Merge branch 'master' into feat/string-min-max-length

When training_dtype is set to "none" and the model's native dtype is
float16, GradScaler was unconditionally enabled. However, GradScaler
does not support bfloat16 gradients (only float16/float32), causing a
NotImplementedError when lora_dtype is "bf16" (the default).

Fix by only enabling GradScaler when LoRA parameters are not in
bfloat16, since bfloat16 has the same exponent range as float32 and
does not need gradient scaling to avoid underflow.

Fixes #13124

comfy_api/latest/_io.py

@@ -326,11 +326,14 @@ class String(ComfyTypeIO):
         '''String input.'''
         def __init__(self, id: str, display_name: str=None, optional=False, tooltip: str=None, lazy: bool=None,
                     multiline=False, placeholder: str=None, default: str=None, dynamic_prompts: bool=None,
-                    socketless: bool=None, force_input: bool=None, extra_dict=None, raw_link: bool=None, advanced: bool=None):
+                    socketless: bool=None, force_input: bool=None, extra_dict=None, raw_link: bool=None, advanced: bool=None,
+                    min_length: int=None, max_length: int=None):
             super().__init__(id, display_name, optional, tooltip, lazy, default, socketless, None, force_input, extra_dict, raw_link, advanced)
             self.multiline = multiline
             self.placeholder = placeholder
             self.dynamic_prompts = dynamic_prompts
+            self.min_length = min_length
+            self.max_length = max_length
             self.default: str
 
         def as_dict(self):
@@ -338,6 +341,8 @@ class String(ComfyTypeIO):
                 "multiline": self.multiline,
                 "placeholder": self.placeholder,
                 "dynamicPrompts": self.dynamic_prompts,
+                "minLength": self.min_length,
+                "maxLength": self.max_length,
             })
 
 @comfytype(io_type="COMBO")

comfy_extras/nodes_train.py

@@ -1146,6 +1146,7 @@ class TrainLoraNode(io.ComfyNode):
         # Setup model and dtype
         mp = model.clone()
         use_grad_scaler = False
+        lora_dtype = node_helpers.string_to_torch_dtype(lora_dtype)
         if training_dtype != "none":
             dtype = node_helpers.string_to_torch_dtype(training_dtype)
             mp.set_model_compute_dtype(dtype)
@@ -1154,7 +1155,10 @@ class TrainLoraNode(io.ComfyNode):
             model_dtype = mp.model.get_dtype()
             if model_dtype == torch.float16:
                 dtype = torch.float16
-                use_grad_scaler = True
+                # GradScaler only supports float16 gradients, not bfloat16.
+                # Only enable it when lora params will also be in float16.
+                if lora_dtype != torch.bfloat16:
+                    use_grad_scaler = True
                 # Warn about fp16 accumulation instability during training
                 if PerformanceFeature.Fp16Accumulation in args.fast:
                     logging.warning(
@@ -1165,7 +1169,6 @@ class TrainLoraNode(io.ComfyNode):
             else:
                 # For fp8, bf16, or other dtypes, use bf16 autocast
                 dtype = torch.bfloat16
-        lora_dtype = node_helpers.string_to_torch_dtype(lora_dtype)
 
         # Prepare latents and compute counts
         latents_dtype = dtype if dtype not in (None,) else torch.bfloat16

execution.py

@@ -82,7 +82,7 @@ class IsChangedCache:
             return self.is_changed[node_id]
 
