From 72419eb540353f167595dd9266f002404c64f5b1 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Thu, 17 Jul 2025 07:21:32 -1000
Subject: [PATCH] fix

---
 esphome/components/api/api_pb2.cpp  |  4 +++-
 script/api_protobuf/api_protobuf.py | 13 +++++++++++--
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/esphome/components/api/api_pb2.cpp b/esphome/components/api/api_pb2.cpp
index 64a6fae1a3..437c9ece1d 100644
--- a/esphome/components/api/api_pb2.cpp
+++ b/esphome/components/api/api_pb2.cpp
@@ -1923,7 +1923,9 @@ void BluetoothLERawAdvertisement::calculate_size(uint32_t &total_size) const {
   ProtoSize::add_uint64_field(total_size, 1, this->address);
   ProtoSize::add_sint32_field(total_size, 1, this->rssi);
   ProtoSize::add_uint32_field(total_size, 1, this->address_type);
-  total_size += 1 + ProtoSize::varint(static_cast<uint32_t>(this->data_len)) + this->data_len;
+  if (this->data_len != 0) {
+    total_size += 1 + ProtoSize::varint(static_cast<uint32_t>(this->data_len)) + this->data_len;
+  }
 }
 void BluetoothLERawAdvertisementsResponse::encode(ProtoWriteBuffer buffer) const {
   for (auto &it : this->advertisements) {
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index e245ad4739..f6612be14a 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -663,9 +663,18 @@ class FixedArrayBytesType(TypeInfo):
     def get_size_calculation(self, name: str, force: bool = False) -> str:
         # Use the actual length stored in the _len field
         length_field = f"this->{self.field_name}_len"
-        # Size = field_id_size + varint(length) + actual_data_bytes
         field_id_size = self.calculate_field_id_size()
-        return f"  total_size += {field_id_size} + ProtoSize::varint(static_cast<uint32_t>({length_field})) + {length_field};\n"
+
+        if force:
+            # For repeated fields, always calculate size
+            return f"total_size += {field_id_size} + ProtoSize::varint(static_cast<uint32_t>({length_field})) + {length_field};"
+        else:
+            # For non-repeated fields, skip if length is 0 (matching encode_string behavior)
+            return (
+                f"if ({length_field} != 0) {{\n"
+                f"  total_size += {field_id_size} + ProtoSize::varint(static_cast<uint32_t>({length_field})) + {length_field};\n"
+                f"}}"
+            )
 
     def get_estimated_size(self) -> int:
         # Estimate based on typical BLE advertisement size