fix: use default values for optional workflow input variables (#28546) (#28527)

Co-authored-by: Claude <noreply@anthropic.com>

api/tests/unit_tests/core/app/apps/test_base_app_generator.py

@@ -50,3 +50,218 @@ def test_validate_input_with_none_for_required_variable():
             )
 
         assert str(exc_info.value) == "test_var is required in input form"
+
+
+def test_validate_inputs_with_default_value():
+    """Test that default values are used when input is None for optional variables"""
+    base_app_generator = BaseAppGenerator()
+
+    # Test with string default value for TEXT_INPUT
+    var_string = VariableEntity(
+        variable="test_var",
+        label="test_var",
+        type=VariableEntityType.TEXT_INPUT,
+        required=False,
+        default="default_string",
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_string,
+        value=None,
+    )
+
+    assert result == "default_string"
+
+    # Test with string default value for PARAGRAPH
+    var_paragraph = VariableEntity(
+        variable="test_paragraph",
+        label="test_paragraph",
+        type=VariableEntityType.PARAGRAPH,
+        required=False,
+        default="default paragraph text",
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_paragraph,
+        value=None,
+    )
+
+    assert result == "default paragraph text"
+
+    # Test with SELECT default value
+    var_select = VariableEntity(
+        variable="test_select",
+        label="test_select",
+        type=VariableEntityType.SELECT,
+        required=False,
+        default="option1",
+        options=["option1", "option2", "option3"],
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_select,
+        value=None,
+    )
+
+    assert result == "option1"
+
+    # Test with number default value (int)
+    var_number_int = VariableEntity(
+        variable="test_number_int",
+        label="test_number_int",
+        type=VariableEntityType.NUMBER,
+        required=False,
+        default=42,
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_number_int,
+        value=None,
+    )
+
+    assert result == 42
+
+    # Test with number default value (float)
+    var_number_float = VariableEntity(
+        variable="test_number_float",
+        label="test_number_float",
+        type=VariableEntityType.NUMBER,
+        required=False,
+        default=3.14,
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_number_float,
+        value=None,
+    )
+
+    assert result == 3.14
+
+    # Test with number default value as string (frontend sends as string)
+    var_number_string = VariableEntity(
+        variable="test_number_string",
+        label="test_number_string",
+        type=VariableEntityType.NUMBER,
+        required=False,
+        default="123",
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_number_string,
+        value=None,
+    )
+
+    assert result == 123
+    assert isinstance(result, int)
+
+    # Test with float number default value as string
+    var_number_float_string = VariableEntity(
+        variable="test_number_float_string",
+        label="test_number_float_string",
+        type=VariableEntityType.NUMBER,
+        required=False,
+        default="45.67",
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_number_float_string,
+        value=None,
+    )
+
+    assert result == 45.67
+    assert isinstance(result, float)
+
+    # Test with CHECKBOX default value (bool)
+    var_checkbox_true = VariableEntity(
+        variable="test_checkbox_true",
+        label="test_checkbox_true",
+        type=VariableEntityType.CHECKBOX,
+        required=False,
+        default=True,
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_checkbox_true,
+        value=None,
+    )
+
+    assert result is True
+
+    var_checkbox_false = VariableEntity(
+        variable="test_checkbox_false",
+        label="test_checkbox_false",
+        type=VariableEntityType.CHECKBOX,
+        required=False,
+        default=False,
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_checkbox_false,
+        value=None,
+    )
+
+    assert result is False
+
+    # Test with None as explicit default value
+    var_none_default = VariableEntity(
+        variable="test_none",
+        label="test_none",
+        type=VariableEntityType.TEXT_INPUT,
+        required=False,
+        default=None,
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_none_default,
+        value=None,
+    )
+
+    assert result is None
+
+    # Test that actual input value takes precedence over default
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_string,
+        value="actual_value",
+    )
+
+    assert result == "actual_value"
+
+    # Test that actual number input takes precedence over default
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_number_int,
+        value=999,
+    )
+
+    assert result == 999
+
+    # Test with FILE default value (dict format from frontend)
+    var_file = VariableEntity(
+        variable="test_file",
+        label="test_file",
+        type=VariableEntityType.FILE,
+        required=False,
+        default={"id": "file123", "name": "default.pdf"},
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_file,
+        value=None,
+    )
+
+    assert result == {"id": "file123", "name": "default.pdf"}
+
+    # Test with FILE_LIST default value (list of dicts)
+    var_file_list = VariableEntity(
+        variable="test_file_list",
+        label="test_file_list",
+        type=VariableEntityType.FILE_LIST,
+        required=False,
+        default=[{"id": "file1", "name": "doc1.pdf"}, {"id": "file2", "name": "doc2.pdf"}],
+    )
+
+    result = base_app_generator._validate_inputs(
+        variable_entity=var_file_list,
+        value=None,
+    )
+
+    assert result == [{"id": "file1", "name": "doc1.pdf"}, {"id": "file2", "name": "doc2.pdf"}]