Clearer error message in Dropdown's and Radio's preprocess function (#…

…9921)

* Clearer error message in Dropdown's and Radio's preprocess function

* add changeset

---------

Co-authored-by: gradio-pr-bot <[email protected]>

.changeset/spicy-cameras-pay.md

@@ -0,0 +1,5 @@
+---
+"gradio": minor
+---
+
+feat:Clearer error message in Dropdown's and Radio's preprocess function

gradio/components/dropdown.py

@@ -196,7 +196,7 @@ def preprocess(
                 for value in payload:
                     if value not in choice_values:
                         raise Error(
-                            f"Value: {value} is not in the list of choices: {choice_values}"
+                            f"Value: {value!r} (type: {type(value)}) is not in the list of choices: {choice_values}"
                         )
             elif payload not in choice_values:
                 raise Error(

gradio/components/radio.py

@@ -117,7 +117,7 @@ def preprocess(self, payload: str | int | float | None) -> str | int | float | N
         choice_values = [value for _, value in self.choices]
         if payload not in choice_values:
             raise Error(
-                f"Value: {payload} is not in the list of choices: {choice_values}"
+                f"Value: {payload!r} (type: {type(payload)}) is not in the list of choices: {choice_values}"
             )
 
         if self.type == "value":

test/components/test_dropdown.py

@@ -14,6 +14,15 @@ def test_component_functions(self):
         assert dropdown_input.preprocess("c full") == "c full"
         assert dropdown_input.postprocess("c full") == ["c full"]
 
+        # Check that the error message clearly indicates the error source in cases where data
+        # representation could be ambiguous e.g. "1" (str) vs 1 (int)
+        dropdown_input = gr.Dropdown([1, 2, 3])
+        # Since pytest.raises takes a regular expression in the `match` argument, we need to escape brackets
+        # that have special meaning in regular expressions
+        expected_error_message = r"Value: '1' \(type: <class 'str'>\) is not in the list of choices: \[1, 2, 3\]"
+        with pytest.raises(gr.Error, match=expected_error_message):
+            dropdown_input.preprocess(["1", "2", "3"])
+
         # When an external Gradio app is loaded with gr.load, the tuples are converted to lists,
         # so we test that case as well
         dropdown = gr.Dropdown(["a", "b", ["c", "c full"]])  # type: ignore

test/components/test_radio.py

@@ -12,6 +12,16 @@ def test_component_functions(self):
         radio_input = gr.Radio(["a", "b", "c"])
         assert radio_input.preprocess("c") == "c"
         assert radio_input.postprocess("a") == "a"
+
+        # Check that the error message clearly indicates the error source in cases where data
+        # representation could be ambiguous e.g. "1" (str) vs 1 (int)
+        radio_input = gr.Radio([1, 2, 3])
+        # Since pytest.raises takes a regular expression in the `match` argument, we need to escape brackets
+        # that have special meaning in regular expressions
+        expected_error_message = r"Value: '1' \(type: <class 'str'>\) is not in the list of choices: \[1, 2, 3\]"
+        with pytest.raises(gr.Error, match=expected_error_message):
+            radio_input.preprocess("1")
+
         radio_input = gr.Radio(
             choices=["a", "b", "c"], value="a", label="Pick Your One Input"
         )