                raise ValueError("DynamicOutputs.FromInput: input_id must be a non-empty string")
-            self.input_id = input_id
-
-
-def _from_input_as_dict(placeholder: DynamicOutputs.FromInput, source) -> dict[str, Any]:
-    """Synthesize a ``dynamic_outputs`` entry for a ``FromInput`` placeholder.
-
-    Inlines the outputs of each option so the frontend can render output pins
-    without cross-referencing the input declaration. ``kind`` is ``"by_key"``
-    for DynamicCombo (literal-driven) or ``"by_slot"`` for DynamicSlot
-    (resolved-type-driven).
-    """
-    if isinstance(source, DynamicCombo.Input):
-        return {
-            "id": placeholder.input_id,
-            "kind": "by_key",
-            "selector": source.id,
-            "options": [
-                {"key": opt.key, "outputs": _serialize_option_outputs(opt.outputs) or []}
-                for opt in source.options
-            ],
-        }
-    # DynamicSlot.Input
-    return {
-        "id": placeholder.input_id,
-        "kind": "by_slot",
-        "selector": source.id,
-        "options": [
-            {
-                "when": None if opt._when_types is None else list(opt._when_types),
-                "outputs": _serialize_option_outputs(opt.outputs) or [],
+        def as_dict(self):
+            return {
+                "id": self.id,
+                "kind": self.kind,
+                "selector": self.selector,
+                "options": [opt.as_dict() for opt in self.options],
             }
-            for opt in source.options
-        ],
-    }
+
+        def select(self, prompt_inputs: dict[str, Any],
+                   live_input_types: dict[str, str] | None) -> DynamicOutputs.SlotOption | None:
+            """Pick the matching ``SlotOption`` for the slot's resolved type."""
+            raw = prompt_inputs.get(self.selector)
+            has_link = isinstance(raw, list) and raw is not None
+            if not has_link:
+                for opt in self.options:
+                    if opt._when_types is None:
+                        return opt
+                return None
+            resolved = (live_input_types or {}).get(self.selector, "*")
+            resolved_set = {t.strip() for t in resolved.split(",")}
+            for opt in self.options:
+                if opt._when_types is None:
+                    continue
+                if resolved_set & opt._when_set:
+                    return opt
+            return None
+
+
+def _validate_outputs(label: str, outputs: list[Output]) -> None:
+    """Sanity-check a list of outputs at option construction."""
+    if not outputs:
+        return
+    for o in outputs:
+        if not isinstance(o, Output):
+            raise ValueError(f"{label}: outputs must contain Output instances, got {o!r}")
+        if o.id is None:
+            raise ValueError(f"{label}: every output must declare an id")
+
+
+def _serialize_outputs(outputs: list[Output]) -> list[dict]:
+    """Inline-serialize outputs for V1 ``dynamic_outputs`` entries."""
+    return [{"id": o.id, "type": o.get_io_type(), **o.as_dict()} for o in outputs]
 
 
 def _output_metadata(o: Output) -> tuple[str, str, str, bool, str | None]:
@@ -1605,62 +1618,18 @@ def _output_metadata(o: Output) -> tuple[str, str, str, bool, str | None]:
     return o.id, rt, name, o.is_output_list, (o.tooltip if o.tooltip else None)
 
 
-def _select_from_input_outputs(
-    placeholder: DynamicOutputs.FromInput,
-    schema_inputs: list | None,
-    prompt_inputs: dict[str, Any],
-    live_input_types: dict[str, str] | None,
-) -> list[Output]:
-    """Return the active option's outputs for a ``FromInput`` placeholder."""
-    if not schema_inputs:
-        return []
-    source = next(
-        (i for i in schema_inputs
-         if isinstance(i, (DynamicCombo.Input, DynamicSlot.Input)) and i.id == placeholder.input_id),
-        None,
-    )
-    if source is None:
-        return []
-    if isinstance(source, DynamicCombo.Input):
-        value = prompt_inputs.get(source.id)
-        if isinstance(value, list):  # link, not a literal — no branch finalizable
-            return []
-        for opt in source.options:
-            if opt.key == value:
-                return opt.outputs
-        return []
-    # DynamicSlot: matched by resolved upstream type (or when=None when unlinked).
-    raw = prompt_inputs.get(source.id)
-    has_link = isinstance(raw, list) and raw is not None
-    if not has_link:
-        for opt in source.options:
-            if opt._when_types is None:
-                return opt.outputs
-        return []
-    resolved = (live_input_types or {}).get(source.id, "*")
-    resolved_set = {t.strip() for t in resolved.split(",")}
-    for opt in source.options:
-        if opt._when_types is None:
-            continue
-        if resolved_set & opt._when_set:
-            return opt.outputs
-    return []
-
-
 def get_finalized_class_outputs(
     schema_outputs: list,
     prompt_inputs: dict[str, Any] | None,
-    schema_inputs: list | None = None,
     live_input_types: dict[str, str] | None = None,
 ) -> FinalizedOutputs:
     """Resolve the active output list for a node.
 
     Expands :py:class:`DynamicOutputs.ByKey` against ``prompt_inputs`` and
-    :py:class:`DynamicOutputs.FromInput` against the matching
-    :py:class:`DynamicCombo.Input` / :py:class:`DynamicSlot.Input` (using
-    ``live_input_types`` for the slot case). Inactive options contribute
-    no slots — downstream links to nonexistent finalized slots are caught
-    by validation rather than silently filled with ``AnyType`` placeholders.
+    :py:class:`DynamicOutputs.BySlot` against ``live_input_types``. Inactive
+    options contribute no slots — downstream links to ranges that only existed
+    under a different branch are caught by validation rather than silently
+    filled with ``AnyType`` placeholders.
     """
     inputs = prompt_inputs or {}
     outputs: list[Output] = []
@@ -1687,9 +1656,11 @@ def get_finalized_class_outputs(
             if selected is not None:
                 for o in selected.outputs:
                     append_output(o)
-        elif isinstance(entry, DynamicOutputs.FromInput):
-            for o in _select_from_input_outputs(entry, schema_inputs, inputs, live_input_types):
-                append_output(o)
+        elif isinstance(entry, DynamicOutputs.BySlot):
+            selected = entry.select(inputs, live_input_types)
+            if selected is not None:
+                for o in selected.outputs:
+                    append_output(o)
         # else: ignore unknown entries (future-proofing for new dynamic kinds)
     return FinalizedOutputs(
         outputs=outputs,
@@ -2073,9 +2044,12 @@ class Schema:
 
     def validate(self):
         '''Validate the schema:
-        - verify ids on inputs and outputs are unique - both internally and in relation to each other
-        - verify dynamic-output groups reference real inputs and have unique active ids
-        - verify DynamicOutputs.FromInput placeholders reference real DynamicCombo / DynamicSlot inputs
+        - input/output ids are unique within and across each other
+        - DynamicOutputs.ByKey / BySlot have unique group ids
+        - ByKey selectors reference a real input (literal alignment validated when
+          the selector is a DynamicCombo)
+        - BySlot selectors reference a real DynamicSlot input and every option's
+          ``when`` is accepted by that slot
         '''
         nested_inputs: list[Input] = []
         for input in self.inputs:
@@ -2083,82 +2057,96 @@ class Schema:
                 nested_inputs.extend(input.get_all())
         input_ids = [i.id for i in nested_inputs]
         input_set = set(input_ids)
-        dynamic_input_ids = {
-            i.id for i in self.inputs if isinstance(i, (DynamicCombo.Input, DynamicSlot.Input))
-        }
-        from_input_refs = [
-            o.input_id for o in self.outputs if isinstance(o, DynamicOutputs.FromInput)
-        ]
+        combo_inputs = {i.id: i for i in self.inputs if isinstance(i, DynamicCombo.Input)}
+        slot_inputs = {i.id: i for i in self.inputs if isinstance(i, DynamicSlot.Input)}
+        # selector lookup covers both static (nested) inputs and DynamicCombo/Slot
+        # top-level inputs, since DynamicInput instances aren't included in nested_inputs.
+        all_selectable_ids = input_set | set(combo_inputs) | set(slot_inputs)
 
         # ``output_ids`` covers every id that may ever appear in a finalized
         # output list — static outputs + every option's outputs across every
-        # dynamic group + outputs from any dynamic-input referenced by a
-        # FromInput — so collisions between branches are caught up front.
+        # dynamic group — so collisions between branches are caught up front.
         output_ids: list[str] = []
         for o in self.outputs:
             if isinstance(o, Output):
                 output_ids.append(o.id)
-            elif isinstance(o, DynamicOutputs.ByKey):
+            elif isinstance(o, (DynamicOutputs.ByKey, DynamicOutputs.BySlot)):
                 for opt in o.options:
                     output_ids.extend(child.id for child in opt.outputs)
-        referenced = set(from_input_refs)
-        for inp in self.inputs:
-            if isinstance(inp, (DynamicCombo.Input, DynamicSlot.Input)) and inp.id in referenced:
-                for opt in inp.options:
-                    output_ids.extend(child.id for child in opt.outputs)
 
         output_set = set(output_ids)
         issues: list[str] = []
-        # verify ids are unique per list
         if len(input_set) != len(input_ids):
             issues.append(f"Input ids must be unique, but {[item for item, count in Counter(input_ids).items() if count > 1]} are not.")
         if len(output_set) != len(output_ids):
             issues.append(f"Output ids must be unique, but {[item for item, count in Counter(output_ids).items() if count > 1]} are not.")
-        # ByKey: unique group ids + selectors point at real (literal) inputs
+
         group_ids: list[str] = []
         for o in self.outputs:
             if isinstance(o, DynamicOutputs.ByKey):
                 group_ids.append(o.id)
-                if o.selector not in input_set:
+                if o.selector not in all_selectable_ids:
                     issues.append(
                         f"DynamicOutputs.ByKey(id={o.id!r}) selector input {o.selector!r} "
                         f"does not exist on the schema."
                     )
+                # If the selector is a DynamicCombo, every option key must match one of its keys.
+                if o.selector in combo_inputs:
+                    valid_keys = {opt.key for opt in combo_inputs[o.selector].options}
+                    stray = [opt.key for opt in o.options if opt.key not in valid_keys]
+                    if stray:
+                        issues.append(
+                            f"DynamicOutputs.ByKey(id={o.id!r}) option key(s) {stray!r} are not "
+                            f"declared on DynamicCombo input {o.selector!r} (valid: {sorted(valid_keys)!r})."
+                        )
+            elif isinstance(o, DynamicOutputs.BySlot):
+                group_ids.append(o.id)
+                if o.selector not in slot_inputs:
+                    issues.append(
+                        f"DynamicOutputs.BySlot(id={o.id!r}) selector {o.selector!r} must reference "
+                        f"a DynamicSlot input on the schema."
+                    )
+                else:
+                    slot = slot_inputs[o.selector]
+                    slot_accepted = set()
+                    slot_has_none = False
+                    for sopt in slot.options:
+                        if sopt._when_types is None:
+                            slot_has_none = True
+                        else:
+                            slot_accepted.update(sopt._when_types)
+                    for opt in o.options:
+                        if opt._when_types is None:
+                            if not slot_has_none:
+                                issues.append(
+                                    f"DynamicOutputs.BySlot(id={o.id!r}) option(when=None) requires "
+                                    f"DynamicSlot {o.selector!r} to declare a when=None option."
+                                )
+                        else:
+                            stray_types = [t for t in opt._when_types if t not in slot_accepted]
+                            if stray_types:
+                                issues.append(
+                                    f"DynamicOutputs.BySlot(id={o.id!r}) option type(s) {stray_types!r} "
+                                    f"are not accepted by DynamicSlot {o.selector!r} "
+                                    f"(accepted: {sorted(slot_accepted)!r})."
+                                )
         if len(set(group_ids)) != len(group_ids):
             issues.append(
                 f"DynamicOutputs group ids must be unique, but "
                 f"{[i for i, c in Counter(group_ids).items() if c > 1]} are not."
             )
-        # FromInput: each ref points at a DynamicCombo / DynamicSlot input and is unique
-        for ref in from_input_refs:
-            if ref not in dynamic_input_ids:
-                issues.append(
-                    f"DynamicOutputs.FromInput(input_id={ref!r}) must reference a "
-                    f"DynamicCombo or DynamicSlot input on the schema."
-                )
-        if len(set(from_input_refs)) != len(from_input_refs):
-            issues.append(
-                f"DynamicOutputs.FromInput: each input may be referenced at most once, but "
-                f"{[r for r, c in Counter(from_input_refs).items() if c > 1]} are referenced more than once."
-            )
         if len(issues) > 0:
             raise ValueError("\n".join(issues))
-        # validate inputs and outputs
+        # per-element validation
         for input in self.inputs:
             input.validate()
         for output in self.outputs:
             if isinstance(output, Output):
                 output.validate()
-            elif isinstance(output, DynamicOutputs.ByKey):
+            elif isinstance(output, (DynamicOutputs.ByKey, DynamicOutputs.BySlot)):
                 for opt in output.options:
                     for child in opt.outputs:
                         child.validate()
-        # Validate option-outputs declared on dynamic inputs (whether referenced or not).
-        for inp in self.inputs:
-            if isinstance(inp, (DynamicCombo.Input, DynamicSlot.Input)):
-                for opt in inp.options:
-                    for child in opt.outputs:
-                        child.validate()
         if self.price_badge is not None:
             self.price_badge.validate()
 
@@ -2205,19 +2193,11 @@ class Schema:
         output_matchtypes = []
         any_matchtypes = False
         dynamic_outputs: list[dict[str, Any]] = []
-        dynamic_inputs_by_id = {
-            i.id: i for i in self.inputs if isinstance(i, (DynamicCombo.Input, DynamicSlot.Input))
-        }
         if self.outputs:
             for o in self.outputs:
-                if isinstance(o, DynamicOutputs.ByKey):
+                if isinstance(o, (DynamicOutputs.ByKey, DynamicOutputs.BySlot)):
                     dynamic_outputs.append(o.as_dict())
                     continue
-                if isinstance(o, DynamicOutputs.FromInput):
-                    source = dynamic_inputs_by_id.get(o.input_id)
-                    if source is not None:
-                        dynamic_outputs.append(_from_input_as_dict(o, source))
-                    continue
                 output.append(o.io_type)
                 output_is_list.append(o.is_output_list)
                 output_name.append(o.display_name if o.display_name else o.io_type)

comfy_execution/type_resolver.py

@@ -235,9 +235,8 @@ class TypeResolver:
     def _get_finalized_outputs(self, node_id: str, node: dict | None, class_def) -> io.FinalizedOutputs | None:
         """Return ``FinalizedOutputs`` for V3 nodes with DynamicOutputs groups, else ``None``.
 
