Fix code formatting and add MissingDefault class

src/backend/langflow/interface/custom/code_parser/code_parser.py

@@ -9,7 +9,11 @@ from fastapi import HTTPException
 from loguru import logger
 
 from langflow.interface.custom.eval import eval_custom_component_code
-from langflow.interface.custom.schema import CallableCodeDetails, ClassCodeDetails
+from langflow.interface.custom.schema import (
+    CallableCodeDetails,
+    ClassCodeDetails,
+    MissingDefault,
+)
 
 
 class CodeSyntaxError(HTTPException):
@@ -95,7 +99,9 @@ class CodeParser:
         elif isinstance(node, ast.ImportFrom):
             for alias in node.names:
                 if alias.asname:
-                    self.data["imports"].append((node.module, f"{alias.name} as {alias.asname}"))
+                    self.data["imports"].append(
+                        (node.module, f"{alias.name} as {alias.asname}")
+                    )
                 else:
                     self.data["imports"].append((node.module, alias.name))
 
@@ -144,7 +150,9 @@ class CodeParser:
         return_type = None
         if node.returns:
             return_type_str = ast.unparse(node.returns)
-            eval_env = self.construct_eval_env(return_type_str, tuple(self.data["imports"]))
+            eval_env = self.construct_eval_env(
+                return_type_str, tuple(self.data["imports"])
+            )
 
             try:
                 return_type = eval(return_type_str, eval_env)
@@ -185,15 +193,23 @@ class CodeParser:
         num_args = len(node.args.args)
         num_defaults = len(node.args.defaults)
         num_missing_defaults = num_args - num_defaults
-        missing_defaults = [None] * num_missing_defaults
+        missing_defaults = [MissingDefault()] * num_missing_defaults
-        default_values = [ast.unparse(default).strip("'") if default else None for default in node.args.defaults]
+        default_values = [
+            ast.unparse(default).strip("'") if default else None
+            for default in node.args.defaults
+        ]
         # Now check all default values to see if there
         # are any "None" values in the middle
-        default_values = [None if value == "None" else value for value in default_values]
+        default_values = [
+            None if value == "None" else value for value in default_values
+        ]
 
         defaults = missing_defaults + default_values
 
-        args = [self.parse_arg(arg, default) for arg, default in zip(node.args.args, defaults)]
+        args = [
+            self.parse_arg(arg, default)
+            for arg, default in zip(node.args.args, defaults)
+        ]
         return args
 
     def parse_varargs(self, node: ast.FunctionDef) -> List[Dict[str, Any]]:
@@ -211,11 +227,17 @@ class CodeParser:
         """
         Parses the keyword-only arguments of a function or method node.
         """
-        kw_defaults = [None] * (len(node.args.kwonlyargs) - len(node.args.kw_defaults)) + [
+        kw_defaults = [None] * (
-            ast.unparse(default) if default else None for default in node.args.kw_defaults
+            len(node.args.kwonlyargs) - len(node.args.kw_defaults)
+        ) + [
+            ast.unparse(default) if default else None
+            for default in node.args.kw_defaults
         ]
 
-        args = [self.parse_arg(arg, default) for arg, default in zip(node.args.kwonlyargs, kw_defaults)]
+        args = [
+            self.parse_arg(arg, default)
+            for arg, default in zip(node.args.kwonlyargs, kw_defaults)
+        ]
         return args
 
     def parse_kwargs(self, node: ast.FunctionDef) -> List[Dict[str, Any]]:
@@ -319,7 +341,9 @@ class CodeParser:
         Extracts global variables from the code.
         """
         global_var = {
-            "targets": [t.id if hasattr(t, "id") else ast.dump(t) for t in node.targets],
+            "targets": [
+                t.id if hasattr(t, "id") else ast.dump(t) for t in node.targets
+            ],
             "value": ast.unparse(node.value),
         }
         self.data["global_vars"].append(global_var)

src/backend/langflow/interface/custom/schema.py

@@ -27,3 +27,12 @@ class CallableCodeDetails(BaseModel):
     body: list
     return_type: Optional[Any] = None
     has_return: bool = False
+
+
+class MissingDefault:
+    """
+    A class to represent a missing default value.
+    """
+
+    def __repr__(self):
+        return "MISSING"

src/backend/langflow/interface/custom/utils.py

@@ -20,6 +20,7 @@ from langflow.interface.custom.directory_reader.utils import (
     merge_nested_dicts_with_renaming,
 )
 from langflow.interface.custom.eval import eval_custom_component_code
+from langflow.interface.custom.schema import MissingDefault
 from langflow.schema import dotdict
 from langflow.template.field.base import TemplateField
 from langflow.template.frontend_node.custom_components import (
@@ -111,7 +112,7 @@ def extract_type_from_optional(field_type):
     str: The extracted type, or an empty string if no type was found.
     """
     match = re.search(r"\[(.*?)\]$", field_type)
-    return match[1] if match else None
+    return match[1] if match else field_type
 
 
 def get_field_properties(extra_field):
@@ -119,7 +120,13 @@ def get_field_properties(extra_field):
     field_name = extra_field["name"]
     field_type = extra_field.get("type", "str")
     field_value = extra_field.get("default", "")
-    field_required = "optional" not in field_type.lower()
+    # a required field is a field that does not contain
+    # optional in field_type
+    # and a field that does not have a default value
+    field_required = "optional" not in field_type.lower() and isinstance(
+        field_value, MissingDefault
+    )
+    field_value = field_value if not isinstance(field_value, MissingDefault) else None
 
     if not field_required:
         field_type = extract_type_from_optional(field_type)
@@ -469,7 +476,10 @@ def update_field_dict(
 ):
     """Update the field dictionary by calling options() or value() if they are callable"""
     if ("real_time_refresh" in field_dict or "refresh_button" in field_dict) and any(
-        (field_dict["real_time_refresh"], field_dict["refresh_button"])
+        (
+            field_dict.get("real_time_refresh", False),
+            field_dict.get("refresh_button", False),
+        )
     ):
         if call:
             try: