From 7782bc11c6a08a35d401e9264e2818a72a0ab02b Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Thu, 27 Aug 2026 15:29:43 -0500
Subject: [PATCH] [core] Remove make_name_with_suffix std::string overloads
 (#18828)

---
 esphome/components/mqtt/mqtt_client.cpp |  6 +++++-
 esphome/config_validation.py            |  2 +-
 esphome/core/helpers.cpp                | 14 --------------
 esphome/core/helpers.h                  | 24 +++---------------------
 4 files changed, 9 insertions(+), 37 deletions(-)

diff --git a/esphome/components/mqtt/mqtt_client.cpp b/esphome/components/mqtt/mqtt_client.cpp
index 1127c36dc6..2ecab47904 100644
--- a/esphome/components/mqtt/mqtt_client.cpp
+++ b/esphome/components/mqtt/mqtt_client.cpp
@@ -41,7 +41,11 @@ MQTTClientComponent::MQTTClientComponent() {
   global_mqtt_client = this;
   char mac_addr[MAC_ADDRESS_BUFFER_SIZE];
   get_mac_address_into_buffer(mac_addr);
-  this->credentials_.client_id = make_name_with_suffix(App.get_name(), '-', mac_addr, MAC_ADDRESS_BUFFER_SIZE - 1);
+  const StringRef &name = App.get_name();
+  char client_id[MAX_NAME_WITH_SUFFIX_SIZE];
+  size_t len = make_name_with_suffix_to(client_id, sizeof(client_id), name.c_str(), name.size(), '-', mac_addr,
+                                        MAC_ADDRESS_BUFFER_SIZE - 1);
+  this->credentials_.client_id.assign(client_id, len);
 }
 
 // Connection
diff --git a/esphome/config_validation.py b/esphome/config_validation.py
index 904cbd1919..aff39201e8 100644
--- a/esphome/config_validation.py
+++ b/esphome/config_validation.py
@@ -1462,7 +1462,7 @@ def hostname(value):
     Maximum length is 63 characters per RFC 1035.
 
     Note: If this limit is changed, update MAX_NAME_WITH_SUFFIX_SIZE in
-    esphome/core/helpers.cpp to accommodate the new maximum length.
+    esphome/core/helpers.h to accommodate the new maximum length.
     """
     value = string(value)
     if re.match(r"^[a-z0-9-]{1,63}$", value, re.IGNORECASE) is not None:
diff --git a/esphome/core/helpers.cpp b/esphome/core/helpers.cpp
index 71e3c87e1e..6bfe5c9e3c 100644
--- a/esphome/core/helpers.cpp
+++ b/esphome/core/helpers.cpp
@@ -268,9 +268,6 @@ char *str_sanitize_to(char *buffer, size_t buffer_size, const char *str) {
 
 // str_sanitize, str_snprintf, str_sprintf moved to alloc_helpers.cpp
 
-// Maximum size for name with suffix: 120 (max friendly name) + 1 (separator) + 6 (MAC suffix) + 1 (null term)
-static constexpr size_t MAX_NAME_WITH_SUFFIX_SIZE = 128;
-
 size_t make_name_with_suffix_to(char *buffer, size_t buffer_size, const char *name, size_t name_len, char sep,
                                 const char *suffix_ptr, size_t suffix_len) {
   size_t total_len = name_len + 1 + suffix_len;
@@ -291,17 +288,6 @@ size_t make_name_with_suffix_to(char *buffer, size_t buffer_size, const char *na
   return total_len;
 }
 
-std::string make_name_with_suffix(const char *name, size_t name_len, char sep, const char *suffix_ptr,
-                                  size_t suffix_len) {
-  char buffer[MAX_NAME_WITH_SUFFIX_SIZE];
-  size_t len = make_name_with_suffix_to(buffer, sizeof(buffer), name, name_len, sep, suffix_ptr, suffix_len);
-  return std::string(buffer, len);
-}
-
-std::string make_name_with_suffix(const std::string &name, char sep, const char *suffix_ptr, size_t suffix_len) {
-  return make_name_with_suffix(name.c_str(), name.size(), sep, suffix_ptr, suffix_len);
-}
-
 // Parsing & formatting
 
 size_t parse_hex(const char *str, size_t length, uint8_t *data, size_t count) {
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 9fdc088ecb..1ccc833048 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -1153,28 +1153,10 @@ inline size_t buf_append_str(char *buf, size_t size, size_t pos, const char *str
 }
 #endif
 
-/// Concatenate a name with a separator and suffix using an efficient stack-based approach.
-/// This avoids multiple heap allocations during string construction.
-/// Maximum name length supported is 120 characters for friendly names.
-/// @param name The base name string
-/// @param sep The separator character (e.g., '-', ' ', or '.')
-/// @param suffix_ptr Pointer to the suffix characters
-/// @param suffix_len Length of the suffix
-/// @return The concatenated string: name + sep + suffix
-std::string make_name_with_suffix(const std::string &name, char sep, const char *suffix_ptr, size_t suffix_len);
+/// Maximum size for name with suffix: 120 (max friendly name) + 1 (separator) + 6 (MAC suffix) + 1 (null term)
+static constexpr size_t MAX_NAME_WITH_SUFFIX_SIZE = 128;
 
-/// Optimized string concatenation: name + separator + suffix (const char* overload)
-/// Uses a fixed stack buffer to avoid heap allocations.
-/// @param name The base name string
-/// @param name_len Length of the name
-/// @param sep Single character separator
-/// @param suffix_ptr Pointer to the suffix characters
-/// @param suffix_len Length of the suffix
-/// @return The concatenated string: name + sep + suffix
-std::string make_name_with_suffix(const char *name, size_t name_len, char sep, const char *suffix_ptr,
-                                  size_t suffix_len);
-
-/// Zero-allocation version: format name + separator + suffix directly into buffer.
+/// Format name + separator + suffix directly into buffer without heap allocation.
 /// @param buffer Output buffer (must have space for result + null terminator)
 /// @param buffer_size Size of the output buffer
 /// @param name The base name string