-        ``FromInput`` placeholders for ``DynamicSlot`` inputs also need
-        ``live_input_types`` (computed lazily from the resolver itself) so
-        the active option can be picked by resolved upstream type.
+        ``BySlot`` groups need ``live_input_types`` (computed lazily from the
+        resolver itself) so the active option can be picked by resolved type.
         """
         if not (isinstance(class_def, type) and issubclass(class_def, _ComfyNodeInternal)):
             return None
@@ -246,25 +245,18 @@ class TypeResolver:
         except Exception:
             return None
         has_dynamic = any(
-            isinstance(o, (io.DynamicOutputs.ByKey, io.DynamicOutputs.FromInput))
+            isinstance(o, (io.DynamicOutputs.ByKey, io.DynamicOutputs.BySlot))
             for o in schema.outputs
         )
         if not has_dynamic:
             return None
         prompt_inputs = (node or {}).get("inputs", {}) or {}
-        # live_input_types is only needed for FromInput → DynamicSlot; skip the
-        # resolver pass otherwise to keep the hot path cheap.
-        needs_live_types = any(
-            isinstance(o, io.DynamicOutputs.FromInput)
-            and any(isinstance(i, io.DynamicSlot.Input) and i.id == o.input_id for i in schema.inputs)
-            for o in schema.outputs
-        )
+        # live_input_types is only needed for BySlot — skip the resolver pass
+        # otherwise to keep the hot path cheap.
+        needs_live_types = any(isinstance(o, io.DynamicOutputs.BySlot) for o in schema.outputs)
         live_input_types = self.compute_live_input_types(node_id) if needs_live_types else None
         return io.get_finalized_class_outputs(
-            schema.outputs,
-            prompt_inputs,
-            schema_inputs=schema.inputs,
-            live_input_types=live_input_types,
+            schema.outputs, prompt_inputs, live_input_types=live_input_types,
         )
 
     def finalized_output_count(self, node_id: str) -> int:

execution.py

@@ -504,23 +504,17 @@ async def execute(server, dynprompt, caches, current_item, extra_data, executed,
     if issubclass(class_def, _ComfyNodeInternal):
         schema = class_def.GET_SCHEMA()
         has_dynamic = any(
-            isinstance(o, (_io.DynamicOutputs.ByKey, _io.DynamicOutputs.FromInput))
+            isinstance(o, (_io.DynamicOutputs.ByKey, _io.DynamicOutputs.BySlot))
             for o in schema.outputs
         )
         if has_dynamic:
-            # live_input_types is only needed for FromInput → DynamicSlot finalization
-            needs_live_types = any(
-                isinstance(o, _io.DynamicOutputs.FromInput)
-                and any(isinstance(i, _io.DynamicSlot.Input) and i.id == o.input_id for i in schema.inputs)
-                for o in schema.outputs
-            )
+            # live_input_types is only needed for BySlot finalization.
+            needs_live_types = any(isinstance(o, _io.DynamicOutputs.BySlot) for o in schema.outputs)
             live_input_types = None
             if needs_live_types and hasattr(dynprompt, "get_type_resolver"):
                 live_input_types = dynprompt.get_type_resolver().compute_live_input_types(unique_id)
             finalized_outputs = _io.get_finalized_class_outputs(
-                schema.outputs, inputs,
-                schema_inputs=schema.inputs,
-                live_input_types=live_input_types,
+                schema.outputs, inputs, live_input_types=live_input_types,
             )
 
     input_data_all = None

tests-unit/comfy_api_test/test_dynamic_outputs.py

@@ -235,198 +235,197 @@ def test_schema_rejects_duplicate_dynamic_group_ids():
 
 
 # ---------------------------------------------------------------------------
-# DynamicOutputs.FromInput — DynamicCombo / DynamicSlot integration
+# DynamicOutputs.ByKey with a DynamicCombo selector
 # ---------------------------------------------------------------------------
 
-def _combo_options_with_outputs():
-    return [
-        io.DynamicCombo.Option(
-            key="image",
-            inputs=[io.Image.Input("img")],
-            outputs=[io.Image.Output("processed"), io.Mask.Output("alpha")],
-        ),
-        io.DynamicCombo.Option(
-            key="latent",
-            inputs=[io.Latent.Input("lat")],
-            outputs=[io.Latent.Output("denoised")],
-        ),
-    ]
+def _combo_input():
+    return io.DynamicCombo.Input("mode", options=[
+        io.DynamicCombo.Option(key="image", inputs=[io.Image.Input("img")]),
+        io.DynamicCombo.Option(key="latent", inputs=[io.Latent.Input("lat")]),
+    ])
 
