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Application Name and Friendly Name Now Return StringRef

Mar 12, 2026

J. Nick Koston

ESPHome Maintainer

App.get_name() and App.get_friendly_name() now return const StringRef & instead of const std::string &. Most code compiles unchanged because StringRef provides .c_str(), .size(), .empty(), and implicit conversion to std::string. However, binding the result to const std::string & silently creates a heap-allocated temporary — update these references to const auto & to avoid the allocation.

This is a breaking change for external components in ESPHome 2026.3.0 and later.

call_loop(), mark_failed(), and call_dump_config() Are No Longer Virtual

Mar 12, 2026

J. Nick Koston

ESPHome Maintainer

Component::call_loop(), Component::mark_failed(), and Component::call_dump_config() are no longer virtual methods. External components that override any of these methods must remove them entirely and move logic to loop() or dump_config(). This saves 800+ bytes of flash globally from vtable elimination.

This is a breaking change for external components in ESPHome 2026.3.0 and later.

get_loop_priority() Now Conditionally Compiled with USE_LOOP_PRIORITY

Mar 12, 2026

J. Nick Koston

ESPHome Maintainer

The get_loop_priority() virtual method on Component is now only available when USE_LOOP_PRIORITY is defined. This define is only set on RP2040, the only platform where loop priority has an effect. External components that override get_loop_priority() must guard the override with #ifdef USE_LOOP_PRIORITY.

This is a breaking change for external components in ESPHome 2026.3.0 and later.

http_request API Modernization: Vector-Based Headers

Mar 12, 2026

J. Nick Koston

ESPHome Maintainer

The http_request component’s C++ API has been updated to use std::vector instead of std::map, std::list, and std::set for header handling. The get_response_headers() method (returning the full headers map) has been removed — use get_response_header(name) instead. Deprecated overloads using the old container types are provided until 2027.1.0.

This is a breaking change for external components in ESPHome 2026.3.0 and later.

Icon and Device Class Getter Migration

Mar 12, 2026

J. Nick Koston

ESPHome Maintainer

The get_icon_ref(), get_icon(), get_device_class_ref(), and get_device_class() methods are deprecated on all platforms and replaced by new buffer-based APIs get_icon_to() and get_device_class_to(). On ESP8266, the old methods produce a static_assert error because the underlying strings have been moved to PROGMEM and cannot be accessed through normal C string pointers. On other platforms, the old methods continue to work but emit deprecation warnings and will be removed in 2026.9.0.

This is a breaking change for external components in ESPHome 2026.3.0 and later.

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