Replace str_sprintf() with snprintf_P() and PSTR() to keep format
strings in flash instead of RAM. Also removes 'config hash 0x' prefix
to save additional bytes.
Add Application::get_config_version_hash() as a constexpr that returns
fnv1a_hash_extend(config_hash, ESPHOME_VERSION).
Make get_config_hash(), get_build_time(), fnv1a_hash(), and
fnv1a_hash_extend() constexpr inline functions.
Replace open-coded fnv1a_hash_extend(config_hash, ESPHOME_VERSION)
calls with get_config_version_hash() in sensor and wifi components.
Remove now-unnecessary version.h includes from component files.
Add tests covering the logic that detects when source files are removed:
- test_copy_src_tree_detects_removed_source_file: Verifies that removing
a regular source file triggers sources_changed flag
- test_copy_src_tree_ignores_removed_generated_file: Verifies that removing
a generated file (like build_info_data.h) does not trigger sources_changed
Change MQTT sw_version and version text sensor to display config_hash
instead of build_time_str. Format: "(config hash 0xXXXXXXXX)"
Version sensor with hide_timestamp=false also includes build time:
"(config hash 0xXXXXXXXX, built: YYYY-MM-DD HH:MM:SS +ZZZZ)"
Change wifi component to use fnv1a_hash_extend(config_hash, ESPHOME_VERSION)
instead of fnv1_hash(compilation_time) for the preferences hash.
This ensures wifi settings are invalidated on config or version changes,
not just on recompilation.
Change sen5x, sgp30, and sgp4x components to use fnv1a_hash_extend()
starting with config_hash and ESPHOME_VERSION, then extending with the
sensor serial number. This replaces the previous use of fnv1_hash with
compilation_time.
This ensures baseline storage is invalidated on config or version
changes, not just on recompilation.
Keep the API DeviceInfo compilation_time field using the old
get_compilation_time_ref() format for backward compatibility.
The text sensor build_time_str continues to use the new ISO 8601 format.
Increase buffer from 24 to 26 bytes to accommodate the ISO 8601 format
with timezone: "YYYY-MM-DD HH:MM:SS +ZZZZ" (25 chars + null terminator).
The old format "Dec 15 2025, 18:14:59" was 20 chars, but the new format
needs 25 chars. The 24-byte buffer was truncating the timezone to "+00"
instead of "+0000".
David Woodhouse