 
-def _slot_options_with_outputs():
-    return [
-        io.DynamicSlot.Option(
-            when=io.Image,
-            outputs=[io.Image.Output("processed"), io.Mask.Output("alpha")],
-        ),
-        io.DynamicSlot.Option(
-            when=io.Latent,
-            outputs=[io.Latent.Output("denoised")],
-        ),
-        io.DynamicSlot.Option(
-            when=None,
-            inputs=[io.Int.Input("seed")],
-            outputs=[],
-        ),
-    ]
+def _bykey_outputs():
+    return io.DynamicOutputs.ByKey(id="result", selector="mode", options=[
+        io.DynamicOutputs.Option(key="image", outputs=[io.Image.Output("processed"), io.Mask.Output("alpha")]),
+        io.DynamicOutputs.Option(key="latent", outputs=[io.Latent.Output("denoised")]),
+    ])
 
 
-def test_fromInput_finalizes_combo_branch():
-    schema_inputs = [io.DynamicCombo.Input("mode", options=_combo_options_with_outputs())]
-    schema_outputs = [io.String.Output("status"), io.DynamicOutputs.FromInput("mode")]
+def test_bykey_with_dynamic_combo_finalizes_branch():
     finalized = io.get_finalized_class_outputs(
-        schema_outputs, {"mode": "image"}, schema_inputs=schema_inputs,
+        [io.String.Output("status"), _bykey_outputs()],
+        {"mode": {"mode": "image", "img": None}},  # DynamicCombo dispatch shape
     )
     assert finalized.output_ids == ["status", "processed", "alpha"]
     assert finalized.return_types == ["STRING", "IMAGE", "MASK"]
 
 
-def test_fromInput_unknown_combo_key_yields_only_static():
-    schema_inputs = [io.DynamicCombo.Input("mode", options=_combo_options_with_outputs())]
-    schema_outputs = [io.String.Output("status"), io.DynamicOutputs.FromInput("mode")]
+def test_bykey_with_dynamic_combo_other_branch():
     finalized = io.get_finalized_class_outputs(
-        schema_outputs, {"mode": "missing"}, schema_inputs=schema_inputs,
+        [_bykey_outputs()],
+        {"mode": {"mode": "latent", "lat": None}},
     )
-    assert finalized.output_ids == ["status"]
+    assert finalized.output_ids == ["denoised"]
 
 
-def test_fromInput_finalizes_slot_by_resolved_type():
-    schema_inputs = [io.DynamicSlot.Input("slot", options=_slot_options_with_outputs())]
-    schema_outputs = [io.DynamicOutputs.FromInput("slot")]
-    # Connected with resolved type IMAGE → first option matches
+def test_schema_rejects_bykey_key_not_on_dynamic_combo():
+    class StrayKey(io.ComfyNode):
+        @classmethod
+        def define_schema(cls):
+            return io.Schema(
+                node_id="StrayKey",
+                inputs=[_combo_input()],
+                outputs=[io.DynamicOutputs.ByKey(id="r", selector="mode", options=[
+                    io.DynamicOutputs.Option(key="image", outputs=[io.Image.Output("a")]),
+                    io.DynamicOutputs.Option(key="audio", outputs=[io.String.Output("b")]),
+                ])],
+            )
+
+        @classmethod
+        def execute(cls, **kwargs):
+            return io.NodeOutput.from_named({})
+
+    with pytest.raises(ValueError, match=r"option key\(s\) \['audio'\] are not declared"):
+        StrayKey.GET_SCHEMA()
+
+
+# ---------------------------------------------------------------------------
+# DynamicOutputs.BySlot
+# ---------------------------------------------------------------------------
+
+def _slot_input():
+    return io.DynamicSlot.Input("slot", options=[
+        io.DynamicSlot.Option(when=io.Image),
+        io.DynamicSlot.Option(when=io.Latent),
+        io.DynamicSlot.Option(when=None, inputs=[io.Int.Input("seed")]),
+    ])
+
+
+def _byslot_outputs():
+    return io.DynamicOutputs.BySlot(id="slot_out", selector="slot", options=[
+        io.DynamicOutputs.SlotOption(when=io.Image, outputs=[io.Image.Output("processed"), io.Mask.Output("alpha")]),
+        io.DynamicOutputs.SlotOption(when=io.Latent, outputs=[io.Latent.Output("denoised")]),
+        io.DynamicOutputs.SlotOption(when=None, outputs=[]),
+    ])
+
+
+def test_byslot_finalizes_by_resolved_type():
     finalized = io.get_finalized_class_outputs(
-        schema_outputs,
+        [_byslot_outputs()],
         {"slot": ["upstream", 0]},
-        schema_inputs=schema_inputs,
         live_input_types={"slot": "IMAGE"},
     )
     assert finalized.output_ids == ["processed", "alpha"]
-    # Connected, LATENT branch
     finalized = io.get_finalized_class_outputs(
-        schema_outputs,
+        [_byslot_outputs()],
         {"slot": ["upstream", 0]},
-        schema_inputs=schema_inputs,
         live_input_types={"slot": "LATENT"},
     )
     assert finalized.output_ids == ["denoised"]
 
 
-def test_fromInput_slot_unconnected_uses_when_none_option():
-    schema_inputs = [io.DynamicSlot.Input("slot", options=_slot_options_with_outputs())]
-    schema_outputs = [io.DynamicOutputs.FromInput("slot")]
-    finalized = io.get_finalized_class_outputs(
-        schema_outputs, {}, schema_inputs=schema_inputs,
-    )
+def test_byslot_unconnected_uses_when_none():
+    finalized = io.get_finalized_class_outputs([_byslot_outputs()], {})
     # when=None option declares outputs=[] → no active outputs
     assert finalized.output_ids == []
 
 
-def test_fromInput_slot_unmatched_type_yields_empty():
-    """Resolved upstream type with no matching option contributes no slots."""
-    schema_inputs = [io.DynamicSlot.Input("slot", options=_slot_options_with_outputs())]
-    schema_outputs = [io.DynamicOutputs.FromInput("slot")]
+def test_byslot_unmatched_type_yields_empty():
     finalized = io.get_finalized_class_outputs(
-        schema_outputs,
+        [_byslot_outputs()],
         {"slot": ["upstream", 0]},
-        schema_inputs=schema_inputs,
         live_input_types={"slot": "AUDIO"},
     )
     assert finalized.output_ids == []
 
 
-def test_schema_rejects_fromInput_pointing_at_missing_input():
-    class BadRef(io.ComfyNode):
+def test_byslot_rejects_duplicate_when_types():
+    with pytest.raises(ValueError, match="appears in more than one option"):
+        io.DynamicOutputs.BySlot(id="r", selector="slot", options=[
+            io.DynamicOutputs.SlotOption(when=io.Image, outputs=[io.Image.Output("a")]),
+            io.DynamicOutputs.SlotOption(when=io.Image, outputs=[io.Mask.Output("b")]),
+        ])
+
+
+def test_byslot_rejects_duplicate_when_none():
+    with pytest.raises(ValueError, match="only one option may declare when=None"):
+        io.DynamicOutputs.BySlot(id="r", selector="slot", options=[
+            io.DynamicOutputs.SlotOption(when=None, outputs=[]),
+            io.DynamicOutputs.SlotOption(when=None, outputs=[io.Image.Output("x")]),
+        ])
+
+
+def test_schema_rejects_byslot_selector_not_a_dynamic_slot():
+    class WrongSel(io.ComfyNode):
         @classmethod
         def define_schema(cls):
             return io.Schema(
-                node_id="BadRef",
-                inputs=[io.Combo.Input("mode", options=["a"])],
-                outputs=[io.DynamicOutputs.FromInput("does_not_exist")],
+                node_id="WrongSel",
+                inputs=[io.Combo.Input("not_a_slot", options=["a"])],
+                outputs=[io.DynamicOutputs.BySlot(id="r", selector="not_a_slot", options=[
+                    io.DynamicOutputs.SlotOption(when=io.Image, outputs=[io.Image.Output("x")]),
+                ])],
             )
 
         @classmethod
         def execute(cls, **kwargs):
             return io.NodeOutput.from_named({})
 
-    with pytest.raises(ValueError, match="must reference a DynamicCombo or DynamicSlot"):
-        BadRef.GET_SCHEMA()
+    with pytest.raises(ValueError, match="must reference a DynamicSlot input"):
+        WrongSel.GET_SCHEMA()
 
 
-def test_schema_rejects_fromInput_referenced_more_than_once():
-    class DupRef(io.ComfyNode):
+def test_schema_rejects_byslot_when_type_not_on_slot():
+    class StrayWhen(io.ComfyNode):
         @classmethod
         def define_schema(cls):
             return io.Schema(
-                node_id="DupRef",
-                inputs=[io.DynamicCombo.Input("mode", options=_combo_options_with_outputs())],
-                outputs=[io.DynamicOutputs.FromInput("mode"), io.DynamicOutputs.FromInput("mode")],
+                node_id="StrayWhen",
+                inputs=[_slot_input()],
+                outputs=[io.DynamicOutputs.BySlot(id="r", selector="slot", options=[
+                    io.DynamicOutputs.SlotOption(when=io.Audio, outputs=[io.Audio.Output("x")]),
+                ])],
             )
 
         @classmethod
         def execute(cls, **kwargs):
             return io.NodeOutput.from_named({})
 
-    with pytest.raises(ValueError, match="referenced more than once"):
-        DupRef.GET_SCHEMA()
+    with pytest.raises(ValueError, match=r"type\(s\) \['AUDIO'\] are not accepted"):
+        StrayWhen.GET_SCHEMA()
 
