From 8ee6392b0154378ca336e48b2fd9729ea3343952 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Wed, 18 Mar 2026 10:45:57 -1000
Subject: [PATCH] [ota] Add static_assert for OTAState packing assumption

---
 esphome/components/ota/ota_backend.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/esphome/components/ota/ota_backend.h b/esphome/components/ota/ota_backend.h
index bcefcf4f0d..8a71135477 100644
--- a/esphome/components/ota/ota_backend.h
+++ b/esphome/components/ota/ota_backend.h
@@ -77,6 +77,7 @@ class OTAComponent : public Component {
     // Pack state, error, and progress into a single uint32_t so the lambda
     // captures only [this, packed] (8 bytes) — intended to fit in std::function SBO on supported toolchains.
     // Layout: [state:8][error:8][progress_fixed:16] where progress is 0–10000 (0.01% resolution)
+    static_assert(OTA_ERROR <= 0xFF, "OTAState must fit in 8 bits for packing");
     uint32_t packed = (static_cast<uint32_t>(state) << 24) | (static_cast<uint32_t>(error) << 16) |
                       static_cast<uint16_t>(progress * 100.0f);
     this->defer([this, packed]() {