         # Intentionally do not use cached outputs here. We only want constants in IS_CHANGED
-        input_data_all, _, v3_data = get_input_data(node["inputs"], class_def, node_id, None)
+        input_data_all, _, v3_data, _ = get_input_data(node["inputs"], class_def, node_id, None)
         try:
             is_changed = await _async_map_node_over_list(self.prompt_id, node_id, class_def, input_data_all, is_changed_name, v3_data=v3_data)
             is_changed = await resolve_map_node_over_list_results(is_changed)
@@ -214,7 +214,35 @@ def get_input_data(inputs, class_def, unique_id, execution_list=None, dynprompt=
                 if h[x] == "API_KEY_COMFY_ORG":
                     input_data_all[x] = [extra_data.get("api_key_comfy_org", None)]
     v3_data["hidden_inputs"] = hidden_inputs_v3
-    return input_data_all, missing_keys, v3_data
+    return input_data_all, missing_keys, v3_data, valid_inputs
+
+def validate_resolved_inputs(input_data_all, class_def, valid_inputs):
+    """Validate resolved input values against schema constraints.
+
+    This is needed because validate_inputs() only sees direct widget values.
+    Linked inputs aren't resolved during validate_inputs(), so this runs after resolution to catch any violations.
+    """
+    for x, values in input_data_all.items():
+        input_type, input_category, extra_info = get_input_info(class_def, x, valid_inputs)
+        if input_type != "STRING":
+            continue
+        min_length = extra_info.get("minLength")
+        max_length = extra_info.get("maxLength")
+        if min_length is None and max_length is None:
+            continue
+        for val in values:
+            if val is None or not isinstance(val, str):
+                continue
+            if min_length is not None and len(val) < min_length:
+                raise ValueError(
+                    f"Input '{x}': value length {len(val)} is shorter than "
+                    f"minimum length of {min_length}"
+                )
+            if max_length is not None and len(val) > max_length:
+                raise ValueError(
+                    f"Input '{x}': value length {len(val)} is longer than "
+                    f"maximum length of {max_length}"
+                )
 
 map_node_over_list = None #Don't hook this please
 
@@ -470,7 +498,7 @@ async def execute(server, dynprompt, caches, current_item, extra_data, executed,
             has_subgraph = False
         else:
             get_progress_state().start_progress(unique_id)
-            input_data_all, missing_keys, v3_data = get_input_data(inputs, class_def, unique_id, execution_list, dynprompt, extra_data)
+            input_data_all, missing_keys, v3_data, valid_inputs = get_input_data(inputs, class_def, unique_id, execution_list, dynprompt, extra_data)
             if server.client_id is not None:
                 server.last_node_id = display_node_id
                 server.send_sync("executing", { "node": unique_id, "display_node": display_node_id, "prompt_id": prompt_id }, server.client_id)
@@ -499,6 +527,8 @@ async def execute(server, dynprompt, caches, current_item, extra_data, executed,
                         execution_list.make_input_strong_link(unique_id, i)
                     return (ExecutionResult.PENDING, None, None)
 
+            validate_resolved_inputs(input_data_all, class_def, valid_inputs)
+
             def execution_block_cb(block):
                 if block.message is not None:
                     mes = {
@@ -963,6 +993,34 @@ async def validate_inputs(prompt_id, prompt, item, validated):
                     errors.append(error)
                     continue
 
+                if input_type == "STRING":
+                    if "minLength" in extra_info and len(val) < extra_info["minLength"]:
+                        error = {
+                            "type": "value_shorter_than_min_length",
+                            "message": "Value length {} shorter than min length of {}".format(len(val), extra_info["minLength"]),
+                            "details": f"{x}",
+                            "extra_info": {
+                                "input_name": x,
+                                "input_config": info,
+                                "received_value": val,
+                            }
+                        }
+                        errors.append(error)
+                        continue
+                    if "maxLength" in extra_info and len(val) > extra_info["maxLength"]:
+                        error = {
+                            "type": "value_longer_than_max_length",
+                            "message": "Value length {} longer than max length of {}".format(len(val), extra_info["maxLength"]),
+                            "details": f"{x}",
+                            "extra_info": {
+                                "input_name": x,
+                                "input_config": info,
+                                "received_value": val,
+                            }
+                        }
+                        errors.append(error)
+                        continue
+
                 if isinstance(input_type, list) or input_type == io.Combo.io_type:
                     if input_type == io.Combo.io_type:
                         combo_options = extra_info.get("options", [])
@@ -994,7 +1052,7 @@ async def validate_inputs(prompt_id, prompt, item, validated):
                         continue
 
