From 21f270677bd178ff225848befd5b9483370576da Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 9 Feb 2026 04:34:49 -0600
Subject: [PATCH] Future-proof available() check to handle negative return
 values

---
 esphome/components/ld2420/ld2420.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/esphome/components/ld2420/ld2420.cpp b/esphome/components/ld2420/ld2420.cpp
index 01f05b21e5..2fdc73ebb2 100644
--- a/esphome/components/ld2420/ld2420.cpp
+++ b/esphome/components/ld2420/ld2420.cpp
@@ -541,8 +541,10 @@ void LD2420Component::handle_simple_mode_(const uint8_t *inbuf, int len) {
 }
 
 void LD2420Component::read_batch_(std::span<uint8_t, MAX_LINE_LENGTH> buffer) {
+  // All current UART available() implementations return >= 0,
+  // use <= 0 to future-proof against any that may return negative on error.
   int avail = this->available();
-  if (avail == 0) {
+  if (avail <= 0) {
     return;
   }