From 6986e12c4de40ffeaa4be50791d3556bc2575421 Mon Sep 17 00:00:00 2001
From: G Johansson <goran.johansson@shiftit.se>
Date: Sun, 24 Nov 2024 22:21:30 +0000
Subject: [PATCH] Only default if multiple

---
 homeassistant/helpers/config_validation.py | 6 ++++--
 tests/test_data_entry_flow.py              | 2 +-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/homeassistant/helpers/config_validation.py b/homeassistant/helpers/config_validation.py
index 2be633bc084..881d175fa30 100644
--- a/homeassistant/helpers/config_validation.py
+++ b/homeassistant/helpers/config_validation.py
@@ -1136,7 +1136,7 @@ def _custom_serializer(schema: Any, *, allow_section: bool) -> Any:
     if isinstance(schema, data_entry_flow.section):
         if not allow_section:
             raise ValueError("Nesting expandable sections is not supported")
-        return {
+        section_schema = {
             "type": "expandable",
             "schema": voluptuous_serialize.convert(
                 schema.schema,
@@ -1146,8 +1146,10 @@ def _custom_serializer(schema: Any, *, allow_section: bool) -> Any:
             ),
             "expanded": not schema.options["collapsed"],
             "multiple": schema.options["multiple"],
-            "default": schema.options.get("default"),
         }
+        if schema.options["multiple"]:
+            section_schema["default"] = schema.options["default"]
+        return section_schema
 
     if isinstance(schema, multi_select):
         return {"type": "multi_select", "options": schema.options}
diff --git a/tests/test_data_entry_flow.py b/tests/test_data_entry_flow.py
index 33ca3f5d753..4e58d42051c 100644
--- a/tests/test_data_entry_flow.py
+++ b/tests/test_data_entry_flow.py
@@ -1021,7 +1021,7 @@ def test_section_in_serializer() -> None:
         ],
         "type": "expandable",
         "multiple": False,
-        "default": [],
+        "default": None,
     }