From b8b219926d182ee90f9621401dc1aea3b42c5ce6 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 7 Mar 2026 08:01:08 -1000
Subject: [PATCH] [core] Skip zero-initialization of StaticVector data array

Remove value-initialization ({}) from StaticVector's underlying
std::array. Only elements [0, count_) are ever accessed, so
initializing the full array is wasted work.

This eliminates a memset on every construction. Most impactful for
stack-allocated StaticVectors in hot paths like
APIPlaintextFrameHelper::write_protobuf_messages, which was
memsetting 276 bytes of iovec storage on every BLE proxy flush.
---
 esphome/core/helpers.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 6ce5de4975..11e0afe526 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -215,7 +215,7 @@ template<typename T, size_t N> class StaticVector {
   using const_reverse_iterator = std::reverse_iterator<const_iterator>;
 
  private:
-  std::array<T, N> data_{};
+  std::array<T, N> data_;  // intentionally not value-initialized to avoid memset
   size_t count_{0};
 
  public: