fix regarding callable function error (#6294)

* fix regarding callable function error

* add changeset

* fix

* push

---------

Co-authored-by: gradio-pr-bot <gradio-pr-bot@users.noreply.github.com>
Co-authored-by: Abubakar Abid <abubakar@huggingface.co>

.changeset/fruity-spiders-cover.md

@@ -0,0 +1,5 @@
+---
+"gradio": patch
+---
+
+fix: fix regarding callable function error

gradio/helpers.py

@@ -734,7 +734,10 @@ def special_args(
     Returns:
         updated inputs, progress index, event data index.
     """
-    signature = inspect.signature(fn)
+    try:
+        signature = inspect.signature(fn)
+    except ValueError:
+        return inputs or [], None, None
     type_hints = utils.get_type_hints(fn)
     positional_args = []
     for param in signature.parameters.values():

gradio/interface.py

@@ -322,12 +322,17 @@ class Interface(Blocks):
         Interface.instances.add(self)
 
         param_types = utils.get_type_hints(self.fn)
-        param_names = inspect.getfullargspec(self.fn)[0]
-        if len(param_names) > 0 and inspect.ismethod(self.fn):
-            param_names = param_names[1:]
-        for param_name in param_names.copy():
-            if utils.is_special_typed_parameter(param_name, param_types):
-                param_names.remove(param_name)
+        # param_names = inspect.getfullargspec(self.fn)[0]
+        param_names = []
+        try:
+            param_names = inspect.getfullargspec(self.fn)[0]
+            if len(param_names) > 0 and inspect.ismethod(self.fn):
+                param_names = param_names[1:]
+            for param_name in param_names.copy():
+                if utils.is_special_typed_parameter(param_name, param_types):
+                    param_names.remove(param_name)
+        except (TypeError, ValueError):
+            param_names = utils.default_input_labels()
         for component, param_name in zip(self.input_components, param_names):
             assert isinstance(component, Component)
             if component.label is None:

gradio/utils.py

@@ -792,10 +792,13 @@ def is_special_typed_parameter(name, parameter_types):
 def check_function_inputs_match(fn: Callable, inputs: list, inputs_as_dict: bool):
     """
     Checks if the input component set matches the function
-    Returns: None if valid, a string error message if mismatch
+    Returns: None if valid or if the function does not have a signature (e.g. is a built in),
+    or a string error message if mismatch
     """
-
-    signature = inspect.signature(fn)
+    try:
+        signature = inspect.signature(fn)
+    except ValueError:
+        return None
     parameter_types = get_type_hints(fn)
     min_args = 0
     max_args = 0
@@ -948,3 +951,14 @@ class NamedString(str):
     def __init__(self, *args):
         super().__init__()
         self.name = str(self) if args else ""
+
+
+def default_input_labels():
+    """
+    A generator that provides default input labels for components when the user's function
+    does not have named parameters. The labels are of the form "input 0", "input 1", etc.
+    """
+    n = 0
+    while True:
+        yield f"input {n}"
+        n += 1

test/test_interfaces.py

@@ -172,6 +172,11 @@ class TestInterface:
         with Blocks():
             Interface(fn=lambda x: x, inputs=Textbox(), outputs=Image())
 
+    def test_interface_with_built_ins(self):
+        t = Textbox()
+        Interface(fn=str, inputs=t, outputs=Textbox())
+        assert t.label == "input 0"
+
 
 class TestTabbedInterface:
     def test_tabbed_interface_config_matches_manual_tab(self):