     if len(validate_function_inputs) > 0 or validate_has_kwargs:
-        input_data_all, _, v3_data = get_input_data(inputs, obj_class, unique_id)
+        input_data_all, _, v3_data, _ = get_input_data(inputs, obj_class, unique_id)
         input_filtered = {}
         for x in input_data_all:
             if x in validate_function_inputs or validate_has_kwargs:

tests/execution/test_execution.py

@@ -1011,3 +1011,49 @@ class TestExecution:
         """Test getting a non-existent job returns 404"""
         job = client.get_job("nonexistent-job-id")
         assert job is None, "Non-existent job should return None"
+
+
+    @pytest.mark.parametrize("text, expect_error", [
+        ("hello", False),       # 5 chars, within [3, 10]
+        ("abc", False),         # 3 chars, exact min boundary
+        ("abcdefghij", False),  # 10 chars, exact max boundary
+        ("ab", True),           # 2 chars, below min
+        ("abcdefghijk", True),  # 11 chars, above max
+        ("", True),             # 0 chars, below min
+    ])
+    def test_string_length_widget_validation(self, text, expect_error, client: ComfyClient, builder: GraphBuilder):
+        """Test minLength/maxLength validation for direct widget values (validate_inputs path)."""
+        g = builder
+        node = g.node("StubStringWithLength", text=text)
+        g.node("SaveImage", images=node.out(0))
+        if expect_error:
+            with pytest.raises(urllib.error.HTTPError) as exc_info:
+                client.run(g)
+            assert exc_info.value.code == 400
+        else:
+            client.run(g)
+
+
+    @pytest.mark.parametrize("text, expect_error", [
+        ("hello", False),       # 5 chars, within [3, 10]
+        ("abc", False),         # 3 chars, exact min boundary
+        ("abcdefghij", False),  # 10 chars, exact max boundary
+        ("ab", True),           # 2 chars, below min
+        ("abcdefghijk", True),  # 11 chars, above max
+        ("", True),             # 0 chars, below min
+    ])
+    def test_string_length_linked_validation(self, text, expect_error, client: ComfyClient, builder: GraphBuilder):
+        """Test minLength/maxLength validation for linked inputs (validate_resolved_inputs path)."""
+        g = builder
+        str_node = g.node("StubStringOutput", value=text)
+        node = g.node("StubStringWithLength", text=str_node.out(0))
+        g.node("SaveImage", images=node.out(0))
+
+        if expect_error:
+            try:
+                client.run(g)
+                assert False, "Should have raised an error"
+            except Exception as e:
+                assert 'prompt_id' in e.args[0], f"Did not get proper error message: {e}"
+        else:
+            client.run(g)

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

@@ -113,12 +113,48 @@ class StubFloat:
     def stub_float(self, value):
         return (value,)
 
+class StubStringOutput:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "value": ("STRING", {"default": ""}),
+            },
+        }
+
+    RETURN_TYPES = ("STRING",)
+    FUNCTION = "stub_string"
+
+    CATEGORY = "Testing/Stub Nodes"
+
+    def stub_string(self, value):
+        return (value,)
+
+class StubStringWithLength:
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "text": ("STRING", {"default": "hello", "minLength": 3, "maxLength": 10}),
+            },
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "stub_string_with_length"
+
+    CATEGORY = "Testing/Stub Nodes"
+
+    def stub_string_with_length(self, text):
+        return (torch.zeros(1, 64, 64, 3),)
+
 TEST_STUB_NODE_CLASS_MAPPINGS = {
     "StubImage": StubImage,
     "StubConstantImage": StubConstantImage,
     "StubMask": StubMask,
     "StubInt": StubInt,
     "StubFloat": StubFloat,
+    "StubStringOutput": StubStringOutput,
+    "StubStringWithLength": StubStringWithLength,
 }
 TEST_STUB_NODE_DISPLAY_NAME_MAPPINGS = {
     "StubImage": "Stub Image",
@@ -126,4 +162,6 @@ TEST_STUB_NODE_DISPLAY_NAME_MAPPINGS = {
     "StubMask": "Stub Mask",
     "StubInt": "Stub Int",
     "StubFloat": "Stub Float",
+    "StubStringOutput": "Stub String Output",
+    "StubStringWithLength": "Stub String With Length",
 }