 
-def test_schema_rejects_fromInput_output_collision_with_static():
-    class Collision(io.ComfyNode):
+def test_schema_rejects_byslot_when_none_without_slot_when_none():
+    class NoNone(io.ComfyNode):
         @classmethod
         def define_schema(cls):
             return io.Schema(
-                node_id="Collision",
-                inputs=[
-                    io.DynamicCombo.Input("mode", options=[
-                        io.DynamicCombo.Option(
-                            key="image", inputs=[io.Image.Input("img")],
-                            outputs=[io.Image.Output("processed")],
-                        ),
-                    ]),
-                ],
-                outputs=[io.Image.Output("processed"), io.DynamicOutputs.FromInput("mode")],
+                node_id="NoNone",
+                inputs=[io.DynamicSlot.Input("slot", optional=False, options=[
+                    io.DynamicSlot.Option(when=io.Image),
+                ])],
+                outputs=[io.DynamicOutputs.BySlot(id="r", selector="slot", options=[
+                    io.DynamicOutputs.SlotOption(when=None, outputs=[]),
+                ])],
             )
 
         @classmethod
         def execute(cls, **kwargs):
-            return io.NodeOutput.from_named({"processed": None})
+            return io.NodeOutput.from_named({})
 
-    with pytest.raises(ValueError, match="Output ids must be unique"):
-        Collision.GET_SCHEMA()
+    with pytest.raises(ValueError, match="requires DynamicSlot 'slot' to declare a when=None"):
+        NoNone.GET_SCHEMA()
 
 
-def test_v1_info_emits_by_key_for_combo_fromInput():
+def test_v1_info_emits_byslot_entry():
     class N(io.ComfyNode):
         @classmethod
         def define_schema(cls):
             return io.Schema(
-                node_id="ComboFI",
-                inputs=[io.DynamicCombo.Input("mode", options=_combo_options_with_outputs())],
-                outputs=[io.DynamicOutputs.FromInput("mode")],
-            )
-
-        @classmethod
-        def execute(cls, **kwargs):
-            return io.NodeOutput.from_named({})
-
-    N.GET_SCHEMA()
-    info = N.SCHEMA.get_v1_info(N)
-    assert info.dynamic_outputs is not None and len(info.dynamic_outputs) == 1
-    entry = info.dynamic_outputs[0]
-    assert entry["kind"] == "by_key"
-    assert entry["selector"] == "mode"
-    keys = {opt["key"] for opt in entry["options"]}
-    assert keys == {"image", "latent"}
-
-
-def test_v1_info_emits_by_slot_for_slot_fromInput():
-    class N(io.ComfyNode):
-        @classmethod
-        def define_schema(cls):
-            return io.Schema(
-                node_id="SlotFI",
-                inputs=[io.DynamicSlot.Input("slot", options=_slot_options_with_outputs())],
-                outputs=[io.DynamicOutputs.FromInput("slot")],
+                node_id="SlotV1",
+                inputs=[_slot_input()],
+                outputs=[_byslot_outputs()],
             )
 
         @classmethod

tests-unit/execution_test/test_dynamic_outputs_resolver.py

@@ -256,79 +256,78 @@ def test_blocker_sized_to_finalized_outputs_for_node_output():
 
 
 # ---------------------------------------------------------------------------
-# FromInput via DynamicCombo / DynamicSlot through the TypeResolver
+# DynamicOutputs.ByKey driven by a DynamicCombo selector (end-to-end resolver)
 # ---------------------------------------------------------------------------
 
-def _make_combo_fi_node():
-    """V3 node: DynamicCombo input drives output set via FromInput placeholder."""
+def _make_combo_bykey_node():
     from comfy_api.latest import _io as io
 
-    class ComboFI(io.ComfyNode):
+    class ComboBK(io.ComfyNode):
         @classmethod
         def define_schema(cls):
             return io.Schema(
-                node_id="ComboFI",
+                node_id="ComboBK",
                 inputs=[
                     io.DynamicCombo.Input("mode", options=[
-                        io.DynamicCombo.Option(
-                            key="image",
-                            inputs=[io.Image.Input("img")],
-                            outputs=[io.Image.Output("processed"), io.Mask.Output("alpha")],
-                        ),
-                        io.DynamicCombo.Option(
-                            key="latent",
-                            inputs=[io.Latent.Input("lat")],
-                            outputs=[io.Latent.Output("denoised")],
-                        ),
+                        io.DynamicCombo.Option(key="image", inputs=[io.Image.Input("img")]),
+                        io.DynamicCombo.Option(key="latent", inputs=[io.Latent.Input("lat")]),
                     ]),
                 ],
-                outputs=[io.DynamicOutputs.FromInput("mode")],
+                outputs=[io.DynamicOutputs.ByKey(id="result", selector="mode", options=[
+                    io.DynamicOutputs.Option(key="image",
+                        outputs=[io.Image.Output("processed"), io.Mask.Output("alpha")]),
+                    io.DynamicOutputs.Option(key="latent",
+                        outputs=[io.Latent.Output("denoised")]),
+                ])],
             )
 
         @classmethod
         def execute(cls, mode, **kwargs):
-            if mode == "latent":
+            if mode["mode"] == "latent":
                 return io.NodeOutput.from_named({"denoised": None})
             return io.NodeOutput.from_named({"processed": None, "alpha": None})
 
-    ComboFI.GET_SCHEMA()
-    return ComboFI
+    ComboBK.GET_SCHEMA()
+    return ComboBK
 
 
-def _make_slot_fi_node():
-    """V3 node: DynamicSlot input drives output set via FromInput placeholder."""
+def _make_slot_byslot_node():
     from comfy_api.latest import _io as io
 
-    class SlotFI(io.ComfyNode):
+    class SlotBS(io.ComfyNode):
         @classmethod
         def define_schema(cls):
             return io.Schema(
-                node_id="SlotFI",
+                node_id="SlotBS",
                 inputs=[
                     io.DynamicSlot.Input("slot", options=[
-                        io.DynamicSlot.Option(when=io.Image,
-                            outputs=[io.Image.Output("processed"), io.Mask.Output("alpha")]),
-                        io.DynamicSlot.Option(when=io.Latent,
-                            outputs=[io.Latent.Output("denoised")]),
-                        io.DynamicSlot.Option(when=None, outputs=[]),
+                        io.DynamicSlot.Option(when=io.Image),
+                        io.DynamicSlot.Option(when=io.Latent),
+                        io.DynamicSlot.Option(when=None),
                     ]),
                 ],
-                outputs=[io.DynamicOutputs.FromInput("slot")],
+                outputs=[io.DynamicOutputs.BySlot(id="slot_out", selector="slot", options=[
+                    io.DynamicOutputs.SlotOption(when=io.Image,
+                        outputs=[io.Image.Output("processed"), io.Mask.Output("alpha")]),
+                    io.DynamicOutputs.SlotOption(when=io.Latent,
+                        outputs=[io.Latent.Output("denoised")]),
+                    io.DynamicOutputs.SlotOption(when=None, outputs=[]),
+                ])],
             )
 
         @classmethod
         def execute(cls, **kwargs):
             return io.NodeOutput.from_named({})
 
-    SlotFI.GET_SCHEMA()
-    return SlotFI
+    SlotBS.GET_SCHEMA()
+    return SlotBS
 
 
-def test_combo_fromInput_resolver_picks_branch(fake_nodes_module, TypeResolver):
-    fake_nodes_module["ComboFI"] = _make_combo_fi_node()
+def test_combo_bykey_resolver_picks_branch(fake_nodes_module, TypeResolver):
+    fake_nodes_module["ComboBK"] = _make_combo_bykey_node()
     prompt = {
-        "img": {"class_type": "ComboFI", "inputs": {"mode": "image"}},
-        "lat": {"class_type": "ComboFI", "inputs": {"mode": "latent"}},
+        "img": {"class_type": "ComboBK", "inputs": {"mode": {"mode": "image", "img": None}}},
+        "lat": {"class_type": "ComboBK", "inputs": {"mode": {"mode": "latent", "lat": None}}},
     }
     r = TypeResolver(prompt)
     assert r.resolve_output_type("img", 0) == "IMAGE"
@@ -338,22 +337,22 @@ def test_combo_fromInput_resolver_picks_branch(fake_nodes_module, TypeResolver):
     assert r.finalized_output_count("lat") == 1
 
 
-def test_slot_fromInput_resolver_picks_by_resolved_type(fake_nodes_module, TypeResolver):
-    fake_nodes_module["SlotFI"] = _make_slot_fi_node()
+def test_slot_byslot_resolver_picks_by_resolved_type(fake_nodes_module, TypeResolver):
+    fake_nodes_module["SlotBS"] = _make_slot_byslot_node()
     fake_nodes_module["ImageSrc"] = _v1_node(("IMAGE",))
     fake_nodes_module["LatentSrc"] = _v1_node(("LATENT",))
     prompt = {
         "img_src": {"class_type": "ImageSrc", "inputs": {}},
         "lat_src": {"class_type": "LatentSrc", "inputs": {}},
-        "image_consumer": {"class_type": "SlotFI", "inputs": {"slot": ["img_src", 0]}},
-        "latent_consumer": {"class_type": "SlotFI", "inputs": {"slot": ["lat_src", 0]}},
-        "unconnected": {"class_type": "SlotFI", "inputs": {}},
+        "image_consumer": {"class_type": "SlotBS", "inputs": {"slot": ["img_src", 0]}},
+        "latent_consumer": {"class_type": "SlotBS", "inputs": {"slot": ["lat_src", 0]}},
+        "unconnected": {"class_type": "SlotBS", "inputs": {}},
     }
     r = TypeResolver(prompt)
     assert r.resolve_output_type("image_consumer", 0) == "IMAGE"
     assert r.resolve_output_type("image_consumer", 1) == "MASK"
     assert r.resolve_output_type("latent_consumer", 0) == "LATENT"
-    # Unconnected: when=None option declares outputs=[] → finalized count is 0.
+    # Unconnected → when=None branch declares outputs=[]
     assert r.finalized_output_count("unconnected") == 0